Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 153
Filtrar
1.
Exp Brain Res ; 241(3): 727-741, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36708380

RESUMO

BACKGROUND: Long-term sequelae of COVID-19 can result in reduced functionality of the central nervous system and substandard quality of life. Gaining insight into the recovery trajectory of admitted COVID-19 patients on their cognitive performance and global structural brain connectivity may allow a better understanding of the diseases' relevance. OBJECTIVES: To assess whole-brain structural connectivity in former non-intensive-care unit (ICU)- and ICU-admitted COVID-19 survivors over 2 months following hospital discharge and correlate structural connectivity measures to cognitive performance. METHODS: Participants underwent Magnetic Resonance Imaging brain scans and a cognitive test battery after hospital discharge to evaluate structural connectivity and cognitive performance. Multilevel models were constructed for each graph measure and cognitive test, assessing the groups' influence, time since discharge, and interactions. Linear regression models estimated whether the graph measurements affected cognitive measures and whether they differed between ICU and non-ICU patients. RESULTS: Six former ICU and six non-ICU patients completed the study. Across the various graph measures, the characteristic path length decreased over time (ß = 0.97, p = 0.006). We detected no group-level effects (ß = 1.07, p = 0.442) nor interaction effects (ß = 1.02, p = 0.220). Cognitive performance improved for both non-ICU and ICU COVID-19 survivors on four out of seven cognitive tests 2 months later (p < 0.05). CONCLUSION: Adverse effects of COVID-19 on brain functioning and structure abate over time. These results should be supported by future research including larger sample sizes, matched control groups of healthy non-infected individuals, and more extended follow-up periods.


Assuntos
COVID-19 , Humanos , COVID-19/patologia , Qualidade de Vida , Encéfalo/patologia , Cognição , Sobreviventes
2.
Climacteric ; 26(3): 182-192, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37051868

RESUMO

The sex steroid hormone estrogen plays a number of regulatory roles in female development. During menopause, estrogen synthesis in the ovaries decreases, which results in adverse physiological remodeling and increased risk of disease. Reduced bone density, changes in the community composition profiles of the gut and vaginal microbiome, mood swings and changes in the vaginal environment are to be expected during this time. To alleviate these changes, postmenopausal women can be prescribed hormone replacement therapy (HRT) through the use of exogenous estradiol, often in conjunction with progestin treatment, which re-induces estrogenic action throughout the body. The microbiome and estrogen have a bidirectional, regulatory relationship in the gut, while in the vaginal environment estrogen works indirectly on the microbiome through restoring the vaginal tissue environment that leads to microbial homeostasis. This review discusses what is known about how the gut and vaginal microbiomes of postmenopausal women are responding to HRT, and the potential future of microbe-based therapeutics for symptoms of menopause.


Assuntos
Microbiota , Pós-Menopausa , Feminino , Humanos , Pós-Menopausa/fisiologia , Terapia de Reposição Hormonal , Menopausa , Estrogênios/farmacologia , Terapia de Reposição de Estrogênios
3.
Wound Repair Regen ; 29(1): 8-19, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32789902

RESUMO

Pathological scars can result in functional impairment, disfigurement, a psychological burden, itch, and even chronic pain. We conducted a systematic review to investigate the influence of incisional Negative Pressure Wound Therapy (iNPWT) on scarring. PubMed, EMBASE and CINAHL were searched for preclinical and clinical comparative studies that investigated the influence of iNPWT on scarring-related outcomes. Individual studies were assessed using the OHAT Risk of Bias Rating Tool for Human and Animal studies. The body of evidence was rated using OHAT methodology. Six preclinical studies and nine clinical studies (377 patients) were identified. Preclinical studies suggested that iNPWT reduced lateral tension on incisions, increased wound strength, and reduced scar width upon histological assessment. Two clinical studies reported improved patient-reported scar satisfaction as measured with the PSAS (1 year after surgery), POSAS, and a VAS (both 42, 90, and 180 days after surgery). Five clinical studies reported improved observer-reported scar satisfaction as measured with the VSS, SBSES, OSAS, MSS, VAS, and POSAS (7, 15, 30, 42, 90, 180, and 365 days after surgery). Three clinical studies did not detect significant differences at any point in time (POSAS, VAS, and NRS). Because of imprecision concerns, a moderate level of evidence was identified using OHAT methodology. Preclinical as well as clinical evidence indicates a beneficial influence of iNPWT on scarring. Moderate level evidence indicates that iNPWT decreases scar width and improves patient and observer-reported scar satisfaction.


Assuntos
Cicatriz/prevenção & controle , Tratamento de Ferimentos com Pressão Negativa/métodos , Infecção da Ferida Cirúrgica/terapia , Cicatrização , Animais , Cicatriz/etiologia , Humanos , Infecção da Ferida Cirúrgica/complicações
4.
Rev Med Chil ; 148(12): 1855-1859, 2020 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-33844755

RESUMO

This work addresses the controverted reproductive health policies in the last fifty years in the United States and in the last thirty years in Chile, since the return of democracy. They range from the inclusion of sex education programs in school curricula to the voluntary interruption of pregnancy and the recent emergence of institutional conscientious objection. The author provides a comparative analysis of the latter in both countries, considering the current political context in the United States and the constituent process development in Chile.


Assuntos
Aborto Induzido , Saúde Reprodutiva , Chile , Feminino , Política de Saúde , Humanos , Gravidez , Estados Unidos
5.
Vox Sang ; 113(7): 701-706, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30144091

RESUMO

While specific practices and transported blood products vary around the world, most of the respondents in this International Forum transported at least one blood product for the transfusion to bleeding patients en route to the hospital. The most commonly carried product was RBCs, while the use of whole blood will likely increase given the recent reports of its successful use in the civilian setting, and because of the change in the AABB's Standards regulating its use. It will be interesting to see if plasma use in the prehospital setting becomes more widely used given today's enhanced appreciated of the coagulopathy of trauma and plasma's beneficial effect in reversing it, and if blood products are transported to the scene of injury by more vehicles, that is, not just predominantly in helicopters. It was not surprising that TXA is being widely administered as close to the time of injury as possible given its potential benefit in these patients. This International Forum highlights the importance of focusing attention on prehospital transfusion management with a need to further high­quality research in this area to guide optimal resuscitation strategies.


Assuntos
Transfusão de Sangue/métodos , Congressos como Assunto , Serviços Médicos de Emergência/métodos , Hemorragia/terapia , Substitutos Sanguíneos/uso terapêutico , Humanos
6.
J Appl Microbiol ; 2018 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-30146755

RESUMO

AIMS: The effect of insect exclusion via netting on bacterial microbiota associated with field-grown tomato fruit and flowers was evaluated. METHODS AND RESULTS: Amplicon-based bacterial community profiling from insect-exposed plants and plants wrapped in nylon mosquito netting was conducted on total DNA extracted from tomato flower and mature unripe fruit washes. The V1-V3 region of the 16S rRNA gene was sequenced using Illumina MiSeq and analysed using qiime ver. 1.8. The carposphere supported significantly more phylogenetic diversity (PD) compared to the anthosphere, as measured by operational taxonomic unit richness (P = 0·001) and Faith's PD (P = 0·004). Flowers and fruit hosted distinct bacterial community structures (R2 = 0·27, P = 0·001), with specific taxonomic differences in taxa that included the Xanthomonadaceae (higher in flowers), and the Pseudomonadaceae, Methylobacteriaceae and Rhizobiales (higher in fruit) (FDR-P < 0·05). Bacterial community profiles of netted plants were overall statistically similar to non-netted plants for both flowers and fruit (P > 0·10). However, less variation between samples was observed among flowers (~50% less, P = 0·004) and green fruit (~10% less, P = 0·038) collected from netted than non-netted plants. CONCLUSION: Insects may introduce or augment variability in bacterial diversity associated with tomato flowers and potentially green fruit surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: This work contributes to knowledge on microbiome dynamics of the tomato holobiont. Deciphering drivers of bacterial diversity and community structure of fruit crops could reveal processes important to agricultural management, such as competitive exclusion of pathogens and priming of plant defense mechanisms.

7.
Transfus Med ; 28(4): 271-276, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29193375

RESUMO

OBJECTIVES: The aim of this study was to assess current practices around obtaining consent for blood transfusion and provision of patient information in hospitals across the UK and identify areas for improvement. BACKGROUND: Recommendations from the Advisory Committee on the Safety of Blood, Tissues and Organs (SaBTO) (2011) state that valid consent should be obtained for blood transfusion and documented in clinical records. A standardised source of information should be available to patients. Practices in relation to this have historically been inconsistent. METHODS: The consent process was studied in hospitals across the UK over a 3-month period in 2014 by means of an audit of case notes and simultaneous surveys of patients and staff. RESULTS: In total, 2784 transfusion episodes were reviewed across 164 hospital sites. 85% of sites had a policy on consent for transfusion. Consent was documented in 43% of case notes. 68% of patients recalled being given information on benefits of transfusion, 38% on risks and 8% on alternatives and 28% reported receiving an information leaflet. In total, 85% of staff stated they had explained the reason for transfusion, but only 65% had documented this. 41% of staff had received training specifically on transfusion consent in the last 2 years. CONCLUSIONS: There is a need to improve clinical practice in obtaining valid consent for transfusion in line with existing national guidelines and local Trust policies, with emphasis on documentation within clinical records. Provision of patient information is an area particularly highlighted for action, and transfusion training for clinicians should be strengthened.


Assuntos
Transfusão de Sangue , Consentimento Livre e Esclarecido , Auditoria Médica , Humanos , Reino Unido
8.
Transfus Med ; 28(1): 56-59, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28295747

RESUMO

BACKGROUND: Haemorrhage is the leading cause of mortality during trauma. In 2012, London's Air Ambulance introduced Blood on Board (BOB), transfusing group O red cells (RBC) to trauma patients at the scene. OBJECTIVES: This study assessed the impact of BOB on the number of mixed field samples received by the laboratory, the number of group O RBC transfused to non-group O patients and the ratio of RBC to fresh frozen plasma (FFP) transfused in the initial 24 h. METHODS: Three major trauma centres collected data on patients for whom the major haemorrhage protocol was activated between August 2008 and February 2012 pre-BOB and March 2012 and December 2013 post-BOB. RESULTS: A total of 233 trauma patients were identified pre-BOB and 119 post-BOB. There was no significant difference in the percentage of group O units transfused to non-group O patients (75 vs 82%, P = 0·21) or the RBC : FFP ratio (pre-BOB mean 1·6 [interquartile range (IQR) 1·0-2·0]; post-BOB mean 1·7 [IQR 1·1-2·2], P = 0·24). There was no significant difference in the percentage of mixed field samples received (23% vs 27%, P = 0·3). CONCLUSION: The introduction of BOB did not change the proportion of group O RBC transfused or the RBC : FFP ratio; however, the proportion of acceptable samples decreased. This is largely due to an increase in blood samples not received from the post-BOB cohort, which we believe is probably due to patients who died at the scene. We have introduced robust systems to indicate reasons for not obtaining samples.


Assuntos
Sistema ABO de Grupos Sanguíneos , Ambulâncias , Segurança do Sangue , Transfusão de Eritrócitos , Hemorragia/terapia , Ferimentos e Lesões/terapia , Feminino , Humanos , Londres , Masculino
10.
Br J Surg ; 103(4): 357-65, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26841720

RESUMO

BACKGROUND: The aim of this study was to describe the prevalence, patterns of blood use and outcomes of major haemorrhage in trauma. METHODS: This was a prospective observational study from 22 hospitals in the UK, including both major trauma centres and smaller trauma units. Eligible patients received at least 4 units of packed red blood cells (PRBCs) in the first 24 h of admission with activation of the massive haemorrhage protocol. Case notes, transfusion charts, blood bank records and copies of prescription/theatre charts were accessed and reviewed centrally. Study outcomes were: use of blood components, critical care during hospital stay, and mortality at 24 h, 30 days and 1 year. Data were used to estimate the national trauma haemorrhage incidence. RESULTS: A total of 442 patients were identified during a median enrolment interval of 20 (range 7-24) months. Based on this, the national incidence of trauma haemorrhage was estimated to be 83 per million. The median age of patients in the study cohort was 38 years and 73·8 per cent were men. The incidence of major haemorrhage increased markedly in patients aged over 65 years. Thirty-six deaths within 24 h of admission occurred within the first 3 h. At 24 h, 79 patients (17·9 per cent) had died, but mortality continued to rise even after discharge. Patients who received a cumulative ratio of fresh frozen plasma to PRBCs of at least 1 : 2 had lower rates of death than those who received a lower ratio. There were delays in administration of blood. Platelets and cryoprecipitate were either not given, or transfused well after initial resuscitation. CONCLUSION: There is a high burden of trauma haemorrhage that affects all age groups. Research is required to understand the reasons for death after the first 24 h and barriers to timely transfusion support.


Assuntos
Transfusão de Sangue/normas , Transfusão de Sangue/tendências , Cuidados Críticos/métodos , Hemorragia/mortalidade , Traumatismo Múltiplo/mortalidade , Centros de Traumatologia , Adulto , Estudos Transversais , Inglaterra/epidemiologia , Feminino , Seguimentos , Hemorragia/etiologia , Hemorragia/terapia , Mortalidade Hospitalar/tendências , Humanos , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Traumatismo Múltiplo/complicações , Estudos Prospectivos , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
11.
Br J Surg ; 102(11): 1314-24, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26349842

RESUMO

BACKGROUND: Numerous published studies have explored associations between anaemia and adverse outcomes after surgery. However, there are no evidence syntheses describing the impact of preoperative anaemia on postoperative outcomes. METHODS: A systematic review and meta-analysis of observational studies exploring associations between preoperative anaemia and postoperative outcomes was performed. Studies investigating trauma, burns, transplant, paediatric and obstetric populations were excluded. The primary outcome was 30-day or in-hospital mortality. Secondary outcomes were acute kidney injury, stroke and myocardial infarction. Predefined analyses were performed for the cardiac and non-cardiac surgery subgroups. A post hoc analysis was undertaken to evaluate the relationship between anaemia and infection. Data are presented as odds ratios (ORs) with 95 per cent c.i. RESULTS: From 8973 records, 24 eligible studies including 949 445 patients were identified. Some 371 594 patients (39·1 per cent) were anaemic. Anaemia was associated with increased mortality (OR 2·90, 2·30 to 3·68; I(2) = 97 per cent; P < 0·001), acute kidney injury (OR 3·75, 2·95 to 4·76; I(2) = 60 per cent; P < 0·001) and infection (OR 1·93, 1·17 to 3·18; I(2) = 99 per cent; P = 0·01). Among cardiac surgical patients, anaemia was associated with stroke (OR 1·28, 1·06 to 1·55; I(2) = 0 per cent; P = 0·009) but not myocardial infarction (OR 1·11, 0·68 to 1·82; I(2) = 13 per cent; P = 0·67). Anaemia was associated with an increased incidence of red cell transfusion (OR 5·04, 4·12 to 6·17; I(2) = 96 per cent; P < 0·001). Similar findings were observed in the cardiac and non-cardiac subgroups. CONCLUSION: Preoperative anaemia is associated with poor outcomes after surgery, although heterogeneity between studies was significant. It remains unclear whether anaemia is an independent risk factor for poor outcome or simply a marker of underlying chronic disease. However, red cell transfusion is much more frequent amongst anaemic patients.


Assuntos
Anemia/complicações , Mortalidade Hospitalar , Complicações Pós-Operatórias/mortalidade , Anemia/terapia , Transfusão de Sangue/estatística & dados numéricos , Humanos , Modelos Estatísticos , Razão de Chances , Complicações Pós-Operatórias/etiologia , Período Pré-Operatório , Fatores de Risco
12.
Transfus Med ; 25(1): 27-32, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25807860

RESUMO

BACKGROUND: The prevalence of anaemia in pregnancy in Europe is 25% and that resulting from iron deficiency is estimated at 40%. The maternal and fetal morbidity of non-anaemic iron deficiency (NAID) in pregnancy is likely to be significant. OBJECTIVES: To determine the views and opinions of health service users and clinicians concerning NAID in pregnancy in order to inform future research. METHODS: Two semi-structured focus groups were carried out to determine health service users' views on anaemia and NAID in pregnancy. A questionnaire was administered to obstetricians, haematologists, midwives and anaesthetists to elucidate their views on NAID in pregnancy. RESULTS: The study indicated that health service users and clinicians were interested in implementing testing for NAID in pregnancy with serum ferritin, if proven to be effective at reducing the effects of anaemia and improving maternal and neonatal outcomes. Clinicians had reservations in the use of intravenous iron supplementation for NAID in pregnancy. CONCLUSION: NAID is now accepted as a target condition for research by health service users and clinicians. The focus of future research should be on screening for NAID and its treatment.


Assuntos
Ferritinas/sangue , Deficiências de Ferro , Médicos , Complicações Hematológicas na Gravidez/epidemiologia , Complicações Hematológicas na Gravidez/terapia , Inquéritos e Questionários , Adulto , Atenção à Saúde , Feminino , Humanos , Ferro/sangue , Gravidez , Complicações Hematológicas na Gravidez/sangue
13.
Anaesthesia ; 70 Suppl 1: 3-9, e2, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25440389

RESUMO

The clinical practice of blood transfusion has changed considerably over the last few decades. The potential risk of transfusion transmissible diseases has directed efforts towards the production of safe and high quality blood. All transfusion services now operate in an environment of ever-increasing regulatory controls encompassing all aspects of blood collection, processing and storage. Stringent donor selection, identification of pathogens that can be transmitted through blood, and development of technologies that can enhance the quality of blood, have all led to a substantial reduction in potential risks and complications associated with blood transfusion. In this article, we will discuss the current standards required for the manufacture of blood, starting from blood collection, through processing and on to storage.


Assuntos
Bancos de Sangue , Incompatibilidade de Grupos Sanguíneos/diagnóstico , Preservação de Sangue , Coleta de Amostras Sanguíneas , Doadores de Sangue , Transfusão de Sangue , Humanos , Procedimentos de Redução de Leucócitos
15.
Phys Chem Chem Phys ; 16(20): 9556-64, 2014 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-24727793

RESUMO

Conjugated polymer-semiconductor quantum dot (QD) composites are attracting increasing attention due to the complementary properties of the two classes of materials. We report a convenient method for in situ formation of QDs, and explore the conditions required for light emission of nanocomposite blends. In particular we explore the properties of nanocomposites of the blue emitting polymer poly[9,9-bis(3,5-di-tert-butylphenyl)-9H-fluorene] together with cadmium sulphide (CdS) and cadmium selenide (CdSe) precursors. We show the formation of emissive quantum dots of CdSe from thermally decomposed precursor. The dots are formed inside the polymer matrix and have a photoluminescence quantum yield of 7.5%. Our results show the importance of appropriate energy level alignment, and are relevant to the application of organic-inorganic systems in optoelectronic devices.

16.
Transfus Med ; 24(3): 145-53, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24750387

RESUMO

The Olympics is one of the largest sporting events in the world. Major events may be complicated by disruption of normal activity and major incidents. Health care and transfusion planners should be prepared for both. Previously, transfusion contingency planning has focused on seasonal blood shortages and pandemic influenzas. This article is the first published account of transfusion contingency planning for a major event. We describe the issues encountered and the lessons identified during transfusion planning for the London 2012 Olympics. Planning was started 18 months in advance and was led by a project team reporting to the Executive. Planning was based on three periods of Gamestime. The requirements were planned with key stakeholders using normal processes enhanced by service developments. Demand planning was based on literature review together with computer modelling. The aim was blood-stock sufficiency complimented by a high readiness donor panel to minimise waste. Plans were widely communicated and table-top exercised. Full transfusion services were maintained during both Games with all demands met. The new service improvements and high readiness donors worked well. Emergency command and control have been upgraded. Red cell concentrate (RCC) stock aged but wastage was not significantly increased. The key to success was: early planning, stakeholder engagement, service developments, integration of transfusion service planning within the wider health care community and conduct within an assurance framework.


Assuntos
Armazenamento de Sangue , Bancos de Sangue , Preservação de Sangue , Implementação de Plano de Saúde , Medicina Esportiva , Esportes , Bancos de Sangue/história , Bancos de Sangue/organização & administração , Implementação de Plano de Saúde/história , Implementação de Plano de Saúde/métodos , Implementação de Plano de Saúde/estatística & dados numéricos , História do Século XXI , Humanos , Londres , Medicina Esportiva/história , Medicina Esportiva/métodos , Medicina Esportiva/organização & administração , Armazenamento de Sangue/métodos
17.
Hernia ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38722398

RESUMO

PURPOSE: Use of mesh is essential in hernia repair. A common complication after hernia repair is surgical site infection (SSI), which poses a risk in spreading to the mesh, possibly causing mesh infection. Topical antimicrobial pretreatment of mesh may potentially reduce SSI risk in hernia repair and has shown promising results in in vitro and in vivo studies. Clinical evidence, however, is more important. This systematic review aims to provide an overview of available clinical evidence for antimicrobial pretreated mesh in hernia repair surgery to reduce SSI. METHODS: We report in accordance with PRISMA guidelines. CENTRAL, EMBASE, CINAHL and PubMed were searched up to October 2023 for studies that investigated the use of antimicrobial pretreated mesh on SSI incidence in adults undergoing hernia repair. The primary outcome was SSI incidence. We also collected data on pathogen involvement, hernia recurrence, and mesh infection. A meta-analysis on SSI risk and GRADE-assessment was performed of eligible studies. RESULTS: We identified 11 eligible studies (n = 2660 patients); 5 randomized trials and 6 cohort studies. Investigated interventions included pre-coated mesh, antibiotic carriers, mesh soaked or irrigated with antibiotic or antiseptic solution. Meta-analysis showed no significant reduction in SSI for antibiotic pretreated polypropylene mesh (RR 0.76 [95% CI 0.27; 2.09]; I2 50%). CONCLUSION: Data on topical mesh pretreatment to reduce SSI risk after hernia repair is limited. Very low certainty evidence from randomized trials in hernia repair surgery shows no significant benefit for antibiotic mesh pretreatment for SSI reduction, but data are imprecise due to optimal information size not being met.

18.
Am J Transplant ; 13(6): 1594-600, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23617703

RESUMO

Passenger lymphocyte syndrome (PLS) is an immune-mediated hemolysis. It occurs following ABO blood group mismatched solid organ and/or bone marrow transplantation between donor and recipient. We report two cases of PLS occurring after renal transplantation. Both recipients received live related kidney transplants; one from his mother and the other from his brother. The direction of blood group transfer, from donor to recipient, was O Rh D+ to A Rh D+ in both cases. Approximately 12 days after transplantation, both recipients showed a rapid fall in their hemoglobin levels with no identifiable bleeding source. DAT positive hemolysis was confirmed and anti-A antibodies were detected in recipient sera, confirming a diagnosis of PLS. Both cases required blood transfusion support to maintain their hemoglobin and both had good renal outcomes. We have identified 99 PLS cases following renal transplant in the English literature. Previous ABO sensitization, donor blood group O to recipient blood group A or B transfer, and ciclosporin treatment have been identified as risk factors for PLS. Clinical outcomes in general are good; nonetheless, cases of graft failure and deaths have been reported. Early diagnosis and appropriate treatment are important in at risk individuals.


Assuntos
Sistema ABO de Grupos Sanguíneos/imunologia , Anemia Hemolítica Autoimune/imunologia , Incompatibilidade de Grupos Sanguíneos/complicações , Transplante de Rim/efeitos adversos , Adulto , Anemia Hemolítica Autoimune/etiologia , Anemia Hemolítica Autoimune/terapia , Incompatibilidade de Grupos Sanguíneos/imunologia , Transfusão de Sangue/métodos , Seguimentos , Humanos , Falência Renal Crônica/cirurgia , Transplante de Rim/imunologia , Transplante de Rim/instrumentação , Masculino , Síndrome , Transplante Homólogo , Adulto Jovem
20.
Environ Sci Technol ; 47(15): 8716-23, 2013 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-23859083

RESUMO

The oxidation of dissolved manganese(II) (Mn(II)) during chlorination is a relatively slow process which may lead to residual Mn(II) in treated drinking waters. Chemical Mn(II) oxidation is autocatalytic and consists of a homogeneous and a heterogeneous process; the oxidation of Mn(II) is mainly driven by the latter process. This study demonstrates that Mn(II) oxidation during chlorination is enhanced in bromide-containing waters by the formation of reactive bromine species (e.g., HOBr, BrCl, Br2O) from the oxidation of bromide by chlorine. During oxidation of Mn(II) by chlorine in bromide-containing waters, bromide is recycled and acts as a catalyst. For a chlorine dose of 1 mg/L and a bromide level as low as 10 µg/L, the oxidation of Mn(II) by reactive bromine species becomes the main pathway. It was demonstrated that the kinetics of the reaction are dominated by the adsorbed Mn(OH)2 species for both chlorine and bromine at circumneutral pH. Reactive bromine species such as Br2O and BrCl significantly influence the rate of manganese oxidation and may even outweigh the reactivity of HOBr. Reaction orders in [HOBr]tot were found to be 1.33 (±0.15) at pH 7.8 and increased to 1.97 (±0.17) at pH 8.2 consistent with an important contribution of Br2O which is second order in [HOBr]tot. These findings highlight the need to take bromide, and the subsequent reactive bromine species formed upon chlorination, into account to assess Mn(II) removal during water treatment with chlorine.


Assuntos
Brometos/química , Cloro/química , Manganês/química , Catálise , Cinética , Oxirredução
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA