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1.
Cell Host Microbe ; 31(12): 2093-2106.e7, 2023 Dec 13.
Article in English | MEDLINE | ID: mdl-38056457

ABSTRACT

The erythrocyte silent Duffy blood group phenotype in Africans is thought to confer resistance to Plasmodium vivax blood-stage infection. However, recent studies report P. vivax infections across Africa in Fy-negative individuals. This suggests that the globin transcription factor 1 (GATA-1) SNP underlying Fy negativity does not entirely abolish Fy expression or that P. vivax has developed a Fy-independent red blood cell (RBC) invasion pathway. We show that RBCs and erythroid progenitors from in vitro differentiated CD34 cells and from bone marrow aspirates from Fy-negative samples express a functional Fy on their surface. This suggests that the GATA-1 SNP does not entirely abolish Fy expression. Given these results, we developed an in vitro culture system for P. vivax and show P. vivax can invade erythrocytes from Duffy-negative individuals. This study provides evidence that Fy is expressed in Fy-negative individuals and explains their susceptibility to P. vivax with major implications and challenges for P. vivax malaria eradication.


Subject(s)
Malaria, Vivax , Plasmodium vivax , Humans , Plasmodium vivax/metabolism , Antigens, Protozoan , Erythropoiesis , Erythrocytes , Duffy Blood-Group System/genetics , Duffy Blood-Group System/metabolism
2.
Pharmacogenomics ; 24(11): 583-597, 2023 07.
Article in English | MEDLINE | ID: mdl-37551613

ABSTRACT

Aim: Antimalarial primaquine (PQ) eliminates liver hypnozoites of Plasmodium vivax. CYP2D6 gene variation contributes to PQ therapeutic failure. Additional gene variation may contribute to PQ efficacy. Information on pharmacogenomic variation in Madagascar, with vivax malaria and a unique population admixture, is scanty. Methods: The authors performed genome-wide genotyping of 55 Malagasy samples and analyzed data with a focus on a set of 28 pharmacogenes most relevant to PQ. Results: Mainly, the study identified 110 coding or splicing variants, including those that, based on previous studies in other populations, may be implicated in PQ response and copy number variation, specifically in chromosomal regions that contain pharmacogenes. Conclusion: With this pilot information, larger genome-wide association analyses with PQ metabolism and response are substantially more feasible.


Subject(s)
Antimalarials , Humans , Antimalarials/therapeutic use , Primaquine/therapeutic use , DNA Copy Number Variations/genetics , Genome-Wide Association Study , Pharmacogenetics , Chloroquine/therapeutic use
3.
Pharmacogenomics ; 23(5): 315-325, 2022 04.
Article in English | MEDLINE | ID: mdl-35230160

ABSTRACT

Background:Plasmodium vivax malaria is endemic in Madagascar, where populations have genetic inheritance from Southeast Asia and East Africa. Primaquine, a drug of choice for vivax malaria, is metabolized principally via CYP2D6. CYP2D6 variation was characterized by locus-specific gene sequencing and was compared with TaqMan™ genotype data. Materials & methods: Long-range PCR amplicons were generated from 96 Malagasy samples and subjected to next-generation sequencing. Results: The authors observed high concordance between TaqMan™-based CYP2D6 genotype calls and the base calls from sequencing. In addition, there are new variants and haplotypes present in the Malagasy. Conclusion: Sequencing unique admixed populations provides more detailed and accurate insights regarding CYP2D6 variability, which may help optimize primaquine treatment across human genetic diversity.


Subject(s)
Antimalarials , Cytochrome P-450 CYP2D6 , Africa , Antimalarials/therapeutic use , Asia , Cytochrome P-450 CYP2D6/genetics , Cytochrome P-450 CYP2D6/metabolism , Humans , Pilot Projects , Primaquine/therapeutic use
4.
Front Pharmacol ; 12: 654054, 2021.
Article in English | MEDLINE | ID: mdl-33959023

ABSTRACT

Plasmodium vivax is one of the five human malaria parasite species, which has a wide geographical distribution and can cause severe disease and fatal outcomes. It has the ability to relapse from dormant liver stages (hypnozoites), weeks to months after clearance of the acute blood-stage infection. An 8-aminoquinoline drug primaquine (PQ) can clear the hypnozoites, and thus can be used as an anti-relapse therapeutic agent. Recently, a number of studies have found that its efficacy is compromised by polymorphisms in the cytochrome P450 2D6 (CYP2D6) gene; decreased or absence of CYP2D6 activity contributes to PQ therapeutic failure. The present study sought to characterize CYP2D6 genetic variation in Madagascar, where populations originated from admixture between Asian and African populations, vivax malaria is endemic, and PQ can be deployed soon to achieve national malaria elimination. In a total of 211 samples collected from two health districts, CYP2D6 decreased function alleles CYP2D6*10, *17, *29, *36+*10, and *41 were observed at frequencies of 3.55-17.06%. In addition, nonfunctional alleles were observed, the most common of which were CYP2D6*4 (2.13%), *5 (1.66%), and the *4x2 gene duplication (1.42%). Given these frequencies, 34.6% of the individuals were predicted to be intermediate metabolizers (IM) with an enzyme activity score (AS) ≤ 1.0; both the IM phenotype and AS ≤ 1.0 have been found to be associated with PQ therapeutic failure. Furthermore, the allele and genotype frequency distributions add to the archaeological and genomic evidence of Malagasy populations constituting a unique, Asian-African admixed origin. The results from this exploratory study provide fresh insights about genomic characteristics that could affect the metabolism of PQ into its active state, and may enable optimization of PQ treatment across human genetic diversity, which is critical for achieving P. vivax elimination.

5.
Public Health ; 190: 93-98, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33385640

ABSTRACT

OBJECTIVES: The objective of the study is the identification of racial differences in characteristics and comorbidities in patients hospitalized for COVID-19 and the impact on outcomes. STUDY DESIGN: The study design is a retrospective observational study. METHODS: Data for all patients admitted to seven community hospitals in Michigan, United States, with polymerase chain reaction confirmed diagnosis of COVID-19 from March 10 to April 15, 2020 were analyzed. The primary outcomes of racial disparity in inpatient mortality and intubation were analyzed using descriptive statistics and multivariate regression models. RESULTS: The study included 336 Black and 408 White patients. Black patients were younger (62.9 ± 15.0 years vs 71.8 ± 16.4, P < .001), had a higher mean body mass index (32.4 ± 8.6 kg/m2 vs 28.8 ± 7.5, P < .001), had higher prevalence of diabetes (136/336 vs 130/408, P = .02), and presented later (6.6 ± 5.3 days after symptom onset vs. 5.4 ± 5.4, P = .006) compared with White patients. Younger Black patients had a higher prevalence of obesity (age <65 years, 69.9%) than older Black patients (age >65 years, 39.2%) and younger White patients (age < 65, 55.1%). Intubation did not reach statistical significance for racial difference (Black patients 61/335 vs. 54/406, P = .08). Mortality was not higher in Black patients (65/335 vs. 142/406 in White patients, odds ratio 0.61, 95% confidence interval: 0.37 to 0.99, 2-sided P = .05) in multivariate analysis, accounting for other risk factors associated with mortality. CONCLUSIONS: Higher prevalence of obesity and diabetes in young Black populations may be the critical factor driving disproportionate COVID-19 hospitalizations in Black populations. Hospitalized Black patients do not have worse outcomes compared with White patients.


Subject(s)
COVID-19/ethnology , COVID-19/therapy , Diabetes Mellitus/epidemiology , Hospitalization/statistics & numerical data , Obesity/epidemiology , Racial Groups/statistics & numerical data , SARS-CoV-2 , Black or African American/statistics & numerical data , Aged , Body Mass Index , COVID-19/mortality , COVID-19/virology , Comorbidity , Female , Health Status Disparities , Healthcare Disparities/ethnology , Healthcare Disparities/statistics & numerical data , Hospitals, Community , Humans , Intensive Care Units , Male , Michigan/epidemiology , Middle Aged , Pandemics , Prevalence , Pulmonary Disease, Chronic Obstructive/epidemiology , Racial Groups/ethnology , Retrospective Studies , Risk Factors , White People/statistics & numerical data
6.
Sci Rep ; 10(1): 18129, 2020 10 22.
Article in English | MEDLINE | ID: mdl-33093622

ABSTRACT

Malaria transmission in Madagascar is highly heterogeneous, exhibiting spatial, seasonal and long-term trends. Previous efforts to map malaria risk in Madagascar used prevalence data from Malaria Indicator Surveys. These cross-sectional surveys, conducted during the high transmission season most recently in 2013 and 2016, provide nationally representative prevalence data but cover relatively short time frames. Conversely, monthly case data are collected at health facilities but suffer from biases, including incomplete reporting and low rates of treatment seeking. We combined survey and case data to make monthly maps of prevalence between 2013 and 2016. Health facility catchment populations were estimated to produce incidence rates from the case data. Smoothed incidence surfaces, environmental and socioeconomic covariates, and survey data informed a Bayesian prevalence model, in which a flexible incidence-to-prevalence relationship was learned. Modelled spatial trends were consistent over time, with highest prevalence in the coastal regions and low prevalence in the highlands and desert south. Prevalence was lowest in 2014 and peaked in 2015 and seasonality was widely observed, including in some lower transmission regions. These trends highlight the utility of monthly prevalence estimates over the four year period. By combining survey and case data using this two-step modelling approach, we were able to take advantage of the relative strengths of each metric while accounting for potential bias in the case data. Similar modelling approaches combining large datasets of different malaria metrics may be applicable across sub-Saharan Africa.


Subject(s)
Malaria, Falciparum/diagnosis , Malaria, Falciparum/epidemiology , Plasmodium falciparum/isolation & purification , Population Surveillance , Spatio-Temporal Analysis , Bayes Theorem , Cross-Sectional Studies , Health Surveys , Humans , Madagascar/epidemiology , Malaria, Falciparum/parasitology , Prevalence
7.
PLoS Negl Trop Dis ; 13(7): e0007176, 2019 07.
Article in English | MEDLINE | ID: mdl-31276491

ABSTRACT

BACKGROUND: The Madagascar National Strategic Plan for Malaria Control 2018 (NSP) outlines malaria control pre-elimination strategies that include detailed goals for mosquito control. Primary surveillance protocols and mosquito control interventions focus on indoor vectors of malaria, while many potential vectors feed and rest outdoors. Here we describe the application of tools that advance our understanding of diversity, host choice, and Plasmodium infection in the Anopheline mosquitoes of the Western Highland Fringe of Madagascar. METHODOLOGY/PRINCIPAL FINDINGS: We employed a modified barrier screen trap, the QUadrant Enabled Screen Trap (QUEST), in conjunction with the recently developed multiplex BLOOdmeal Detection Assay for Regional Transmission (BLOODART). We captured a total of 1252 female Anopheles mosquitoes (10 species), all of which were subjected to BLOODART analysis. QUEST collection captured a heterogenous distribution of mosquito density, diversity, host choice, and Plasmodium infection. Concordance between Anopheles morphology and BLOODART species identifications ranged from 93-99%. Mosquito feeding behavior in this collection frequently exhibited multiple blood meal hosts (single host = 53.6%, two hosts = 42.1%, three hosts = 4.3%). The overall percentage of human positive bloodmeals increased between the December 2017 and the April 2018 timepoints (27% to 44%). Plasmodium positivity was frequently observed in the abdomens of vectors considered to be of secondary importance, with an overall prevalence of 6%. CONCLUSIONS/SIGNIFICANCE: The QUEST was an efficient tool for sampling exophilic Anopheline mosquitoes. Vectors considered to be of secondary importance were commonly found with Plasmodium DNA in their abdomens, indicating a need to account for these species in routine surveillance efforts. Mosquitoes exhibited multiple blood feeding behavior within a gonotrophic cycle, with predominantly non-human hosts in the bloodmeal. Taken together, this complex feeding behavior could enhance the role of multiple Anopheline species in malaria transmission, possibly tempered by zoophilic feeding tendencies.


Subject(s)
Anopheles/physiology , Anopheles/parasitology , Feeding Behavior , Malaria/prevention & control , Mosquito Control/methods , Animals , Blood , Disease Vectors , Epidemiological Monitoring , Female , Host-Parasite Interactions , Humans , Madagascar , Malaria/transmission , Plasmodium/physiology
8.
Am J Trop Med Hyg ; 100(5): 1196-1201, 2019 05.
Article in English | MEDLINE | ID: mdl-30834883

ABSTRACT

Current malaria rapid diagnostic tests (RDTs) contain antibodies against Plasmodium falciparum-specific histidine-rich protein 2 (PfHRP2), Plasmodium lactate dehydrogenase (pLDH), and aldolase in various combinations. Low or high parasite densities/target antigen concentrations may influence the accuracy and sensitivity of PfHRP2-detecting RDTs. We analyzed the SD Bioline Malaria Ag P.f/Pan RDT performance in relation to P. falciparum parasitemia in Madagascar, where clinical Plasmodium vivax malaria exists alongside P. falciparum. Nine hundred sixty-three samples from patients seeking care for suspected malaria infection were analyzed by RDT, microscopy, and Plasmodium species-specific, ligase detection reaction-fluorescent microsphere assay (LDR-FMA). Plasmodium infection positivity by these diagnostics was 47.9%, 46.9%, and 58%, respectively. Plasmodium falciparum-only infections were predominant (microscopy, 45.7%; LDR-FMA, 52.3%). In all, 16.3% of P. falciparum, 70% of P. vivax, and all of Plasmodium malariae, Plasmodium ovale, and mixed-species infections were submicroscopic. In 423 P. falciparum mono-infections, confirmed by microscopy and LDR-FMA, the parasitemia in those who were positive for both the PfHRP2 and pan-pLDH test bands was significantly higher than that in those who were positive only for the PfHRP2 band (P < 0.0001). Plasmodium falciparum parasitemia in those that were detected as P. falciparum-only infections by microscopy but P. falciparum mixed infections by LDR-FMA also showed similar outcome by the RDT band positivity. In addition, we used varying parasitemia (3-0.0001%) of the laboratory-maintained 3D7 strain to validate this observation. A positive pLDH band in high P. falciparum-parasitemic individuals may complicate diagnosis and treatment, particularly when the microscopy is inconclusive for P. vivax, and the two infections require different treatments.


Subject(s)
Antigens, Protozoan/analysis , Diagnostic Tests, Routine/standards , L-Lactate Dehydrogenase/analysis , Malaria, Falciparum/diagnosis , Malaria, Vivax/diagnosis , Parasitemia/diagnosis , Protozoan Proteins/analysis , Antigens, Protozoan/immunology , Fructose-Bisphosphate Aldolase/analysis , Fructose-Bisphosphate Aldolase/immunology , Humans , L-Lactate Dehydrogenase/immunology , Madagascar , Microscopy , Plasmodium falciparum/enzymology , Plasmodium vivax , Protozoan Proteins/immunology , Sensitivity and Specificity
9.
Am J Trop Med Hyg ; 100(3): 544-551, 2019 03.
Article in English | MEDLINE | ID: mdl-30675844

ABSTRACT

Anopheles mosquitoes vary in habitat preference, feeding pattern, and susceptibility to various measures of vector control. Consequently, it is important that we identify reservoirs of disease, identify vectors, and characterize feeding patterns to effectively implement targeted control measures. Using 467 anopheline mosquito abdomen squashes captured in Madagascar, we designed a novel ligase detection reaction and fluorescent microsphere assay, dubbed Bloodmeal Detection Assay for Regional Transmission (BLOODART), to query the bloodmeal content, identify five Anopheles mosquito species, and detect Plasmodium infection. Validation of mammalian bloodspots was achieved by preparation and analysis of known hosts (singular and mixed), sensitivity to degradation and storage method were assessed through mosquito feeding experiments, and quantification was explored by altering ratios of two mammal hosts. BLOODART identifications were validated by comparison with mosquito samples identified by sequenced portions of the internal transcribed spacer 2. BLOODART identification of control mammal bloodspots was 100% concordant for singular and mixed mammalian blood. BLOODART was able to detect hosts up to 42 hours after digestion when mosquito samples were stored in ethanol. A mammalian host was identified in every field-collected, blood-fed female Anopheles mosquito by BLOODART. The predominant mosquito host was cow (n = 451), followed by pig (n = 26) and human (n = 25). Mixed species bloodmeals were commonly observed (n = 33). A BLOODART molecular identification was successful for 318/467 mosquitoes, with an overall concordance of 60% with all field-captured, morphologically identified Anopheles specimens. BLOODART enables characterization of large samples and simultaneous pathogen detection to monitor and incriminate disease vectors in Madagascar.


Subject(s)
Anopheles/parasitology , Feeding Behavior , Mammals/blood , Plasmodium/isolation & purification , Animals , Anopheles/genetics , Fluorescent Antibody Technique , Host Specificity , Humans , Madagascar , Species Specificity
10.
Am J Trop Med Hyg ; 98(6): 1683-1691, 2018 06.
Article in English | MEDLINE | ID: mdl-29557337

ABSTRACT

Plasmodium falciparum histidine-rich protein 2 (PfHRP2) forms the basis of many current malaria rapid diagnostic tests (RDTs). However, the parasites lacking part or all of the pfhrp2 gene do not express the PfHRP2 protein and are, therefore, not identifiable by PfHRP2-detecting RDTs. We evaluated the performance of the SD Bioline Malaria Ag P.f/Pan RDT together with pfhrp2 variation in Madagascar. Genomic DNA isolated from 260 patient blood samples were polymerase chain reaction (PCR)-amplified for the parasite 18S rRNA and pfhrp2 genes. Post-PCR ligation detection reaction-fluorescent microsphere assay (LDR-FMA) was performed for the identification of parasite species. Plasmodium falciparum histidine-rich protein 2 amplicons were sequenced. Polymerase chain reaction diagnosis of patient samples showed that 29% (75/260) were infected and P. falciparum was present in 95% (71/75) of these PCR-positive samples. Comparing RDT and P. falciparum detection by LDR-FMA, eight samples were RDT negative but P. falciparum positive (false negatives), all of which were pfhrp2 positive. The sensitivity and specificity of the RDT were 87% and 90%, respectively. Seventy-three samples were amplified for pfhrp2, from which nine randomly selected amplicons were sequenced, yielding 13 sequences. Amplification of pfhrp2, combined with RDT analysis and P. falciparum detection by LDR-FMA, showed that there was no indication of pfhrp2 deletion. Sequence analysis of pfhrp2 showed that the correlation between pfhrp2 sequence structure and RDT detection rates was unclear. Although the observed absence of pfhrp2 deletion from the samples screened here is encouraging, continued monitoring of the efficacy of the SD Bioline Malaria Ag P.f/Pan RDT for malaria diagnosis in Madagascar is warranted.


Subject(s)
Antigens, Protozoan/genetics , Malaria, Falciparum/diagnosis , Plasmodium falciparum/isolation & purification , Protozoan Proteins/genetics , DNA, Protozoan/blood , DNA, Ribosomal/blood , Diagnostic Tests, Routine , Humans , Madagascar , Malaria, Falciparum/parasitology , Plasmodium falciparum/genetics , Polymerase Chain Reaction , Sensitivity and Specificity
11.
Malar J ; 16(1): 442, 2017 11 03.
Article in English | MEDLINE | ID: mdl-29100506

ABSTRACT

BACKGROUND: Plasmodium vivax is the most prevalent human malaria parasite and is likely to increase proportionally as malaria control efforts more rapidly impact the prevalence of Plasmodium falciparum. Despite the prominence of P. vivax as a major human pathogen, vivax malaria qualifies as a neglected and under-studied tropical disease. Significant challenges bringing P. vivax into the laboratory, particularly the capacity for long-term propagation of well-characterized strains, have limited the study of this parasite's red blood cell (RBC) invasion mechanism, blood-stage development, gene expression, and genetic manipulation. METHODS AND RESULTS: Patient isolates of P. vivax have been collected and cryopreserved in the rural community of Ampasimpotsy, located in the Tsiroanomandidy Health District of Madagascar. Periodic, monthly overland transport of these cryopreserved isolates to the country's National Malaria Control Programme laboratory in Antananarivo preceded onward sample transfer to laboratories at Case Western Reserve University, USA. There, the P. vivax isolates have been cultured through propagation in the RBCs of Saimiri boliviensis. For the four patient isolates studied to-date, the median time interval between sample collection and in vitro culture has been 454 days (range 166-961 days). The median time in culture, continually documented by light microscopy, has been 159 days; isolate AMP2014.01 was continuously propagated for 233 days. Further studies show that the P. vivax parasites propagated in Saimiri RBCs retain their ability to invade human RBCs, and can be cryopreserved, thawed and successfully returned to productive in vitro culture. CONCLUSIONS/SIGNIFICANCE: Long-term culture of P. vivax is possible in the RBCs of Saimiri boliviensis. These studies provide an alternative to propagation of P. vivax in live animals that are becoming more restricted. In vitro culture of P. vivax in Saimiri RBCs provides an opening to stabilize patient isolates, which would serve as precious resources to apply new strategies for investigating the molecular and cellular biology of this important malaria parasite.


Subject(s)
Cell Culture Techniques/methods , Plasmodium vivax/physiology , Saimiri/parasitology , Animals , Cryopreservation , Erythrocytes/parasitology , Humans , Madagascar , Saimiri/blood , Specimen Handling
12.
Gene ; 575(2 Pt 1): 353-8, 2016 Jan 10.
Article in English | MEDLINE | ID: mdl-26335514

ABSTRACT

Prader-Willi and Angelman syndromes are two distinct neurogenetic disorders caused by chromosomal deletions, uniparental disomy or loss of the imprinted gene expression in the 15q11-q13 region. PWS results from the lack of the paternally expressed gene contribution in the region. The aim of our study was to compare a new molecular approach based on the quantification of the expression of non-imprinted bi-allelic gene (NIPA1 and OCA2) with in house MS-PCR and the MS-MLPA test. Blood samples were collected from 12 patients, clinical criteria positives for Prader-Willi syndrome. DNA and RNA samples were isolated from white blood cells. Epigenetic changes at SNRPN gene locus were evaluated by MS-PCR technique. The expression levels of two non-imprinted genes (NIPA1 and OCA2) were evaluated in qReal-Time PCR, in order to identify type 1 and type 2 deletions. SALSA MS-MLPA kit ME028 was used to detect copy number changes and to analyze CpG islands methylation of the 15q11 region. MS-MLPA test confirmed that 8/12 patients presented different types of deletion at the SNRPN gene level (promoter, introns, and exons) and 4/8 displayed type 1 or type 2 deletion. In children with 15q11-13 deletions, the decreased level of NIPA1and OCA2 gene expression is related to chromosomal abnormality in the investigated area. The deletions were confirmed by MS-MLPA analysis, thus recommending NIPA1 and OCA2 gene expression as an alternate method to investigate deletions.


Subject(s)
Chromosomes, Human, Pair 15 , Gene Expression Regulation , Membrane Proteins , Membrane Transport Proteins , Prader-Willi Syndrome , Sequence Deletion , Child , Child, Preschool , Chromosome Aberrations , Chromosomes, Human, Pair 15/genetics , Chromosomes, Human, Pair 15/metabolism , CpG Islands , DNA Methylation , Female , Genetic Loci , Humans , Infant , Male , Membrane Proteins/biosynthesis , Membrane Proteins/genetics , Membrane Transport Proteins/biosynthesis , Membrane Transport Proteins/genetics , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Prader-Willi Syndrome/metabolism , Real-Time Polymerase Chain Reaction
13.
Eur J Endocrinol ; 171(3): 389-97, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24966174

ABSTRACT

CONTEXT: Cutoff limits of GH stimulation tests to diagnose GH deficiency (GHD) in children and adolescents are not sufficiently validated by clinical studies due to discrepancies in the performance of GH immunoassays and lack of available study populations. OBJECTIVE: We aimed to establish new cutoff limits for GH stimulation tests based on clinical evidence and compared these immunoassay-based values with an antibody-independent mass spectrometric method. DESIGN AND SETTING: In a retrospective study, GH cutoff limits for eight different immunoassays and isotope dilution mass spectrometry (ID-MS) were calculated from hGH peak concentrations of short-statured children with and without GHD. PATIENTS: We compared the serum GH peak concentrations at GH stimulation test of 52 short-statured children and adolescents, who have normal GH secretion at initial workup and normal growth in the follow-up, with the serum GH peak concentrations of 44 GHD patients in the same age range, in order to optimize the cutoff limit calculation. RESULTS: Discriminant analysis of re-measured GH led to a new cutoff limit of 7.09 µg/l using the iSYS assay (IDS) and the limits for the other seven hGH assays varied between 4.32 and 7.77 µg/l. For ID-MS, cutoffs of 5.48 µg/l (22k GH) and 7.43 µg/l (total GH) were ascertained. CONCLUSION: The establishment of method-specific clinical evidence-based GH cutoff limits is of importance to ensure adequate clinical diagnosis and treatment of children and adolescents with GHD. ID-MS may become an important tool for providing both reliable and sustainable SI traceability of GH measurements in the future.


Subject(s)
Growth Disorders/diagnosis , Human Growth Hormone/biosynthesis , Mass Spectrometry/standards , Body Height/physiology , Child , Child, Preschool , Databases, Factual/standards , Female , Growth Disorders/blood , Human Growth Hormone/blood , Humans , Male , Retrospective Studies
14.
Environ Sci Technol ; 47(14): 7729-38, 2013 Jul 16.
Article in English | MEDLINE | ID: mdl-23751015

ABSTRACT

Product analyses of the NO3 radical-initiated oxidation of ortho-, meta-, and para-cresol have been performed in large-volume chamber systems at the University of Wuppertal (1080 L quartz glass reactor: QUAREC) and the European Photoreactor (EUPHORE), Valencia, Spain. The reaction of O3 with NO2 was used for the in situ generation of NO3 radicals in both QUAREC and EUPHORE. In the QUAREC experiments the gas-phase reaction of ortho-cresol isomer with NO3 yielded (11.5 ± 0.8) % 6-methyl-2-nitrophenol (6M2NP), (4.4 ± 0.3) % methyl-1,4-benzoquinone (MQUIN) and (77.2 ± 6.3) % HNO3. The reaction of NO3 radicals with meta-cresol yielded (21.2 ± 1.4) % 3-methyl-2-nitrophenol (3M2NP), (22.8 ± 1.8) % 3-methyl-4-nitrophenol (3M4NP), (23.5 ± 1.8) % 5-methyl-2-nitrophenol (5M2NP), (4.2 ± 0.7) % MQUIN and (72.3 ± 6.4) % HNO3. In the reaction of NO3 radicals with para-cresol, 4-methyl-2-nitrophenol (4M2NP) and HNO3 were identified as products with yields of (41.3 ± 3.7) % and (85.0 ± 10.2) %, respectively. In the EUPHORE chamber not all products were formed at levels above the detection limit, however, in cases where detection was possible similar product yields were observed. The product formation yields determined in both chambers are compared with available literature data and a gas-phase mechanism is proposed to explain the formation of the products observed from the reaction of NO3 and with cresol isomers.


Subject(s)
Cresols/chemistry , Nitrates/chemistry , Isomerism , Limit of Detection , Spectroscopy, Fourier Transform Infrared
15.
Med Eng Phys ; 35(8): 1116-32, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23317551

ABSTRACT

The purpose of this paper is to explore both an extended and a reduced set of input parameters of the Finite Element (FE) model of the human lower limb with a Total Knee Replacement (TKR) implant. The most influential parameters in determining the size and the shape of the performance envelopes of eight kinematics and peak contact pressure output variables of the tibio-femoral joint and the patello-femoral joint are sought. The lower limb FE model, which includes bones, TKR implant, soft tissues and applied forces of realistic size, is used in the context of the stair ascent simulation. Two probabilistic methods are used together with the FE model to generate the performance envelopes and to explore the sensitivities of the input parameters of the FE model: the Monte Carlo simulation and the Response Surface Method (RSM). A total of four probabilistic FE analyses assess how the uncertainties in an extended set of 77 input variables and a reduced set of 22 input variables obtained from the RSM/sensitivity analyses affect the performance envelopes. It is shown that the FE model with the reduced set of variables is able to replicate the full FE model. The differences between the Monte Carlo envelopes of performance obtained with the FE model with the full set of variables and the FE model with the reduced set of variables were on average over all output measures under 1.67 mm for translations, 1.75° for rotations and under 2 MPa for peak contact pressures. The differences between the RSM and the Monte Carlo envelopes of performances obtained with the reduced set of input variables were, on average, over all output measures under 0.75 mm for translations, 1.26° for rotations and 2.39 MPa for peak contact pressures. While saving computational time with the reduced set of variables, the findings are especially of high importance to the orthopedic surgeons who would like to know the most important parameters that can influence the performance of the TKR for a given human activity.


Subject(s)
Arthroplasty, Replacement, Knee/methods , Knee Joint/physiopathology , Knee Joint/surgery , Models, Biological , Models, Statistical , Patellofemoral Joint/physiopathology , Patellofemoral Joint/surgery , Computer Simulation , Finite Element Analysis , Friction , Humans , Pressure , Prognosis , Range of Motion, Articular , Surgery, Computer-Assisted/methods , Treatment Outcome , Weight-Bearing
16.
Int J Tuberc Lung Dis ; 15(9): 1239-45, i, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21943852

ABSTRACT

SETTING: Investigation of trace metal behaviour during the treatment of active pulmonary tuberculosis (PTB) patients residing in Romania. OBJECTIVE: To assess, follow and identify serum iron (Fe), copper (Cu) and zinc (Zn) levels in patients diagnosed and treated for active PTB. DESIGN: Chemical and statistical analysis of various biochemical parameters in 47 subjects diagnosed with active PTB and 170 healthy Romanian residents. RESULTS: Copper and ceruloplasmin levels were increased in patients with active PTB compared to the control group (P < 0.01), while the serum Zn level was significantly lower than in healthy subjects (P < 0.01) or within the normal range. The present study shows that there is a significant correlation between serum Cu concentrations and ceruloplasmin. CONCLUSIONS: This study provides preliminary evidence that Zn and Fe redistribution is operating as a primary host defence mechanism to reduce the availability of metals for microbial metabolism during infection. The study also calls attention to the fact that anti-tuberculosis treatment is sufficient to enhance the concentration of the antioxidant species (Cu and ceruloplasmin). The data obtained suggest that serum Cu, Zn and Cu/Zn levels may serve as indirect pointers in the diagnosis of a disease but they cannot be considered as specific markers for TB.


Subject(s)
Antioxidants/metabolism , Ceruloplasmin/metabolism , Trace Elements/blood , Tuberculosis, Pulmonary/blood , Adult , Antitubercular Agents/pharmacology , Antitubercular Agents/therapeutic use , Case-Control Studies , Copper/blood , Female , Follow-Up Studies , Humans , Iron/blood , Male , Middle Aged , Romania , Tuberculosis, Pulmonary/drug therapy , Young Adult , Zinc/blood
17.
Comput Methods Biomech Biomed Engin ; 13(6): 701-9, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20162473

ABSTRACT

Explicit finite element (FE) and multi-body dynamics (MBD) models have been developed to evaluate total knee replacement (TKR) mechanics as a complement to experimental methods. In conjunction with these models, probabilistic methods have been implemented to predict performance bounds and identify important parameters, subject to uncertainty in component alignment and experimental conditions. Probabilistic methods, such as advanced mean value (AMV) and response surface method (RSM), provide an efficient alternative to the gold standard Monte Carlo simulation technique(MCST). The objective of the current study was to benchmark models from three platforms (two FE and one MBD) using various probabilistic methods by predicting the influence of alignment variability and experimental parameters on TKR mechanics in simulated gait. Predicted kinematics envelopes were on average about 2.6mm for tibial anterior-posterior translation, 2.98 for tibial internal­external rotation and 1.9 MPa for tibial peak contact pressure for the various platforms and methods. Based on this good agreement with the MCST, the efficient probabilistic techniques may prove useful in the fast evaluation of new implant designs, including considerations of uncertainty, e.g. misalignment.


Subject(s)
Arthroplasty, Replacement, Knee , Probability , Biomechanical Phenomena , Finite Element Analysis , Humans , Monte Carlo Method , Tibia/physiology , Uncertainty
18.
Health Technol Assess ; 13(16): iii-iv, xi-xiii, 1-113, 137-347, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19272272

ABSTRACT

OBJECTIVES: The two objectives were: (1) to identify, appraise and synthesise research that is relevant to selected UK National Screening Committee (NSC) criteria for a screening programme in relation to partner violence; and (2) to judge whether current evidence fulfils selected NSC criteria for the implementation of screening for partner violence in health-care settings. DATA SOURCES: Fourteen electronic databases from their respective start dates to 31 December 2006. REVIEW METHODS: The review examined seven questions linked to key NSC criteria: QI: What is the prevalence of partner violence against women and what are its health consequences? QII: Are screening tools valid and reliable? QIII: Is screening for partner violence acceptable to women? QIV: Are interventions effective once partner violence is disclosed in a health-care setting? QV: Can mortality or morbidity be reduced following screening? QVI: Is a partner violence screening programme acceptable to health professionals and the public? QVII: Is screening for partner violence cost-effective? Data were selected using different inclusion/exclusion criteria for the seven review questions. The quality of the primary studies was assessed using published appraisal tools. We grouped the findings of the surveys, diagnostic accuracy and intervention studies, and qualitatively analysed differences between outcomes in relation to study quality, setting, populations and, where applicable, the nature of the intervention. We systematically considered each of the selected NSC criteria against the review evidence. RESULTS: The lifetime prevalence of partner violence against women in the general UK population ranged from 13% to 31%, and in clinical populations it was 13-35%. The 1-year prevalence ranged from 4.2% to 6% in the general population. This showed that partner violence against women is a major public health problem and potentially appropriate for screening and intervention. The HITS (Hurts, Insults, Threatens and Screams) scale was the best of several short screening tools for use in health-care settings. Most women patients considered screening acceptable (range 35-99%), although they identified potential harms. The evidence for effectiveness of advocacy is growing, and psychological interventions may be effective, but not necessarily for women identified through screening. No trials of screening programmes measured morbidity and mortality. The acceptability of partner violence screening among health-care professionals ranged from 15% to 95%, and the NSC criterion was not met. There were no cost-effectiveness studies, but a Markov model of a pilot intervention to increase identification of survivors of partner violence in general practice found that such an intervention was potentially cost-effective. CONCLUSIONS: Currently there is insufficient evidence to implement a screening programme for partner violence against women either in health services generally or in specific clinical settings. Recommendations for further research include: trials of system-level interventions and of psychological and advocacy interventions; trials to test theoretically explicit interventions to help understand what works for whom, when and in what contexts; qualitative studies exploring what women want from interventions; cohort studies measuring risk factors, resilience factors and the lifetime trajectory of partner violence; and longitudinal studies measuring the long-term prognosis for survivors of partner violence.


Subject(s)
Mass Screening/standards , Spouse Abuse/diagnosis , Attitude of Health Personnel , Female , Health Services , Humans , Mass Screening/methods , Patient Acceptance of Health Care , Spouse Abuse/prevention & control , United Kingdom
19.
Sante ; 17(2): 69-73, 2007.
Article in French | MEDLINE | ID: mdl-17962153

ABSTRACT

This study was conducted in 2003 as part of the training of laboratory technicians in the use of rapid diagnostic tests (RDTs) for malaria and to evaluate these tests in Madagascar in field conditions for the first time. Two types of RDT were used separately. The dipstick (Optimal-I) that detects circulating pLDH was tested in 168 patients with clinically suspected malaria (fever or recent history of fever) at primary health centers. Microscopy confirmed malaria in 93/168 (55.4%) cases. Monoparasitic P. falciparum infection was identified in 86/93, P. malariae in 3/93, P. vivax in 3/93 and P. ovale in 1/93. A positive Optimal-I test was a highly sensitive indicator of P. falciparum infection with parasitemia exceeding 500 trophozoites/mul (sensitivity of 97.2%; with a specificity of 100%); it also confirmed 6/7 cases of non-P. falciparum malaria. A community malaria survey used the Malaria Hexagon dipstick (detecting P. falciparum-specific HRP2) for 273 patients: 17 (6.2%) RDT tests were positive, and 16 (5.9%) microscopic tests. Although this dipstick did not detect the only case of infection with P. vivax, its specificity was 100% for detection of P. falciparum infection. Installing microscopes and qualified microscopists in the health centers of the one hundred and eleven districts in Madagascar would be extremely difficult, but our results show that RDT is an effective alternative diagnostic tool for daily use as well as for sporadic malaria epidemics. The revised antimalarial treatment policy, involving a drug ten to twenty times more expensive than chloroquine, demonstrates the need to improve malaria diagnosis: presumptive treatment has become prohibitively expensive. RDT can be used to improve malaria case management at the primary heath centers in Madagascar. We discuss the choice of RDTs.


Subject(s)
Malaria/diagnosis , Adult , Aged , Child , Diagnostic Tests, Routine/methods , Humans , Madagascar , Malaria/blood , Time Factors
20.
Phytochemistry ; 54(3): 325-36, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10870188

ABSTRACT

The contents of the pollen lipids of the sunflower Helianthus annuus are described. The major component is the seco-triterpene helianyl octanoate, followed by new beta-diketones as second major group of compounds. They exhibit a shorter chain length and often other positions of the functional group compared to already known beta-diketones. Of particular note are the 1-phenyl-beta-diketones, not previously reported from nature. Further lipid classes present are related hydroxyketones and diols. Interestingly, new beta-dioxoalkanoic acids are present in the extracts, which most likely are biogenetic precursors of the diketones. Additionally, we investigated the composition of the pollen coat which resembles the total extract, but lacks the dioxoalkanoic acids and certain estolides.


Subject(s)
Helianthus/chemistry , Lipids/chemistry , Pollen/chemistry , Chromatography, Gas , Fatty Acids/analysis , Ketones/analysis , Ketones/chemistry , Lipids/analysis , Magnetic Resonance Spectroscopy , Mass Spectrometry , Models, Molecular , Molecular Conformation , Molecular Structure
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