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1.
Bone Marrow Transplant ; 56(12): 3042-3048, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34548627

RESUMO

Haploidentical hematopoietic-cell transplantation using post-transplant cyclophosphamide(Haplo-PTCy) is a feasible procedure in children with haematologic malignancies. However, data of a large series of children with acute leukaemia(AL) in this setting is missing. We analysed 144 AL Haplo-PTCy paediatric recipients; median age was 10 years. Patients had acute lymphoblastic(ALL; n = 86) or myeloblastic leukaemia(AML; n = 58) and were transplanted in remission(CR1: n = 40; CR2: n = 57; CR3+: n = 27) or relapse (n = 20). Bone marrow was the graft source in 57%; donors were father (54%), mother (35%), or sibling (11%). Myeloablative conditioning was used in 87%. Median follow-up was 31 months. At day +100, cumulative incidence (CI) of neutrophil recovery and acute GVHD (II-IV) were 94% and 40%, respectively. At 2-years, CI of chronic GVHD and relapse, were 31%, 40%, and estimated 2-year overall survival (OS), leukaemia-free survival (LFS) and graft-versus-host-relapse-free survival (GRFS) were 52%, 44% and 34% respectively. For patients transplanted in remission, positive measurable residual disease (MRD) prior to transplant was associated with decreased LFS (p = 0.05) and GRFS (p = 0.003) and increased risk of relapse (p = 0.02). Mother donor was associated with increased risk of chronic GVHD (p = 0.001), decreased OS (p = 0.03) and GRFS (p = 0.004). Use of PBSC was associated with increased risk of chronic GVHD (p = 0.04). In conclusion, achieving MRD negativity pre-transplant, avoiding use of mother donors and PBSC as graft source may improve outcomes of Haplo-PTCy in children with AL.


Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda , Células-Tronco de Sangue Periférico , Criança , Ciclofosfamida/uso terapêutico , Feminino , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Leucemia Mieloide Aguda/complicações , Mães , Recidiva Local de Neoplasia , Estudos Retrospectivos , Condicionamento Pré-Transplante/métodos , Transplante Haploidêntico/efeitos adversos
2.
Sci Adv ; 6(2): eaaw6284, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31950075

RESUMO

Zika virus (ZIKV) infection during pregnancy is associated with a spectrum of developmental impairments known as congenital Zika syndrome (CZS). The prevalence of this syndrome varies across ZIKV endemic regions, suggesting that its occurrence could depend on cofactors. Here, we evaluate the relevance of protein malnutrition for the emergence of CZS. Epidemiological data from the ZIKV outbreak in the Americas suggest a relationship between undernutrition and cases of microcephaly. To experimentally examine this relationship, we use immunocompetent pregnant mice, which were subjected to protein malnutrition and infected with a Brazilian ZIKV strain. We found that the combination of protein restriction and ZIKV infection leads to severe alterations of placental structure and embryonic body growth, with offspring displaying a reduction in neurogenesis and postnatal brain size. RNA-seq analysis reveals gene expression deregulation required for brain development in infected low-protein progeny. These results suggest that maternal protein malnutrition increases susceptibility to CZS.


Assuntos
Desnutrição/complicações , Infecção por Zika virus/congênito , Infecção por Zika virus/complicações , Animais , Animais Recém-Nascidos , Peso Corporal , Encéfalo/enzimologia , Encéfalo/patologia , Brasil/epidemiologia , Dieta com Restrição de Proteínas , Surtos de Doenças , Embrião de Mamíferos/patologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Desnutrição/virologia , Camundongos Endogâmicos C57BL , Microcefalia/complicações , Microcefalia/virologia , Neurogênese , Tamanho do Órgão , Gravidez , Síndrome , Carga Viral , Infecção por Zika virus/virologia
3.
Braz J Med Biol Res ; 51(5): e6773, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29590259

RESUMO

Bacterial infections occur worldwide and are a major public health problem. Among pathogens, Staphylococcus aureus is the main causative agent of bacterial diseases in the world. This study aimed to evaluate which components of the immune system could act protectively against a S. aureus infection in intradermally immunized mice. C57BL/6 and A/j mice were immunized intradermally with S. aureus inactivated by heat and then challenged with viable strains in an air pouch model. At 6, 12, and 24 h after the challenge, euthanasia was performed, and the cellular profile of the inflammatory infiltrate, cytokines, and the bacterial load were evaluated in the air pouch lavages. Immunized mice demonstrated that the intradermal immunization with S. aureus promoted protection in C57BL/6 mice by reducing the bacterial, which was correlated with increased serum concentration of IgG antibodies (IgG1 and IgG2a) against S. aureus. The increase in IgG2a antibody levels was correlated with a decrease of bacterial load in intradermally immunized C57BL/6 mice, along with production of IL-17A at the inflammation site, as well as IgG1consumption. Similar results were not found in the A/j lineage. In conclusion, a vaccine against S. aureus should focus more on the individual characteristics of the host because it is a determinant factor for the success of the immunization.


Assuntos
Anticorpos Antibacterianos/imunologia , Staphylococcus aureus Resistente à Meticilina/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinas Antiestafilocócicas/imunologia , Animais , Carga Bacteriana , Citocinas/imunologia , Modelos Animais de Doenças , Imunoglobulina G/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções Estafilocócicas/imunologia , Vacinas Antiestafilocócicas/administração & dosagem , Fatores de Tempo
4.
Clin Oral Investig ; 19(9): 2345-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25825124

RESUMO

OBJECTIVES: This study was planned to evaluate the impact of oral health on the quality of life (QoL) of patients undergoing hematopoietic stem cell transplantation (HSCT). MATERIAL AND METHODS: We assessed 200 patients divided into two paired groups: 100 patients prior to HSCT (SG) and 100 healthy volunteers (CG). We applied the Oral Health Impact Profile instrument, which is based on the biopsychosocial problem gradation of World Health Organization (WHO) and relates oral health problems with QoL according to seven dimensions. RESULTS: Fourteen patients in SG were referred for extraction of one to eight teeth, mostly due to deep caries with risk of pulpal infection and possible spread of infection via blood (r = 0.59, p = 0.000). The presence of severely compromised teeth by extensive decay correlated with Oral Health Impact Profile (OHIP-14). The Mann-Whitney test showed a significant difference between SG and CG in the following dimensions: functional limitation (p < 0.001), physical pain (p = 0.025), physical disability (p = 0.016), and social disability (p = 0.01). CONCLUSIONS: The impact of oral health on QoL of onco-hematologic patients is weak but is greater as compared to healthy ones. Nevertheless, a significant impact is seen in patients with severely compromised teeth. CLINICAL RELEVANCE: The negligence of oral care, proper hygiene, and the search for dental care may increase the risk for local and systemic infections.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Saúde Bucal , Qualidade de Vida , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Perfil de Impacto da Doença , Inquéritos e Questionários , Doenças Dentárias/epidemiologia
5.
Bone Marrow Transplant ; 50(5): 685-9, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25730184

RESUMO

Patients with refractory severe aplastic anemia (SAA) who lack a matched sibling or unrelated donor need new therapeutic approaches. Hematopoietic SCT (HSCT) using mismatched or haploidentical related donors has been used in the past, but was associated with a significant risk of GVHD and mortality. Recently, the use of post-transplant cyclophosphamide (Cy) has been shown to be an effective strategy to prevent GVHD in recipients of haploidentical HSCT, but the majority of reports have focused on patients with hematology malignancies. We describe the outcome of 16 patients who underwent haploidentical transplantation using a reduced-intensity conditioning regimen with post-transplant Cy. Stem cell sources were BM (N=13) or PBSCs (N=3). The rate of neutrophil engraftment was 94% and of platelet engraftment was 75%. Two patients had secondary graft failure and were successfully salvaged with another transplant. Three patients developed acute GVHD being grades 2-4 in two. Five patients have died and the 1-year OS was 67.1% (95% confidence interval: 36.5-86.4%). In our small series, the use of a reduced-intensity conditioning with post-transplant Cy in haploidentical BMT was associated with high rates of engraftment and low risk of GVHD in patients with relapsed/refractory SAA.


Assuntos
Anemia Aplástica/terapia , Transplante de Medula Óssea , Ciclofosfamida/administração & dosagem , Doença Enxerto-Hospedeiro/prevenção & controle , Imunossupressores/administração & dosagem , Condicionamento Pré-Transplante , Doença Aguda , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
6.
Food Chem Toxicol ; 51: 46-52, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23000443

RESUMO

Few chronic food protein models have described the relationship between allergenicity and the molecular structure of food protein after physical processing. The effect of γ-radiation on the structure of food protein was measured by fluorescence, circular dichroism and microcalorimetry. BALB/c mice were intraperitoneally sensitized and then given non-irradiated and irradiated Con-A by daily gavage for 28days. The tendency to form insoluble amorphous aggregates and partially unfolded species was observed after irradiation. The administration of non-irradiated and irradiated samples at low-dose significantly increased weight loss as well as plasma levels of eotaxin in animals repeatedly exposed to Con-A. Significant lymphocytic infiltrate filling completely the stroma of microvilli and tubular glands was observed in the small intestinal of the group given Con-A irradiated at a low dose. This phenotype was not observed in animals treated with Con-A irradiated at a high dose.


Assuntos
Concanavalina A/química , Concanavalina A/imunologia , Concanavalina A/efeitos da radiação , Hipersensibilidade Alimentar/etiologia , Administração Oral , Animais , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Concanavalina A/administração & dosagem , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Feminino , Hipersensibilidade Alimentar/patologia , Raios gama , Intestino Delgado/imunologia , Intestino Delgado/patologia , Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Microvilosidades/imunologia , Microvilosidades/patologia , Conformação Proteica , Redução de Peso
7.
Interv Neuroradiol ; 15(1): 93-8, 2009 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-20465936

RESUMO

SUMMARY: Endovascular treatment of complex intracranial lesions often requires use of two different microcatheters or micro-guidewires. A basilar artery aneurysm was treated with microstent-assisted coiling. During the procedure a microwire severed and the distal platinum portion of the wire was left after unsuccessful attempts to retrieve it. The patient remains asymptomatic. The proximal part of the microwire was analyzed and additional experiments indicate that it may have detached by electrolytic corrosion.

8.
J Pharm Biomed Anal ; 46(1): 18-29, 2008 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-18037599

RESUMO

A set of Good Clinical Laboratory Practice (GCLP) standards that embraces both the research and clinical aspects of GLP were developed utilizing a variety of collected regulatory and guidance material. We describe eleven core elements that constitute the GCLP standards with the objective of filling a gap for laboratory guidance, based on IND sponsor requirements, for conducting laboratory testing using specimens from human clinical trials. These GCLP standards provide guidance on implementing GLP requirements that are critical for laboratory operations, such as performance of protocol-mandated safety assays, peripheral blood mononuclear cell processing and immunological or endpoint assays from biological interventions on IND-registered clinical trials. The expectation is that compliance with the GCLP standards, monitored annually by external audits, will allow research and development laboratories to maintain data integrity and to provide immunogenicity, safety, and product efficacy data that is repeatable, reliable, auditable and that can be easily reconstructed in a research setting.


Assuntos
Pesquisa Biomédica/normas , Guias como Assunto/normas , Laboratórios/normas , Sistemas de Informação em Laboratório Clínico/normas , Humanos , Cooperação Internacional , Controle de Qualidade
9.
Bone Marrow Transplant ; 40(9): 859-63, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17724445

RESUMO

We report here the first six cases of leprosy associated with HLA-identical allogeneic SCT in different phases and with different findings and outcomes. Skin and peripheral nerves may be sites of leprosy associated with SCT, stressing the importance of differential diagnosis between leprosy and GVHD or drug reactions. Clinical manifestations of leprosy before or after transplantation did not influence the outcome of SCT in our cases.


Assuntos
Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Hanseníase/etiologia , Adulto , Diagnóstico Diferencial , Feminino , Humanos , Hanseníase/diagnóstico , Hanseníase/patologia , Masculino , Doenças do Sistema Nervoso Periférico/diagnóstico , Doenças do Sistema Nervoso Periférico/etiologia , Dermatopatias/diagnóstico , Dermatopatias/etiologia , Transplante Homólogo , Resultado do Tratamento
10.
Interv Neuroradiol ; 11(1): 79-82, 2005 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-20584440

RESUMO

SUMMARY: HHT (Hereditary Haemorrhagic Telangiectasia or Rendu Osler Weber disease) is a known autosomal dominant dysplasia. The first clinical presentation of HHT in a child may be a cerebral or spinal AVM. We present the case of a young boy with HHT who had a previous spinal cord AVF treated by surgical obliteration and then presented with a spinal dural AVF nine months later. This patient had surgical obliteration of a spinal cord perimedullary AVF and subsequently developed a new spinal dural AVF at a different level. The diagnosis was made by spinal MR imaging and spinal angiography.

11.
Neuroradiology ; 46(12): 1016-21, 2004 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-15570419

RESUMO

We report the cases of three patients diagnosed with dural arteriovenous fistula (DAVF) and cortical venous reflux (CVR). All were treated by transarterial endovascular embolization. Residual shunting and cortical venous drainage continued to be present at the end of the treatment procedure, despite the fact that during endovascular embolization glue penetration into the proximal venous component of the fistula had been achieved. Subsequently, follow-up angiography showed total obliteration of the fistulas and absent associated CVR. The fistulas were no longer opacified, and no additional treatment was performed. We demonstrate that residual aggressive DAVF may progress to total thrombosis if strategic deposition of the glue into the venous side has been achieved. Early follow-up angiogram is recommended prior to a planned complementary surgical approach.


Assuntos
Malformações Vasculares do Sistema Nervoso Central/terapia , Embolização Terapêutica , Trombose Intracraniana , Insuficiência Venosa/terapia , Idoso , Malformações Vasculares do Sistema Nervoso Central/complicações , Malformações Vasculares do Sistema Nervoso Central/diagnóstico por imagem , Feminino , Humanos , Trombose Intracraniana/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Radiografia , Resultado do Tratamento , Insuficiência Venosa/complicações , Insuficiência Venosa/diagnóstico por imagem
12.
Neuroradiology ; 46(2): 156-60, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14655033

RESUMO

There are multiple transvenous approaches for treatment of cavernous dural arteriovenous fistulae (DAVF). The choice of a specific route depends on the compartment of the cavernous sinus involved in the fistula and its venous drainage. We used two different facial vein approaches to treat patients with cavernous DAVF draining directly into the anterior compartment of the cavernous sinus and thence to the superior ophthalmic vein. Other transvenous routes to the sinus were not apparent. Embolization was targeted to the involved compartment with preservation of those not embolized. No major post-procedure ophthalmic venous engorgement occurred. We believe that ideal treatment of cavernous DAVF is targeted transvenous coil deposition, which necessitates detailed knowledge of the anatomy of the facial veins and cavernous sinus compartments.


Assuntos
Seio Cavernoso , Malformações Vasculares do Sistema Nervoso Central/terapia , Angiografia Cerebral , Embolização Terapêutica/métodos , Fístula/terapia , Flebografia , Adulto , Artérias Carótidas/diagnóstico por imagem , Seio Cavernoso/diagnóstico por imagem , Seio Cavernoso/patologia , Malformações Vasculares do Sistema Nervoso Central/diagnóstico por imagem , Exoftalmia/diagnóstico por imagem , Exoftalmia/etiologia , Face/irrigação sanguínea , Feminino , Fístula/diagnóstico por imagem , Seguimentos , Humanos , Veias Jugulares/diagnóstico por imagem , Pessoa de Meia-Idade , Hipertensão Ocular/diagnóstico por imagem , Hipertensão Ocular/etiologia , Órbita/irrigação sanguínea
13.
Interv Neuroradiol ; 10(4): 309-14, 2004 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-20587214

RESUMO

SUMMARY: In this case presentation we describe a patient with an anomalous origin of the right vertebral artery arising from the right common carotid artery in combination with an aberrant right subclavian artery and a left vertebral artery originating from the arch between the left common carotid artery and left subclavian artery. Hence there were five vessels originating from the aortic arch. The possible embryological mechanism as well as a postulation on the importance of the level of entrance of the vertebral artery in the cervical transverse foramen is discussed.

14.
Chemosphere ; 52(9): 1571-9, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12867190

RESUMO

Wetland microcosms were used to evaluate the ability of constructed wetlands to remove extremely high concentrations of selenocyanate (SeCN-), arsenic (As), and boron (B) from wastewater generated by a coal gasification plant in Indiana. The wetland microcosms significantly reduced the concentrations of selenium (Se), As, B, and cyanide (CN) in the wastewater by 64%, 47%, 31%, and 30%, respectively. In terms of the mass of each contaminant, 79%, 67%, 57%, and 54% of the Se, As, B, and CN, respectively, loaded into the microcosms were removed from the wastewater. The primary sink for the retention of contaminants within the microcosms was the sediment, which accounted for 63%, 51%, and 36% of the Se, As, and B, respectively. Accumulation in plant tissues accounted for only 2-4%, while 3% of the Se was removed by biological volatilization to the atmosphere. Of the 14 plant species tested, cattail, Thalia, and rabbitfoot grass were highly tolerant of the contaminants and exhibited no growth retardation. Environmental toxicity testing with fathead minnow (Pimephales promelas) larvae confirmed that the water treated by the wetland microcosms was less toxic than untreated water. The data from the wetland microcosms support the view that constructed wetlands could be used to successfully reduce the toxicity of aqueous effluent contaminated with extremely high concentrations of SeCN-, As, and B, and that a pilot-scale wetland should therefore be constructed to test this in the field. Cattail, Thalia, and rabbitfoot grass would be suitable plant species to establish in such wetlands.


Assuntos
Arsênio/isolamento & purificação , Boro/isolamento & purificação , Cianatos/isolamento & purificação , Ecossistema , Compostos de Selênio/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Microbiologia da Água , Purificação da Água/métodos , Animais , Arsênio/análise , Arsênio/farmacocinética , Intoxicação por Arsênico/prevenção & controle , Biomassa , Boro/análise , Boro/farmacocinética , Boro/intoxicação , Cianatos/análise , Cianatos/farmacocinética , Cianatos/intoxicação , Cyprinidae , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Raízes de Plantas/química , Brotos de Planta/química , Plantas/metabolismo , Compostos de Selênio/análise , Compostos de Selênio/farmacocinética , Compostos de Selênio/intoxicação , Distribuição Tecidual , Volatilização , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/farmacocinética
15.
Plant Cell Environ ; 26(6): 897-905, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12803617

RESUMO

An axenically cultured isolate of single-celled freshwater microalgae (Chlorella sp.) metabolized toxic selenate to volatile dimethylselenide at exceptionally high rates when transferred from mineral-nutrient solution to water for 24 h. The Se-volatilization rates were orders of magnitude higher than those similarly measured for wetland macroalgae and higher plants. Ninety percent of 20 micro m selenate supplied to the microalgae incubated without nutrients was removed through accumulation and volatilization. Additions of 1 mm sulphate but not nitrate, inhibited Se accumulation and volatilization so that only 1.8% of the supplied selenate was removed. The microalgae cultured in nutrient solution without sulphate showed increased 35S-sulphate-transporter activity. Selenium K-edge X-ray absorption spectroscopy of selenate-treated microalgae cultured with or without mineral nutrients, showed that 87% of the selenate accumulated during 24 h was reductively metabolized to intermediate organic compounds such as selenomethionine and selenocystine. This is in complete contrast to higher plants that show very limited reduction of selenate. It appears that high rates of Se accumulation and volatilization by the sulphate-deprived microalgae resulted from reduced competition with chemically analogous sulphate ions for selenate uptake via up-regulated sulphate/selenate transporters and rapid reductive metabolism of selenate. Hyper-volatilization of selenate by microalgal cells may provide a novel detoxification response.

17.
Appl Environ Microbiol ; 67(9): 3785-94, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11525968

RESUMO

Solar evaporation ponds are commonly used to reduce the volume of seleniferous agricultural drainage water in the San Joaquin Valley, Calif. These hypersaline ponds pose an environmental health hazard because they are heavily contaminated with selenium (Se), mainly in the form of selenate. Se in the ponds may be removed by microbial Se volatilization, a bioremediation process whereby toxic, bioavailable selenate is converted to relatively nontoxic dimethylselenide gas. In order to identify microbes that may be used for Se bioremediation, a 16S ribosomal DNA phylogenetic analysis of an aerobic hypersaline pond in the San Joaquin Valley showed that a previously unaffiliated group of uncultured bacteria (belonging to the order Cytophagales) was dominant, followed by a group of cultured gamma-Proteobacteria which was closely related to Halomonas species. Se K-edge X-ray absorption spectroscopy of selenate-treated bacterial isolates showed that they accumulated a mixture of predominantly selenate and a selenomethionine-like species, consistent with the idea that selenate was assimilated via the S assimilation pathway. One of these bacterial isolates (Halomonas-like strain MPD-51) was the best candidate for the bioremediation of hypersaline evaporation ponds contaminated with high Se concentrations because it tolerated 2 M selenate and 32.5% NaCl, grew rapidly in media containing selenate, and accumulated and volatilized Se at high rates (1.65 microg of Se g of protein(-1) x h(-1)), compared to other cultured bacterial isolates.


Assuntos
Bacteroidetes/classificação , Gammaproteobacteria/classificação , Selênio/metabolismo , Cloreto de Sódio , Microbiologia da Água , Poluentes Químicos da Água/metabolismo , Agricultura , Bacteroidetes/genética , Bacteroidetes/isolamento & purificação , Bacteroidetes/fisiologia , Biodegradação Ambiental , DNA Ribossômico/análise , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Gammaproteobacteria/fisiologia , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S
18.
Environ Sci Technol ; 35(15): 3144-50, 2001 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11505990

RESUMO

Thlaspi caerulescens has a remarkable ability to hyperaccumulate Zn from soils containing mostly nonlabile Zn. The present study shows that rhizosphere microbes play an important role in increasing the availability of water-soluble Zn in soil, thus enhancing Zn accumulation by T. caerulescens. The addition of bacteria to surface-sterilized seeds of T. caerulescens sown in autoclaved soil increased the Zn concentration in shoots 2-fold as compared to axenic controls; the total accumulation of Zn was enhanced 4-fold. When the same experiment was conducted with Thlaspi arvense, a nonaccumulator, bacteria had no effect on shoot Zn accumulation although they increased water-soluble Zn concentrations available to both Thlaspi species by 22-67% as compared to the axenic controls. Further evidence that bacteria increase the availability of water-soluble Zn in soil was obtained when liquid media that had supported bacterial growth mobilized 1.3-1.8-fold more Zn from soil as compared to axenic media. Other experiments with agar media showed that bacteria did not facilitate an increase in the rate of soluble Zn transport into the root nor did they enlarge the surface area of the roots of either Thlaspi species. Thus, the bacterially mediated increase in the dissolution of Zn from the nonlabile phase in soil may enhance Zn accumulation in T. caerulescens shoots.


Assuntos
Brassicaceae/fisiologia , Raízes de Plantas/microbiologia , Poluentes do Solo/farmacocinética , Zinco/farmacocinética , Disponibilidade Biológica , Enterobacter/fisiologia , Raízes de Plantas/fisiologia , Pseudomonas/fisiologia , Solubilidade , Água
19.
JAMA ; 284(2): 215-22, 2000 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-10889596

RESUMO

Great strides have been made in developing potent antiretroviral regimens that block human immunodeficiency virus (HIV) transcription and assembly. Despite these therapeutic advances, problems of drug resistance, latent viral reservoirs, and drug-induced toxic effects that compromise effective viral control point to the need for new classes of anti-HIV drugs with different modes of action. One promising approach involves blocking HIV entry into human cells, a complex process that involves multiple protein interactions. The process of HIV entry begins with binding of the viral envelope glycoprotein to both the CD4 receptor and one of several chemokine receptors and ends with fusion of viral and cell membranes. Conceptually, there are 3 steps in the HIV entry process that could serve as therapeutic targets: binding of the viral envelope glycoprotein with the CD4 receptor, binding of the envelope-CD4 complex to chemokine receptors, and fusion of the viral and cell membranes. Preclinical and clinical assessment of these entry inhibitors is ongoing and will determine if they possess properties required for drug licensure. Moreover, the worldwide epidemic is largely occurring in developing countries that cannot afford these drugs: a prophylactic vaccine is necessary and urgent. New knowledge of the HIV-envelope glycoprotein has also provided insight into possibilities for the design of novel HIV vaccines. JAMA. 2000;284:215-222


Assuntos
Vacinas contra a AIDS/farmacologia , Fármacos Anti-HIV/farmacologia , Infecções por HIV/prevenção & controle , HIV/efeitos dos fármacos , Antígenos CD4/metabolismo , Desenho de Fármacos , Previsões , HIV/patogenicidade , Humanos , Fusão de Membrana/efeitos dos fármacos , Farmacologia/tendências , Ligação Proteica/efeitos dos fármacos , Receptores de Quimiocinas/metabolismo , Proteínas do Envelope Viral/metabolismo
20.
Plant Physiol ; 122(4): 1281-8, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10759525

RESUMO

Earlier work from our laboratory on Indian mustard (Brassica juncea L.) identified the following rate-limiting steps for the assimilation and volatilization of selenate to dimethyl selenide (DMSe): (a) uptake of selenate, (b) activation of selenate by ATP sulfurylase, and (b) conversion of selenomethionine (SeMet) to DMSe. The present study showed that shoots of selenate-treated plants accumulated very low concentrations of dimethylselenoniopropionate (DMSeP). Selenonium compounds such as DMSeP are the most likely precursors of DMSe. DMSeP-supplied plants volatilized Se at a rate 113 times higher than that measured from plants supplied with selenate, 38 times higher than from selenite, and six times higher than from SeMet. The conversion of SeMet to selenonium compounds such as DMSeP is likely to be rate-limiting for DMSe production, but not the formation of DMSe from DMSeP because DMSeP was the rate of Se volatilization from faster than from SeMet and SeMet (but no DMSeP) accumulated in selenite- or SeMet-supplied wild-type plants and in selenate-supplied ATP-sulfurylase transgenic plants. DMSeP-supplied plants absorbed the most Se from the external medium compared with plants supplied with SeMet, selenate, or selenite; they also accumulated more Se in shoots than in roots as an unknown organic compound resembling a mixture of DMSeP and selenocysteine.


Assuntos
Brassica/metabolismo , Propionatos/química , Selênio/metabolismo , Selênio/química , Volatilização
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