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1.
J Environ Radioact ; 276: 107447, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38749216

RESUMO

Soil is an important source and medium of radionuclides, and the content of radioactivity in soil is crucial for radiological impact evaluation. In this study, twenty soil samples in the high background natural radiation area of Yangjiang, China were collected and analyzed for 226Ra, 232Th, 40K and 137Cs concentrations in order to evaluate the radiological health risk in the area. Results showed that the average activity concentrations of 226Ra, 232Th and 40K are 66 Bq/kg, 109 Bq/kg and 211 Bq/kg, respectively. The calculated radiological parameters of radium equivalent activity (Raeq), absorbed dose rate (D), annual effective dose equivalent (AEDE), internal and external hazard indices (Hin and Hex) show a large variation at different sampling sites. Additionally, the elemental oxidation composition and 40K/K mass ratio in the soil were analyzed to further augment the background information of the high background radiation area in Yangjiang.


Assuntos
Radiação de Fundo , Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos do Solo , Solo , Tório , Poluentes Radioativos do Solo/análise , China , Solo/química , Rádio (Elemento)/análise , Tório/análise , Radioisótopos de Potássio/análise , Radioisótopos de Césio/análise , Oxirredução
2.
J Radiat Res ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38818645

RESUMO

To investigate the levels of 131I activity in thyroid of workers at the place of radioiodine therapy and their main influential factors in China, 341 workers at 38 hospitals performing radioiodine therapy procedure in five provinces were recruited to be measured in 2021. A hand-held gamma spectrometer with NaI(Tl) probe was plastered to the thyroids and thighs of the subjects during the measurement, and each measurement time was 120 s. The internal exposure dose was calculated, and the committed effective dose was estimated. In 86 (25.22%) of the 341 examined workers, 131I thyroid activity was above minimum detectable activity (MDA, 26.6 Bq). The maximum activity was 4.9 × 103 Bq. The detection results above MDA were at 22 (57.89%) different hospitals. The detectable rate for private hospitals (4.8%) was significantly lower than that for public hospitals (26.6%), P < 0.05. The detectable rate for hospitals in provincial capital cities (15.4%) was significantly lower than in nonprovincial capital cities (41.7%), P < 0.001. The detectable rate for hospitals engaged in 131I therapy for thyroid cancer (31.2%) was significantly higher than only for hyperthyroidism (10.3%), P < 0.001. A total of 32 subjects' committed effective dose might exceed 1 mSv. Results indicated the 131I activity in the thyroid of workers at the place of radioiodine varied considerably in China, and mainly related to ownership, location and therapy program of the hospitals.

3.
Appl Radiat Isot ; 206: 111248, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38422940

RESUMO

In this study, to achieve accurate measurement of radioactive noble gas and enhance the precision of efficiency calibration, a relatively low-cost and low-density simulated-gas calibration source (SGCS) was produced from polyurethane foam with a density of ρ = 0.098 g cm-3. Using SGCS with a Marinelli beaker geometry, the efficiency calibration was applied to a BE5030, 50.5% relative efficiency HPGe detector in an energy range of 59.54 keV∼1836.06 keV. Then, taking the 81 keV gamma-ray emitted by 133Xe as an example, due to the density difference between the SGCS and the 133Xe gas sample, it is necessary to correct for self-attenuation effects. Therefore, a semi-empirical function for self-attenuation correction was established by using LabSOCS software and XCOM. Upon validation, the relative deviation of efficiency calibration values between the SGCS and the LabSOCS of 133Xe under the density of 0.001 g cm-3 to 0.01 g cm-3 was about 3%. After using the self-attenuation correction method established in this study, the results verified a good consistency of the efficiency calculated by SGCS and LabSOCS software.

4.
Health Phys ; 126(4): 182-187, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38252031

RESUMO

ABSTRACT: In the absolute measurement method of nuclide radioactivity by the internal gas proportional counter, the reasonable correction of the small pulse counting loss is the key to obtaining the measurement results accurately. Considering the decay type and energy of radioactive gas nuclides, the influence of the low-energy beta particles and the wall effect counting loss on the activity measurement results is different also. To this end, two typical radioactive gas nuclides ( 37 Ar and 3 H) are used to study the cause of counting loss based on the Monte Carlo simulation. The results show that the counting loss of small pulse in the activity measurement of 37 Ar comes mainly from the wall effect generated by x rays. Within the given gas pressure of 60-300 kPa, the simulated wall effect correction factors are 1.063-1.021. The decay energy of ß particles generated by 3 H is very low, and there is no obvious wall effect. The small pulse counting loss mainly comes from the low-energy beta particles' contribution with the energy below the counting threshold, which can be corrected by extrapolating the beta energy spectrum at a lower counting threshold (below 1 keV).


Assuntos
Argônio , Radioisótopos , Método de Monte Carlo , Simulação por Computador , Raios X
5.
Sci Rep ; 12(1): 16676, 2022 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-36202835

RESUMO

Intake of radionuclides and heavy metals through food consumption is one of the important pathways for long-term health considerations. In this paper, the dietary exposure to radionuclides (210Pb, 210Po, 226Ra, 228Ra, 40K, 137Cs and 129I) and heavy metals (As, Hg, Pb, Cd and U) of adult residents in the high background natural radiation area (HBNRA) in Yangjiang, China, was comprehensively assessed using duplicate diet method. The estimated effective dose received by the inhabitants in HBNRA from ingestion of radionuclides was 0.33 mSv/y, and the associated lifetime cancer risk was 1.1 × 10-3. Both the dose and cancer risk to humans were at the acceptable range, and showed no difference between the HBNRA and the control area. With respect to heavy metals, the estimated daily intake of heavy metals (DIM) values for As, Hg, Pb, Cd and U in HBNRA were 0.47, 0.03, 15.0, 0.26 and 0.04 µg/kg bw/d, respectively, and the corresponding target hazard quotient (THQ) were 1.58, 0.09, 3.7, 2.56, 0.18. The DIM and THQ of Cd and U in HBNRA were similar to the control area, but the DIM and THQ of Pb were much higher than the corresponding values of 0.39 and 0.03 in the control area. The hazard index (HI) value of heavy metals in HBNRA was almost twice that of the control area. This suggests that the inhabitants in the HBNRA may have a health risk associated with the heavy metals.


Assuntos
Mercúrio , Metais Pesados , Poluentes do Solo , Adulto , Radiação de Fundo , Cádmio , China , Dieta/efeitos adversos , Exposição Dietética/efeitos adversos , Monitoramento Ambiental , Contaminação de Alimentos/análise , Humanos , Chumbo , Mercúrio/toxicidade , Metais Pesados/efeitos adversos , Metais Pesados/análise , Radioisótopos/efeitos adversos , Medição de Risco , Poluentes do Solo/análise
6.
Environ Int ; 163: 107222, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35378442

RESUMO

Following a radiological or nuclear emergency, workers, responders and the public may be internally contaminated with radionuclides. Screening, monitoring and assessing any internal contamination and providing necessary medical treatment, especially when a large number of individuals are involved, is challenging. Experience gained and lessons learned from the management of previous incidents would help to identify gaps in knowledge and capabilities on preparedness for and response to radiation emergencies. In this paper, eight large-scale and five workplace radiological and nuclear incidents are reviewed cross 14 technical areas, under the broader topics of emergency preparedness, emergency response and recovery processes. The review findings suggest that 1) new strategies, algorithms and technologies are explored for rapid screening of large populations; 2) exposure assessment and dose estimation in emergency response and dose reconstruction in recovery process are supported by complementary sources of information, including 'citizen science'; 3) surge capacity for monitoring and dose assessment is coordinated through national and international laboratory networks; 4) evidence-based guidelines for medical management and follow-up of internal contamination are urgently needed; 5) mechanisms for international and regional access to medical countermeasures are investigated and implemented; 6) long-term health and medical follow up programs are designed and justified; and 7) capabilities and capacity developed for emergency response are sustained through adequate resource allocation, routine non-emergency use of technical skills in regular exercises, training, and continuous improvement.


Assuntos
Planejamento em Desastres , Saúde Pública , Humanos
7.
Front Med (Lausanne) ; 8: 617195, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34322498

RESUMO

Background: Mass drug administration with artemisinin-piperaquine (AP-MDA) is being considered for elimination of residual foci of malaria in Democratic Republic of São Tomé and Principe. Methods: Three monthly rounds of AP-MDA were implemented from July to October 2019. Four zones were selected. A and B were selected as a study site and a control site, respectively. C and D were located within 1.5 and 1.5 km away from the study site, respectively. Parasite prevalence, malaria incidence, and the proportion of the Plasmodium falciparum malaria cases were evaluated. Results: After 3 monthly rounds of AP-MDA, the parasite prevalence and the gametocyte carriage rate of P. falciparum in zone A decreased from 28.29(‰) to 0 and 4.99(‰) to 0, respectively. Compared to zone B, the relative risk for the population with Plasmodium falciparum malaria in zone A was lower (RR = 0.458, 95% CI: 0.146-1.437). Malaria incidence fell from 290.49(‰) (the same period of the previous year) to 15.27(‰) (from the 29th week in 2019 to the 14th week in 2020), a decrease of 94.74% in zone A, and from 31.74 to 5.46(‰), a decline of 82.80% in zone B. Compared to the data of the same period the previous year, the cumulative number of P. falciparum malaria cases were lower, decreasing from 165 to 10 in zone A and from 17 to 4 in zone B. The proportion of the P. falciparum malaria cases on the total malaria cases of the country decreased of 90.16% in zone A and 71.34% in zone C. Conclusion: AP-MDA greatly curbed malaria transmission by reducing malaria incidence in the study site and simultaneously creating a knock-on effect of malaria control within 1.5 km of the study site and within the limited time interval of 38 weeks.

8.
Front Cell Infect Microbiol ; 11: 633905, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34307185

RESUMO

Malaria, one of the most serious parasitic diseases, kills thousands of people every year, especially in Africa. São Tomé and Príncipe are known to have stable transmission of malaria. Indoor residual spraying (IRS) of insecticides and long-lasting insecticidal nets (LLIN) are considered as an effective malaria control interventions in these places. The resistance status of Anopheles gambiae s.s. from Agua Grande, Caue, and Lemba of São Tomé and Príncipe to insecticides, such as dichlorodiphenyltrichloroethane (DDT) (4.0%), deltamethrin (0.05%), permethrin (0.75%), fenitrothion (1.0%), and malathion (5.0%), were tested according to the WHO standard protocol. DNA extraction, species identification, as well as kdr and ace-1R genotyping were done with the surviving and dead mosquitoes post testing. They showed resistance to cypermethrin with mortality rates ranging from 89.06% to 89.66%. Mosquitoes collected from Agua Grande, Caue, and Lemba displayed resistance to DDT and fenitrothion with mortality rates higher than 90%. No other species were detected in these study localities other than Anopheles gambiae s.s. The frequency of L1014F was high in the three investigated sites, which was detected for the first time in São Tomé and Príncipe. No ace-1R mutation was detected in all investigated sites. The high frequency of L1014F showed that kdr L1014F mutation might be related to insecticide resistance to Anopheles gambiae s.s. populations from São Tomé and Príncipe. Insecticide resistance status is alarming and, therefore, future malaria vector management should be seriously considered by the government of São Tomé and Príncipe.


Assuntos
Anopheles , Malária , África , Animais , Anopheles/genética , Humanos , Malária/prevenção & controle , Mosquitos Vetores/genética , Mutação , São Tomé e Príncipe
9.
Health Phys ; 120(5): 552-558, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33350647

RESUMO

ABSTRACT: To study the content of radionuclides in coal and to assess its associated radiological impact on the environment for potential radiological risk assessment, a total of 40 coal samples were collected from various mining areas in eight provinces of China. The specific activities of 226Ra, 232Th, 40K, 210Pb, and 238U were measured in all samples using an HPGe gamma-ray spectrometer, and results were compared with available data from other similar studies. The results reveal that the radium equivalent activity was 74.20 Bq kg-1, external hazard index was 0.20, internal hazard index was 0.27, representative gamma index was 0.52, and indoor and outdoor annual effective dose rates were 0.16 nSv y-1 and 0.04 nSv y-1, respectively. Absorbed gamma dose rate in air was 32.87 nGy h-1. In general, these values are lower than the respective threshold limits recommended by UNSCEAR, and the radiation risk to the public is extremely small.


Assuntos
Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos do Solo , Urânio , Radiação de Fundo , Carvão Mineral , Radioisótopos de Chumbo , Radioisótopos de Potássio/análise , Doses de Radiação , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Tório/análise
10.
Appl Radiat Isot ; 168: 109492, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33129665

RESUMO

Determination of the 131I activity in the thyroid of exposed people or workers is one of the major concerns that needs to be addressed following a nuclear or radiological emergency. International intercomparison exercises on bioassay measurements are one of the effective methods to improve the capability and quality of internal dose assessment. In 2017, Working Group 1 (Internal Dosimetry) of the Asian Radiation Dosimetry Group (ARADOS) organized an intercomparison exercise on the thyroid measurement, aiming at enhancing and coordinating the radiation dosimetry capabilities of Asian countries. This paper describes the measurement experience and results of In Vivo Monitoring Laboratory of NIRP in the 2017 intercomparison exercise, which can provide technical reference for laboratories that have not yet participated in such thyroid measurement intercomparsion. It covers technical aspects such as calibration, measurement and data processing. The results presented in this intercomparison are within an acceptable range of performance criteria on the bioassay measurements. In addition, further research work considered in the field of thyroid measurement is described in the discussion section.


Assuntos
Radioisótopos do Iodo/análise , Radiometria/métodos , Glândula Tireoide/química , Ásia , Calibragem , Humanos , Imagens de Fantasmas , Monitoramento de Radiação/métodos , Espectrometria gama/métodos
11.
Front Pharmacol ; 11: 596697, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33343367

RESUMO

Objective: The purpose of this meta-analysis of longitudinal studies is to determine the safety and efficacy of artesunate combined with other forms of adjunctive therapies for severe malaria. Methods: Following the PRISMA guidelines, we searched multiple databases with the search terms "artesunate" and "adjunctive therapy" and "severe malaria" in July 2020. If the search showed a randomized controlled trial, the study was included in this meta-analysis. The random-effects model was used to calculate the combined incidence rate and relative risk or risk difference. Results: This meta-analysis included nine longitudinal studies with 724 participants. We found that the mortality rates in the artesunate monotherapy group and the artesunate + adjuvant therapy group are similar (RD = -0.02, 95% confidence interval: -0.06-0.02). The incidence of adverse reactions in the artesunate monotherapy group and the artesunate + adjuvant therapy group was also similar. Conclusion: No significant differences in safety and efficacy were observed between the artesunate monotherapy group and the artesunate + adjuvant therapy group. Higher quality and rigorously designed randomized controlled studies are needed to validate our findings.

12.
Front Oncol ; 10: 578763, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33251141

RESUMO

BACKGROUND: Transarterial chemoembolization (TACE) is currently the recommended treatment for intermediate-stage hepatocellular carcinoma (HCC). Liver resection (LR) may be an effective option, although recurrences are not uncommon. TACE prior to LR has been proposed as an even better alternative. METHODS: Patients with intermediate-stage HCC who underwent curative resection were enrolled between January 2007 and December 2015. We compared overall survival (OS) and recurrence-free survival (RFS) for the 2 groups using the Kaplan-Meier method, and we determined independent risk factors for death and recurrence using multivariate regression analyses. RESULTS: A total of 488 patients with HCC at BCLC B (265 patients with LR, 223 patients with TACE+LR) enrolled from our center. Mean follow-up was 40.2 (range, 3.0-128.7) months. For patients receiving TACE+LR and LR, estimated 1-, 3-, and 5-year OS rates were 90.6% and 73.3%, 61.7% and 43.5%, and 52.9% and 33.8%, respectively (all P < 0.001) and estimated 1-, 2-, and 3-year RFS rates were 54.6% and 39.4%, 41.4% and 29.4%, and 36.3% and 26.3%, respectively (P < 0.001, P = 0.002, and P = 0.008, respectively). Significant independent predictors of poor OS were more than 3 (vs. 3 or fewer) tumors (HR=2.19, 95% CI 1.69-2.84), non-anatomical (vs. anatomical) hepatectomy (HR=1.29, 95% CI 1.01-1.66), microscopic vascular invasion (HR=1.46, 95% CI 1.15-.90), cirrhosis (HR=2.41, 95%CI 1.88-3.01), and intraoperative blood transfusion (HR=1.29, 95% CI 1.01-1.66). CONCLUSION: Preoperative TACE with LR may result in better oncological outcomes than either TACE or LR alone, without a substantial increase in morbidity, and could be considered an effective combination treatment for intermediate-stage HCC.

13.
Front Microbiol ; 11: 2095, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33013765

RESUMO

Biological diversity plays an important role in the stability of ecosystems. The Mu Us Desert (MUD), located in Northern China, is an aeolian desert. Although it has been governed by a series of ecological restoration programs, the MUD still has limited biological diversity. Populus euphratica (P. euphratica), a xerophytic plant, has great potential to improve the biological diversity of the MUD. However, the survival rate of P. euphratica in the MUD has been very low. The current study tried to explore the mechanism of the high death rate of P. euphratica in the microbiome perspective. The correlation study between soil community composition and soil properties showed that water-filled pore space (WFPS), pH, EC, AP, NO3 -, and NH4 + possess higher potential to change the bacterial community (18%) than the fungal community (9%). Principal coordinate analysis indicated that the composition of both bacteria (Proteobacteria and Bacteroidetes) and fungi (Ascomycota) in the root soil can be increased by P. euphratica. By systematically comparing between the fungal diversity in the root soil around P. euphratica and the pathogenic fungus extract from the pathogenic site of P. euphratica, we found that the high death rate of P. euphratica was associated with specific pathogenic fungus Alternaria alternate and Didymella glomerata. In addition, the microbiome composition analysis indicated that P. euphratica planting could also influence the portions of bacteria community, which also has great potential to lead to future infection. However, as the extraction and separation of bacteria from plants is challenging, the correlation between pathogenic bacteria and the high death rate of P. euphratica was not studied here and could be explored in future work.

14.
Appl Radiat Isot ; 166: 109342, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758708

RESUMO

In this paper, standardization of the activity concentration of gaseous beta-emitting radionuclide 85Kr is introduced. The measurement was performed at the recent-established primary standard at the National Institute of Metrology of China (NIM), which consists of a set of internal gas proportional counters of different length. Samples suitable for High Purity Germanium gamma-ray spectrometry measurement were also prepared, and efficiency calibration at an energy of Eγ = 514 keV with standardized 85Kr source in a given geometrical container is presented.

15.
Radiat Prot Dosimetry ; 188(3): 316-321, 2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31957797

RESUMO

Radioactivity of 226Ra, 232Th, and 40K were measured in a total of 92 samples, including eight commonly used types of building materials that were obtained from local manufacturers and suppliers in Beijing. Concentrations were determined using high-purity germanium gamma-ray spectrometry. The 226Ra, 232Th, and 40K activity concentrations in all samples varied from 10.1 to 661, 3.3 to 555 and 3.2 to 2945 Bq per kg with an average of 127.8, 114.8, and 701.5 Bq per kg, respectively. The potential radiological hazards were estimated by calculating the absorbed dose rate (D), radium equivalent activity (Raeq), external hazard (Hex), and internal hazard (Hin) indices. The investigated building materials were classified into different types according to the radioactivity levels. Results from this research will provide a reference for the acquisition, sales, and use of building materials. Attention should be paid to the use of coal cinder brick, ceramic, and granite in the construction of dwellings.


Assuntos
Monitoramento de Radiação , Radioatividade , Rádio (Elemento) , Materiais de Construção , Radioisótopos de Potássio/análise , Doses de Radiação , Rádio (Elemento)/análise , Tório/análise
17.
J Environ Radioact ; 203: 107-111, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30889513

RESUMO

210Pb in food, diet and environmental samples collected in China during the period of 2015-2017 was analyzed and discussed in this study. The activity concentrations of 210Pb were measured by gamma spectrometry, the average of which in sea food, cereal, mushroom, duplicate diet, soil, sediment, biomass ash and aerosol samples were 1.22 ±â€¯0.69 Bq kg-1 fresh weight, 2.77 ±â€¯0.33 Bq kg-1 fresh weight, 8.2 Bq kg-1 dry weight, 1.21 Bq kg-1 dry weight, 172 ±â€¯44 Bq kg-1 dry weight, 87.2 ±â€¯39.2 Bq kg-1 dry weight, 140 ±â€¯185 Bq kg-1 and 813 ±â€¯520 µBq m-3, respectively. The results were higher than those observed in various countries except for seafood. The annual effective dose due to mushroom, duplicate diet and aerosol were estimated. Furthermore, the transfer factor (TF) of 210Pb from soil to some species of mushroom were also considered. This study provided useful data for radiation protection of the public.


Assuntos
Radioisótopos de Chumbo/análise , Exposição à Radiação/estatística & dados numéricos , Monitoramento de Radiação , Poluentes Radioativos da Água/análise , Exposição Dietética , Chumbo/análise , Doses de Radiação
18.
Clin Infect Dis ; 67(11): 1670-1676, 2018 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-29846536

RESUMO

Background: Mass drug administration (MDA), with or without low-dose primaquine (PMQLD), is being considered for malaria elimination programs. The potential of PMQLD to block malaria transmission by mosquitoes must be balanced against liabilities of its use. Methods: Artemisinin-piperaquine (AP), with or without PMQLD, was administered in 3 monthly rounds across Anjouan Island, Union of Comoros. Plasmodium falciparum malaria rates, mortality, parasitemias, adverse events, and PfK13 Kelch-propeller gene polymorphisms were evaluated. Results: Coverage of 85 to 93% of the Anjouan population was achieved with AP plus PMQLD (AP+PMQLD) in 2 districts (population 97164) and with AP alone in 5 districts (224471). Between the months of April-September in both 2012 and 2013, average monthly malaria hospital rates per 100000 people fell from 310.8 to 2.06 in the AP+PMQLD population (ratio 2.06/310.8 = 0.66%; 95% CI: 0.02%, 3.62%; P = .00007) and from 412.1 to 2.60 in the AP population (ratio 0.63%; 95% CI: 0.11%, 1.93%; P < .00001). Effectiveness of AP+PMQLD was 0.9908 (95% CI: 0.9053, 0.9991), while effectiveness of AP alone was 0.9913 (95% CI: 0.9657, 0.9978). Both regimens were well tolerated, without severe adverse events. Analysis of 52 malaria samples after MDA showed no evidence for selection of PfK13 Kelch-propeller mutations. Conclusions: Steep reductions of malaria cases were achieved by 3 monthly rounds of either AP+PMQLD or AP alone, suggesting potential for highly successful MDA without PMQLD in epidemiological settings such as those on Anjouan. A major challenge is to sustain and expand the public health benefits of malaria reductions by MDA.


Assuntos
Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Malária Falciparum/prevenção & controle , Primaquina/uso terapêutico , Quinolinas/uso terapêutico , Adolescente , Adulto , Criança , Pré-Escolar , Comores/epidemiologia , DNA de Protozoário/genética , Quimioterapia Combinada , Doenças Endêmicas/prevenção & controle , Feminino , Humanos , Lactente , Malária Falciparum/epidemiologia , Malária Falciparum/mortalidade , Masculino , Administração Massiva de Medicamentos , Parasitemia/tratamento farmacológico , Parasitemia/epidemiologia , Plasmodium falciparum , Polimorfismo Genético , Resultado do Tratamento , Adulto Jovem
19.
Malar J ; 17(1): 83, 2018 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-29458365

RESUMO

BACKGROUND: Malaria is still one of the serious public health problems in Grande Comore Island, although the number of annual cases has been greatly reduced in recent years. A better understanding of malaria parasite population diversity and transmission dynamics is critical for assessing the effectiveness of malaria control measures. The objective of this study is to investigate temporal changes in genetic diversity of Plasmodium falciparum populations and multiplicity of infection (MOI) in Grande Comore 10 years after introduction of ACT. METHODS: A total of 232 P. falciparum clinical isolates were collected from the Grande Comore Island during two sampling periods (118 for 2006‒2007 group, and 114 for 2013‒2016 group). Parasite isolates were characterized for genetic diversity and complexity of infection by genotyping polymorphic regions in merozoite surface protein gene 1 (msp-1), msp-2, and msp-3 using nested PCR and DNA sequencing. RESULTS: Three msp-1 alleles (K1, MAD20, and RO33), two msp-2 alleles (FC27 and 3D7), and two msp-3 alleles (K1 and 3D7) were detected in parasites of both sampling periods. The RO33 allele of msp-1 (84.8%), 3D7 allele of msp-2 (90.8%), and K1 allele of msp-3 (66.7%) were the predominant allelic types in isolates from 2006-2007 group. In contrast, the RO33 allele of msp-1 (63.4%), FC27 allele of msp-2 (91.1%), and 3D7 allele of msp-3 (53.5%) were the most prevalent among isolates from the 2013-2016 group. Compared with the 2006‒2007 group, polyclonal infection rates of msp-1 (from 76.7 to 29.1%, P < 0.01) and msp-2 (from 62.4 to 28.3%, P < 0.01) allelic types were significantly decreased in those from 2013‒2016 group. Similarly, the MOIs for both msp-1 and msp-2 were higher in P. falciparum isolates in the 2006-2007 group than those in 2013-2016 group (MOI = 3.11 vs 1.63 for msp-1; MOI = 2.75 vs 1.35 for msp-2). DNA sequencing analyses also revealed reduced numbers of distinct sequence variants in the three genes from 2006‒2007 to 2013‒2016: msp-1, from 32 to 23 (about 28% decline); msp-2 from 29 to 21 (about 28% decline), and msp-3 from 11 to 3 (about 72% decline). CONCLUSIONS: The present data showed dramatic reduction in genetic diversity and MOI among Grande Comore P. falciparum populations over the course of the study, suggesting a trend of decreasing malaria transmission intensity and genetic diversity in Grande Comore Island. These data provide valuable information for surveillance of P. falciparum infection and for assessing the appropriateness of the current malarial control strategies in the endemic area.


Assuntos
Antígenos de Protozoários/genética , Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Quimioterapia Combinada/estatística & dados numéricos , Variação Genética , Proteína 1 de Superfície de Merozoito/genética , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Comores , Humanos
20.
Magn Reson Imaging ; 47: 60-66, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29103978

RESUMO

OBJECTIVE: To explore the diffusion and kurtosis features of cervical cancer (CC) and study the feasibility of diffusion kurtosis imaging (DKI) based on the non-Gaussian diffusion-weighted model to differentiate the stage and grade of CC. METHODS: A total of 50 patients with pathologically confirmed CC were enrolled. MRI examinations including DKI (with 5b values 200, 500, 1000, 1500, and 2000smm-2 were performed before any treatment. The apparent coefficient (Dapp) and the apparent kurtosis value (Kapp) were derived from the non-gaussian diffusion model, and the apparent diffusion coefficient (ADC) was derived from the Gaussian model. The parameters of CC and normal tissue (myometrium) were obtained, analyzed statistically, and evaluated with respect to differentiating stage and grade between the tissue and the CC. RESULTS: ADC and Dapp values of CC were significantly lower than that of the normal myometrium (P=0.024 and P<0.001, respectively), while the Kapp value was not found to exhibit a significant difference. Compared to the well/moderately differentiated CC, poorly differentiated CC had a significantly decreased mean ADC and Dapp (P=0.018 and P=0.026, respectively); however, the mean Kapp (P=0.035) increased significantly. In the clinical staging, the DKI sequence was advantageous over conventional MRI sequences (degree of accuracy: 90% vs. 74%), Although in the quantitative analysis, these parameters did not show a significant difference. CONCLUSIONS: The pilot study demonstrated that these diffusion and kurtosis indices from DKI based on the non-Gaussian diffusion-weighted model putatively differentiated the grade and stage of CC.


Assuntos
Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Neoplasias do Colo do Útero/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Miométrio/diagnóstico por imagem , Distribuição Normal , Projetos Piloto , Reprodutibilidade dos Testes , Estudos Retrospectivos
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