RESUMO
In sub-Saharan Africa, acute-onset severe malaria anaemia (SMA) is a critical challenge, particularly affecting children under five. The acute drop in haematocrit in SMA is thought to be driven by an increased phagocytotic pathological process in the spleen, leading to the presence of distinct red blood cells (RBCs) with altered morphological characteristics. We hypothesized that these RBCs could be detected systematically and at scale in peripheral blood films (PBFs) by harnessing the capabilities of deep learning models. Assessment of PBFs by a microscopist does not scale for this task and is subject to variability. Here we introduce a deep learning model, leveraging a weakly supervised Multiple Instance Learning framework, to Identify SMA (MILISMA) through the presence of morphologically changed RBCs. MILISMA achieved a classification accuracy of 83% (receiver operating characteristic area under the curve [AUC] of 87%; precision-recall AUC of 76%). More importantly, MILISMA's capabilities extend to identifying statistically significant morphological distinctions (p < 0.01) in RBCs descriptors. Our findings are enriched by visual analyses, which underscore the unique morphological features of SMA-affected RBCs when compared to non-SMA cells. This model aided detection and characterization of RBC alterations could enhance the understanding of SMA's pathology and refine SMA diagnostic and prognostic evaluation processes at scale.
Assuntos
Anemia , Aprendizado Profundo , Eritrócitos , Humanos , Eritrócitos/patologia , Anemia/sangue , Anemia/patologia , Anemia/diagnóstico , Feminino , Masculino , Pré-Escolar , Malária/sangue , Malária/diagnóstico , Malária/patologia , Lactente , CriançaRESUMO
Blood transfusion is an important treatment modality for severe anaemia. Monitoring post-transfusion haemoglobin (Hb) concentration helps the clinician in assessing the success of blood transfusion. Previous authors have reported different timings for post-transfusion equilibration using varied time intervals for post-transfusion Hb concentration assessment. This study was therefore aimed at determining the appropriate time to assess Hb concentration after packed red blood cell (pRBC) transfusion in children using 5 different time intervals. It was a longitudinal observational study carried out in a tertiary care hospital in Southeast, Nigeria and involved 108 children aged 1-10 years without active bleeding or significant haemolysis that were transfused with pRBC. The Hb concentration was measured using a portable haemoglobinometer just before the blood transfusion and after the blood transfusion at 1, 6, 12, 24, and 48th-hour. The 1-hour (6.8 ± 1.5 g/dl) post-transfusion Hb concentration was significantly different (p 0.001) from the 6th-hour (10.2 ± 1.5 g/dl), but no further significant (p > 0.05) changes occurred after the 6th-hour till the 48th-hour. This finding suggests that equilibration of Hb concentration had occurred by the 6th hour after blood transfusion. This study, therefore, recommends that Hb concentration assessment in children without ongoing bleeding or haemolysis can be done at the 6th hour after pRBC transfusion.
Assuntos
Transfusão de Eritrócitos , Hemólise , Humanos , Criança , Centros de Atenção Terciária , Nigéria , Serviço Hospitalar de Emergência , Hemoglobinas/análiseRESUMO
Automated image-based assessment of blood films has tremendous potential to support clinical haematology within overstretched healthcare systems. To achieve this, efficient and reliable digital capture of the rich diagnostic information contained within a blood film is a critical first step. However, this is often challenging, and in many cases entirely unfeasible, with the microscopes typically used in haematology due to the fundamental trade-off between magnification and spatial resolution. To address this, we investigated three state-of-the-art approaches to microscopic imaging of blood films which leverage recent advances in optical and computational imaging and analysis to increase the information capture capacity of the optical microscope: optical mesoscopy, which uses a giant microscope objective (Mesolens) to enable high-resolution imaging at low magnification; Fourier ptychographic microscopy, a computational imaging method which relies on oblique illumination with a series of LEDs to capture high-resolution information; and deep neural networks which can be trained to increase the quality of low magnification, low resolution images. We compare and contrast the performance of these techniques for blood film imaging for the exemplar case of Giemsa-stained peripheral blood smears. Using computational image analysis and shape-based object classification, we demonstrate their use for automated analysis of red blood cell morphology and visualization and detection of small blood-borne parasites such as the malarial parasite Plasmodium falciparum. Our results demonstrate that these new methods greatly increase the information capturing capacity of the light microscope, with transformative potential for haematology and more generally across digital pathology. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
Assuntos
Sangue/diagnóstico por imagem , Diagnóstico por Imagem/métodos , Aprendizado de Máquina , Microscopia/métodos , HumanosRESUMO
BACKGROUND: Primary stroke prevention programmes for children with sickle cell disease (SCD) have been shown to be feasible interventions in resource-poor countries. Different hydroxyurea (HU) regimens have been utilised in ameliorating the severity of SCD. OBJECTIVE: To determine the long-term outcomes of the stroke prevention programme for children with SCD in Ibadan (SPPIBA), Nigeria. METHODS: A longitudinal study of 396 children with haemoglobin SS disease who had been on the stroke prevention programme for a minimum period of 5 years. All enrollees had nonimaging TCD performed at baseline and thereafter 3-monthly or annually. Children with TCD velocities ≥170 cm/s were treated with HU by dose-escalation regimen. RESULTS: The mean age at first TCD examination was 102 ± 46.7 months and the period of follow-up ranged from 5 to 10 years (mean = 7.2 ± 1.7). Time to significant decline in TCD velocities ranged from 5 to 35 months, (median = 10.0 months). The minimum dose of HU required to achieve significant decline in TCD velocities ranged from 15 to 31 mg/kg/day, mean 23.7 (±3.9). HU dose escalation beyond 20 mg/kg/day was required to attain significant reductions in the time-averaged mean of maximal velocities (TAMMV) in 69.1% of the cases. Two stroke events occurred giving a stroke incidence of 0.08 per 100 patient-years. CONCLUSION: The majority of Nigerian children with SCD and elevated TCD velocities achieved significant decline in TAMMV within the first year of HU therapy but on higher doses of HU. It might be important to individualise HU doses for optimal outcomes in primary stroke prevention.
Assuntos
Anemia Falciforme/tratamento farmacológico , Antidrepanocíticos/uso terapêutico , Hidroxiureia/uso terapêutico , Acidente Vascular Cerebral/prevenção & controle , Adolescente , Anemia Falciforme/complicações , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Estudos Longitudinais , Masculino , Nigéria/epidemiologia , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/etiologia , Ultrassonografia Doppler TranscranianaRESUMO
The objectives of this study were to describe the clinicopathologic features and treatment outcomes of childhood rhabdomyosarcoma in a resource-constrained setting. All cases of childhood rhabdomyosarcoma seen over a 10-year period (July 2006 to June 2016) at the University College Hospital, Ibadan, Nigeria were reviewed. Data were extracted from the database of the pediatric Hematology/Oncology Unit of the hospital and analyzed. Ethical approval was obtained from the Institutional Ethics Committee. Fifty children were seen comprising 30 men and 20 women with bimodal ages of 4 and 5 years. Median duration of illness was 16 weeks and the most common primary tumor site was the head-and-neck region in 27 (54%) of cases. The histologic subtypes were embryonal in 30 (60%), alveolar in 9 (18%), and not specified in 11 (22%). The Intergroup Rhabdomyosarcoma Study group TNM Pretreatment stages were stage I in 15 (30%), stage III in 17 (34%), and stage IV in 18 (36%). Treatment included chemotherapy, surgery, and radiotherapy and abandoned in 20 (40%) cases. Median survival was 45 weeks (95% confidence interval: 16.4-73.6) and 5 (10%) patients were alive and disease free, 4 years or more after diagnosis. Outcome of childhood rhabdomyosarcoma is poor and early diagnosis and improved access to treatment are recommended.
Assuntos
Neoplasias de Cabeça e Pescoço/terapia , Rabdomiossarcoma/terapia , Pré-Escolar , Gerenciamento Clínico , Feminino , Neoplasias de Cabeça e Pescoço/epidemiologia , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Nigéria/epidemiologia , Estudos Retrospectivos , Rabdomiossarcoma/epidemiologia , Rabdomiossarcoma/patologia , Resultado do TratamentoRESUMO
AIM: To describe the pattern of paediatric Rhabdomyosarcomas (RMS) and Non-Rhabdomyosarcomas (NRMS) with emphasis on the indices that affect survival outcomes. METHODS: We reviewed all patients with histologically confirmed RMS and NRMS in the Departments of Pathology and Paediatrics, University College Hospital (UCH), Ibadan, Nigeria; in children aged 0-14 years. The study period was January 1991 to December 2016. Information obtained included age, gender, morphology and site of the tumours. The tumour grade and pathologic/clinical staging of all patients were also obtained and verified by the clinical records. Tumour grading was carried out using the Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) Sarcoma group grading system and staging was done using TNM. Follow up, survival information and final outcome were retrieved. RESULTS: The 104 patients included in the study had almost equal male-to-female ratio, age ranged between 5 months and 14 years (median 8.2 years). Rhabdomyosarcoma had mean age of 5.6 (±3.8) years while that of NRMS was 9.2(±4.1) years. Overall, the modal age group was 5-9 years. Rhabdomyosarcoma was the commonest histological type (76%), undifferentiated sarcomas (6.7%), fibrosarcoma (3.8%) and 2.9% each for synovial sarcoma and dermatofibrosarcoma protuberans. The common primary sites were the head and neck (including the orbit) 49 (47.1%), and the abdominopelvic 26 (25%) regions. Majority (89%) had histologic grade 3 at presentation. Seventy per cent and 64% of patients with RMS and NRMS, respectively, had high stage tumour at presentation. Median survival for all patients with Rhabdomyosarcoma was 45 weeks with a 1-year survival of 43% and 2-year survival of 25%. Non-RMS (Dermatofibrosarcoma protuberans and Solitary fibrous tumours) had survival of over 4 year's duration. CONCLUSION: Majority of our patients presented at a late stage with histologic high grade which confers poor prognosis and reduced chances for good overall survival outcome.
Assuntos
Rabdomiossarcoma , Sarcoma , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Nigéria , Prognóstico , Estudos Retrospectivos , Rabdomiossarcoma/terapiaRESUMO
Sickle cell disease is a genetic disease with a predisposition to infections caused by encapsulated organisms, especially Streptococcus pneumoniae. Pneumococcal vaccines and prophylactic penicillin have reduced the rate of this infection and mortality in sickle cell disease. However, implementation of these interventions is limited in Africa. The objectives of the study were to assess health care providers' behaviors with the implementation of pneumococcal vaccination and penicillin prophylaxis and to identify barriers to their use. A 25-item online questionnaire was administered through SickleinAfrica: a network of researchers, and healthcare providers, in Ghana, Nigeria, and Tanzania, working to improve health outcomes of sickle cell disease in Africa. Data was collected and managed using the Research Electronic Data Capture (REDCap), tools and data analysis was done using STATA version 13 and R statistical software. Eighty-two medical practitioners responded to the questionnaire. Only 54.0 and 48.7% of respondents indicated the availability of published guidelines on sickle cell disease management and pneumococcal vaccine use, respectively, at their facilities. The majority (54.0%) perceived that the vaccines are effective but over 20.0% were uncertain of their usefulness. All respondents from Ghana and Tanzania affirmed the availability of guidelines for penicillin prophylaxis in contrast to 44.1% in Nigeria. Eighty-five percent of respondents affirmed the need for penicillin prophylaxis but 15.0% had a contrary opinion for reasons including the rarity of isolation of Streptococcus pneumoniae in African studies, and therefore, the uncertainty of its benefit. Lack of published guidelines on the management of sickle cell disease and doubts about the necessity of prophylactic measures are potential barriers to the implementation of effective interventions.
Assuntos
Anemia Falciforme , Penicilinas , Infecções Pneumocócicas , Vacinas Pneumocócicas/uso terapêutico , Anemia Falciforme/complicações , Pessoal de Saúde , Humanos , Nigéria , Penicilinas/uso terapêutico , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/etiologia , Infecções Pneumocócicas/prevenção & controle , Streptococcus pneumoniaeRESUMO
BACKGROUND: Cerebral malaria (CM), is a life-threatening childhood malaria syndrome with high mortality. CM is associated with impaired consciousness and neurological damage. It is not fully understood, as yet, why some children develop CM. Presented here is an observation from longitudinal studies on CM in a paediatric cohort of children from a large, densely-populated and malaria holoendemic, sub-Saharan, West African metropolis. METHODS: Plasma samples were collected from a cohort of children with CM, severe malarial anaemia (SMA), uncomplicated malaria (UM), non-malaria positive healthy community controls (CC), and coma and anemic patients without malaria, as disease controls (DC). Proteomic two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry were used in a discovery cohort to identify plasma proteins that might be discriminatory among these clinical groups. The circulatory levels of identified proteins of interest were quantified by ELISA in a prospective validation cohort. RESULTS: The proteome analysis revealed differential abundance of circulatory complement-lysis inhibitor (CLI), also known as Clusterin (CLU). CLI circulatory level was low at hospital admission in all children presenting with CM and recovered to normal level during convalescence (p < 0.0001). At acute onset, circulatory level of CLI in the CM group significantly discriminates CM from the UM, SMA, DC and CC groups. CONCLUSIONS: The CLI circulatory level is low in all patients in the CM group at admission, but recovers through convalescence. The level of CLI at acute onset may be a specific discriminatory marker of CM. This work suggests that CLI may play a role in the pathophysiology of CM and may be useful in the diagnosis and follow-up of children presenting with CM.
Assuntos
Clusterina/sangue , Convalescença , Malária Cerebral/parasitologia , Malária Falciparum/parasitologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Malária Cerebral/sangue , Malária Falciparum/sangue , Masculino , Estudos ProspectivosRESUMO
Over 200 million malaria cases globally lead to half a million deaths annually. Accurate malaria diagnosis remains a challenge. Automated imaging processing approaches to analyze Thick Blood Films (TBF) could provide scalable solutions, for urban healthcare providers in the holoendemic malaria sub-Saharan region. Although several approaches have been attempted to identify malaria parasites in TBF, none have achieved negative and positive predictive performance suitable for clinical use in the west sub-Saharan region. While malaria parasite object detection remains an intermediary step in achieving automatic patient diagnosis, training state-of-the-art deep-learning object detectors requires the human-expert labor-intensive process of labeling a large dataset of digitized TBF. To overcome these challenges and to achieve a clinically usable system, we show a novel approach. It leverages routine clinical-microscopy labels from our quality-controlled malaria clinics, to train a Deep Malaria Convolutional Neural Network classifier (DeepMCNN) for automated malaria diagnosis. Our system also provides total Malaria Parasite (MP) and White Blood Cell (WBC) counts allowing parasitemia estimation in MP/µL, as recommended by the WHO. Prospective validation of the DeepMCNN achieves sensitivity/specificity of 0.92/0.90 against expert-level malaria diagnosis. Our approach PPV/NPV performance is of 0.92/0.90, which is clinically usable in our holoendemic settings in the densely populated metropolis of Ibadan. It is located within the most populous African country (Nigeria) and with one of the largest burdens of Plasmodium falciparum malaria. Our openly available method is of importance for strategies aimed to scale malaria diagnosis in urban regions where daily assessment of thousands of specimens is required.
Assuntos
Malária Falciparum/sangue , Malária/diagnóstico , Redes Neurais de Computação , Humanos , Malária/sangueRESUMO
Sickle cell disease affects about 150,000 births annually in Nigeria. Early diagnosis is hampered by factors such as centralized and urban localization of laboratories, high cost of diagnostic equipment and inadequate skilled manpower to operate them. The need for a low-cost, portable, easy-to-use diagnostic test for sickle cell disease is critical, especially in resource-poor countries. In this study, we evaluated the performance characteristics of a novel point-of-care testing device (SickleSCAN™), and its acceptability and feasibility, as a possible screening tool for sickle cell disease. In the first phase, we assessed the performance characteristics of SickleSCAN™ by evaluating 57 subjects comprising both children and adults attending a primary health center, for Hb SS (ßS/ßS; HBB: c.20A>T), Hb SC (ßS/ßC; HBB: c.19G>A) and Hb AS (ßA/ßS) using SickleSCAN™, cellulose acetate electrophoresis (CAE) and high performance liquid chromatography (HPLC). Performance characteristics such as diagnostic sensitivity and specificity were compared to HPLC as a standard method. We subsequently undertook a second phase wherein the acceptability and feasibility of the device for sickle cell disease screening, was evaluated using semi-structured and structured questionnaires among 197 healthcare personnel and 221 subjects, respectively. Sickle cell disease was carried by 3.4% of the subjects. The diagnostic sensitivity, specificity and test efficiency of SickleSCAN™ for sickle cell disease (Hb SS and Hb SC), were 100.0, 98.2 and 98.2%, respectively. Findings from this study showed SickleSCAN™ to be a viable screening tool that can easily be applied in community-based screening for early diagnosis of sickle cell disease with little expertise and low cost.
Assuntos
Anemia Falciforme/diagnóstico , Hemoglobina Falciforme/análise , Sistemas Automatizados de Assistência Junto ao Leito , Adolescente , Adulto , Anemia Falciforme/sangue , Criança , Pré-Escolar , Eletroforese em Acetato de Celulose/instrumentação , Eletroforese em Acetato de Celulose/métodos , Feminino , Hemoglobina Falciforme/metabolismo , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
Cerebral malaria (CM) is a neurological complication of infection with Plasmodium falciparum that is partly caused by cytokine-mediated inflammation. It is not known whether interleukin-17 (IL-17) cytokines, which regulate inflammation, control the development of CM. To evaluate the involvement of IL-17 cytokines in CM, we analyzed 46 common polymorphisms in IL17A, IL17F, and IL17RA (which encodes the common receptor chain of the members of the IL-17 family) in two independent African populations. A case-control study involving 115 Nigerian children with CM and 160 controls from the community (CC) showed that IL17F reference single nucleotide polymorphism (SNP) 6913472 (rs6913472) (P = 0.004; odds ratio [OR] = 3.12), IL17F rs4715291 (P = 0.004; OR = 2.82), IL17RA rs12159217 (P = 0.01; OR = 2.27), and IL17RA rs41396547 (P = 0.026; OR = 3.15) were independently associated with CM. A replication study was performed in 240 nuclear Malian family trios (two parents with one CM child). We replicated the association for 3 SNPs, IL17F rs6913472 (P = 0.03; OR = 1.39), IL17RA rs12159217 (P = 0.01; OR = 1.52), and IL17RA rs41396547 (P = 0.04; OR = 3.50). We also found that one additional SNP, IL17RA rs41433045, in linkage disequilibrium (LD) with rs41396547, was associated with CM in both Nigeria and Mali (P = 0.002; OR = 4.12 in the combined sample). We excluded the possibility that SNPs outside IL17F and IL17RA, in strong LD with the associated SNPs, could account for the observed associations. Furthermore, the results of a functional study indicated that the aggravating GA genotype of IL17F rs6913472 was associated with lower IL-17F concentrations. Our findings show for the first time that IL17F and IL17RA polymorphisms modulate susceptibility to CM and provide evidence that IL-17F protects against CM.
Assuntos
Interleucina-17/genética , Malária Cerebral/etnologia , Malária Cerebral/genética , Polimorfismo de Nucleotídeo Único , Receptores de Interleucina-17/genética , Adolescente , África/epidemiologia , Criança , Pré-Escolar , Simulação por Computador , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Genética Populacional , Genótipo , Humanos , Lactente , Interleucina-17/imunologia , Desequilíbrio de Ligação , Malária Cerebral/epidemiologia , Malária Cerebral/imunologia , Masculino , Receptores de Interleucina-17/imunologiaRESUMO
Systemic inflammation and sequestration of parasitized erythrocytes are central processes in the pathophysiology of severe Plasmodium falciparum childhood malaria. However, it is still not understood why some children are more at risks to develop malaria complications than others. To identify human proteins in plasma related to childhood malaria syndromes, multiplex antibody suspension bead arrays were employed. Out of the 1,015 proteins analyzed in plasma from more than 700 children, 41 differed between malaria infected children and community controls, whereas 13 discriminated uncomplicated malaria from severe malaria syndromes. Markers of oxidative stress were found related to severe malaria anemia while markers of endothelial activation, platelet adhesion and muscular damage were identified in relation to children with cerebral malaria. These findings suggest the presence of generalized vascular inflammation, vascular wall modulations, activation of endothelium and unbalanced glucose metabolism in severe malaria. The increased levels of specific muscle proteins in plasma implicate potential muscle damage and microvasculature lesions during the course of cerebral malaria.
Assuntos
Malária Cerebral/sangue , Estresse Oxidativo , Plasmodium falciparum , Proteômica/métodos , Adolescente , Biomarcadores/sangue , Criança , Pré-Escolar , Feminino , Humanos , Masculino , SíndromeRESUMO
Iron deficiency remains a global public health challenge, with a higher burden in children in the tropics. When it occurs early in life, it may have long-term effects on neurodevelopment. The aims of this study were to assess the iron status of children aged 6-24 months, to determine the prevalence of iron deficiency and its associated factors in Ibadan, Nigeria. The authors conducted a cross-sectional study between March and June 2014. A total of 202 apparently healthy children aged between 6 and 24 months attending 2 major immunization clinics in Ibadan were included. A questionnaire was used to collect information on sociodemographic characteristics, pregnancy and birth history, and nutritional history. Physical examination was carried out on all the subjects, and serum ferritin level was determined using an enzyme-linked immunosorbent assay (ELISA) technique. Iron deficiency was defined using a cutoff value of <30 µg/L. Fifty-nine children (29.2%) had iron deficiency. No clinical features were found to be significantly associated with iron deficiency. Iron deficiency was associated with breastfeeding (P = .020) and younger age (P = .015) in the study population. One hundred and forty-three (70.8%) of the study participants had anemia, and 39 (19.3%) had iron deficiency anemia. The prevalence of iron deficiency among apparently healthy children aged 6-24 months in Ibadan, Nigeria, is high. There is the need for a national policy on routine screening for iron deficiency and iron supplementation for infants and young children as recommended by the World Health Organization.
Assuntos
Anemia Ferropriva/epidemiologia , Aleitamento Materno , Inquéritos e Questionários , Adulto , Anemia Ferropriva/sangue , Pré-Escolar , Estudos Transversais , Feminino , Ferritinas/sangue , Humanos , Lactente , Masculino , Nigéria , Gravidez , Prevalência , Fatores SocioeconômicosRESUMO
Cerebral malaria (CM) and severe malarial anemia (SMA) are the most serious life-threatening clinical syndromes of Plasmodium falciparum infection in childhood. Therefore, it is important to understand the pathology underlying the development of CM and SMA as opposed to uncomplicated malaria (UM). Increased levels of hepcidin have been associated with UM, but its level and role in severe malarial disease remains to be investigated. Plasma and clinical data were obtained as part of a prospective case-control study of severe childhood malaria at the main tertiary hospital of the city of Ibadan, Nigeria. Here, we report that hepcidin levels are lower in children with SMA or CM than in those with milder outcome (UM). While different profiles of pro- and anti-inflammatory cytokines were observed between the malaria syndromes, circulatory hepcidin levels remained associated with the levels of its regulatory cytokine interleukin-6 and of the anti-inflammatory cytokine inerleukin-10, irrespective of iron status, anemic status, and general acute-phase response. We propose a role for hepcidin in anti-inflammatory processes in childhood malaria.
Assuntos
Peptídeos Catiônicos Antimicrobianos/sangue , Citocinas/sangue , Mediadores da Inflamação/sangue , Malária Cerebral/sangue , Malária Falciparum/sangue , Anemia/sangue , Anemia/complicações , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Ferritinas/sangue , Hematócrito , Hepcidinas , Humanos , Interleucina-10/sangue , Interleucina-6/sangue , Ferro/sangue , Modelos Lineares , Malária Cerebral/complicações , Malária Falciparum/complicações , Masculino , Nigéria , Estudos Prospectivos , Receptores da Transferrina/sangue , Centros de Atenção Terciária , Transferrina/análiseRESUMO
BACKGROUND: Sickle cell anaemia (SCA) is the leading genetic disorder in Nigeria. Elevated velocities ≥170 cm/sec occur in about a third of Nigerian children with SCA. Chronic blood transfusion for stroke prevention is faced with a myriad of challenges in our practice. OBJECTIVES: To evaluate the effectiveness of hydroxyurea (HU) in reducing flow velocities in a cohort of Nigerian children with SCA and elevated velocities treated with HU. METHODS: An observational study was carried out on a cohort of Nigerian children with SCA and elevated velocities identified on routine transcranial Doppler (TCD) screening. HU was recommended in those with TCD velocities ≥ 170cm/sec as stipulated in our hospital protocol. Outcomes were compared after ≥12 months of observation. RESULTS: Fifty children with elevated TCD velocities were studied; 31 consented to HU therapy and 19 declined. Children on HU showed a statistically significant decline in mean velocities from 199.7 [17.1] cm/sec to 165.8 [20.7] cm/sec (P < 0.001) with a significant increase in mean packed cell volume from 21.1 [3.4] to 25.0 [2.8]%. Children without treatment had a significant rise in mean velocities from 190.2 [10.8] cm/sec to 199.7 [14.9] cm/sec (P = 0.003). Children with conditional risk velocities on HU were less likely to convert to abnormal risk (P < 0.001). Two stroke events occurred, one in each group. No adverse effects of HU were recorded in the cohort. CONCLUSION: HU appears to significantly reduce TCD velocities in Nigerian children with SCA and elevated velocities ≥170 cm/sec with beneficial effect on the haematological profile. HU may provide an effective approach to primary stroke prevention, particularly in Africa.
Assuntos
Anemia Falciforme/fisiopatologia , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Circulação Cerebrovascular/efeitos dos fármacos , Hidroxiureia/farmacologia , Ultrassonografia Doppler Transcraniana , Adolescente , Anemia Falciforme/complicações , Anemia Falciforme/tratamento farmacológico , Anemia Falciforme/terapia , Contagem de Células Sanguíneas , Transfusão de Sangue , Artérias Cerebrais/diagnóstico por imagem , Criança , Pré-Escolar , Feminino , Hematócrito , Humanos , Hidroxiureia/uso terapêutico , Masculino , Nigéria , Medição de Risco , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/prevenção & controle , Recusa do Paciente ao TratamentoRESUMO
While optical microscopy inspection of blood films and bone marrow aspirates by a hematologist is a crucial step in establishing diagnosis of acute leukemia, especially in low-resource settings where other diagnostic modalities are not available, the task remains time-consuming and prone to human inconsistencies. This has an impact especially in cases of Acute Promyelocytic Leukemia (APL) that require urgent treatment. Integration of automated computational hematopathology into clinical workflows can improve the throughput of these services and reduce cognitive human error. However, a major bottleneck in deploying such systems is a lack of sufficient cell morphological object-labels annotations to train deep learning models. We overcome this by leveraging patient diagnostic labels to train weakly-supervised models that detect different types of acute leukemia. We introduce a deep learning approach, Multiple Instance Learning for Leukocyte Identification (MILLIE), able to perform automated reliable analysis of blood films with minimal supervision. Without being trained to classify individual cells, MILLIE differentiates between acute lymphoblastic and myeloblastic leukemia in blood films. More importantly, MILLIE detects APL in blood films (AUC 0.94 ± 0.04) and in bone marrow aspirates (AUC 0.99 ± 0.01). MILLIE is a viable solution to augment the throughput of clinical pathways that require assessment of blood film microscopy.
Assuntos
Aprendizado Profundo , Leucemia Mieloide Aguda , Leucemia Promielocítica Aguda , Humanos , Leucemia Promielocítica Aguda/diagnóstico , Leucemia Promielocítica Aguda/patologia , Medula Óssea/patologia , Leucemia Mieloide Aguda/patologia , Testes HematológicosRESUMO
Low-field (<1T) magnetic resonance imaging (MRI) scanners remain in widespread use in low- and middle-income countries (LMICs) and are commonly used for some applications in higher income countries e.g. for small child patients with obesity, claustrophobia, implants, or tattoos. However, low-field MR images commonly have lower resolution and poorer contrast than images from high field (1.5T, 3T, and above). Here, we present Image Quality Transfer (IQT) to enhance low-field structural MRI by estimating from a low-field image the image we would have obtained from the same subject at high field. Our approach uses (i) a stochastic low-field image simulator as the forward model to capture uncertainty and variation in the contrast of low-field images corresponding to a particular high-field image, and (ii) an anisotropic U-Net variant specifically designed for the IQT inverse problem. We evaluate the proposed algorithm both in simulation and using multi-contrast (T1-weighted, T2-weighted, and fluid attenuated inversion recovery (FLAIR)) clinical low-field MRI data from an LMIC hospital. We show the efficacy of IQT in improving contrast and resolution of low-field MR images. We demonstrate that IQT-enhanced images have potential for enhancing visualisation of anatomical structures and pathological lesions of clinical relevance from the perspective of radiologists. IQT is proved to have capability of boosting the diagnostic value of low-field MRI, especially in low-resource settings.
Assuntos
Encéfalo , Meios de Contraste , Criança , Humanos , Encéfalo/patologia , Imageamento por Ressonância Magnética/métodos , Aumento da Imagem/métodos , AlgoritmosRESUMO
Prior to the introduction of the International Network for Cancer Treatment and Research (INCTR) protocol INCTR 03-06, survival of patients with Burkitt lymphoma at four tertiary care centres in equatorial Africa was probably no more than 10-20%. The results reported here for 356 patients have demonstrated marked improvement in survival through the use of a uniform treatment protocol consisting of cyclophosphamide, methotrexate, vincristine, and intrathecal therapy, and the introduction of non-cross resistant second-line (salvage) therapy, consisting of ifosfamide, mesna, etoposide and cytarabine, when patients failed to achieve a complete response to first-line therapy or relapsed early. Overall survival rates of 67% and 62% were observed at 1 and 2 years (relapse is rare after 1 year of remission). Of interest was the small impact of cerebrospinal fluid (CSF) and bone marrow involvement on outcome. However, the presence or absence of abdominal involvement clearly defined two prognostic groups. An additional finding was the association between CSF pleocytosis and orbital tumours, suggesting that spread of tumour cells to the central nervous system may sometimes occur via direct involvement of cranial nerves in the orbit. Survival rates may be increased in patients with abdominal involvement by combining first- and second-line therapy, but verification will require a further clinical study.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linfoma de Burkitt/tratamento farmacológico , Adolescente , Adulto , África Subsaariana/epidemiologia , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Linfoma de Burkitt/diagnóstico , Linfoma de Burkitt/patologia , Causas de Morte , Criança , Pré-Escolar , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Citarabina/administração & dosagem , Citarabina/efeitos adversos , Etoposídeo/administração & dosagem , Etoposídeo/efeitos adversos , Feminino , Seguimentos , Humanos , Ifosfamida/administração & dosagem , Ifosfamida/efeitos adversos , Estimativa de Kaplan-Meier , Masculino , Mesna/administração & dosagem , Mesna/efeitos adversos , Metotrexato/administração & dosagem , Metotrexato/efeitos adversos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Recidiva , Indução de Remissão , Risco , Terapia de Salvação , Taxa de Sobrevida , Resultado do Tratamento , Vincristina/administração & dosagem , Vincristina/efeitos adversos , Adulto JovemRESUMO
BACKGROUND: Haemoglobinuria is one of the manifestations of severe malaria and results from severe intravascular haemolysis. Glucose-6-phosphate dehydrogenase (G6PD) deficiency has been implicated in its aetiology. Haemoglobinuria may be associated with severe anaemia and, less frequently, acute renal failure. METHODS: A prospective case-control study was carried out to determine the incidence of haemoglobinuria as confirmed by dipstick urinalysis, microscopy and spectrophotometric measurement, among children with severe malaria. A total of 251 children presenting at the Children's Emergency Ward with severe malaria were recruited over a period of 21 months. The G6PD status and the outcomes of severe malaria in children with and without haemoglobinuria was studied with respect to renal failure, the recurrence of haemoglobinuria and blood pressure changes over a three-month follow-up period. RESULTS: It was found that the incidence of haemoglobinuria among children with severe malaria is 19.1%. Children <5 years constituted 76.8% of all the study patients. Patients with haemoglobinuria had median age of 52.5 months, which was significantly higher than 35 months in patients without haemoglobinuria (p=0.001). Although, haemaglobinuria was commoner among boys (54.2%) than girls (45.8%), the difference was not statistically significant. There were no significant differences between children with and without haemoglobinuria regarding their nutritional status or parasite densities. Among the clinical features of the study patients, only jaundice was significantly associated with haemoglobinuria (p=0.0001). Renal failure occurred in three out of 48 children with haemoglobinuria and in none of the 203 without. There was not recurrence of haemoglobinuria in the follow-up period. At discharge, blood pressure was elevated in six children (one previously haemoglobinuric), but all returned to normal within the follow-up period. CONCLUSIONS: Haemoglobinuria was a prominent feature of severe malaria and it was significantly associated with jaundice at presentation. Haemoglobinuria was commoner in older children than younger children but not related to sex. G6PD deficiency was not an independent predictor of the occurrence or outcome of haemoglobinuria. Blood pressure was not affected by haemoglobinuria on admission nor during follow-up.
Assuntos
Hemoglobinúria/epidemiologia , Malária/complicações , Malária/epidemiologia , Fatores Etários , Pressão Sanguínea , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Humanos , Incidência , Lactente , Icterícia/epidemiologia , Masculino , Microscopia , Nigéria/epidemiologia , Estudos Prospectivos , Fatores Sexuais , Espectrofotometria , Atenção Terciária à Saúde , Urina/química , Urina/citologiaRESUMO
Automated digital high-magnification optical microscopy is key to accelerating biology research and improving pathology clinical pathways. High magnification objectives with large numerical apertures are usually preferred to resolve the fine structural details of biological samples, but they have a very limited depth-of-field. Depending on the thickness of the sample, analysis of specimens typically requires the acquisition of multiple images at different focal planes for each field-of-view, followed by the fusion of these planes into an extended depth-of-field image. This translates into low scanning speeds, increased storage space, and processing time not suitable for high-throughput clinical use. We introduce a novel content-aware multi-focus image fusion approach based on deep learning which extends the depth-of-field of high magnification objectives effectively. We demonstrate the method with three examples, showing that highly accurate, detailed, extended depth of field images can be obtained at a lower axial sampling rate, using 2-fold fewer focal planes than normally required.