Correction: Outcome of acute bacterial meningitis among children in Kandahar, Afghanistan: A prospective observational cohort study

[This corrects the article DOI: 10.1371/journal.pone.0265487.].

Prevalence of soil-transmitted helminths and associated risk factors among primary school children in Kandahar, Afghanistan: A cross-sectional analytical study

BACKGROUND

Soil-transmitted helminth (STH) infections are global health problem, especially in low-income countries. Main objectives of this study were to estimate the prevalence and intensity of STH and its risk factors among school children in Kandahar city of Afghanistan.

METHODOLOGY/PRINCIPAL FINDINGS

This was a school-based cross-sectional analytical study, with data collected during eight-month-period (May-December, 2022) from 6- and 12-years old school children in Kandahar city, Afghanistan. All the stool samples were examined by saline wet mount method and Kato-Katz technique. Data were analyzed by using descriptive statistics, Chi square test, and multivariate logistic regression. A total of 1275 children from eight schools of Kandahar city were included in this study. Mean age of these children was 8.3 years with 53.3% boys. The overall prevalence of any intestinal parasitic infection was 68.4%. The overall prevalence of STH infection was 39.1%, with Ascaris lumbricoides (29.4%) as the most prevalent STH species. Mean intensity of overall STH infection was 97.8. Multivariate logistic regression revealed playing barefoot (AOR 1.6, 95% CI 1.1-2.2), not washing hands after defecating and before eating (AOR 1.3, 95% CI 1.0-1.7), having untrimmed nails (AOR 1.4, 95% CI 1.1-1.8), and belonging to poor families (AOR 1.3, 95% CI 1.0-1.7) as the risk factors associated with the predisposition of school children for getting STH in Kandahar city of Afghanistan.

CONCLUSIONS/SIGNIFICANCE

There is high prevalence of STH among school children of Kandahar city in Afghanistan. Most of the risk factors are related to poverty, decreased sanitation, and improper hygiene. Improvement of socioeconomic status, sanitation, and health education to promote public awareness about health and hygiene together with periodic mass deworming programs are better strategies for the control of STH infections in Afghanistan.

Responsive Sensory Evaluation to Develop Flexible Taste-Masked Paediatric Primaquine Tablets against Malaria for Low-Resource Settings

Primaquine is an important antimalarial drug for malaria transmission blocking and radical cure, but it is not currently available in child-friendly formulations in appropriate doses. Adult-strength tablets are often crushed and dissolved in water to obtain the required dose, which exposes the drug's bitter taste. As part of the developing paediatric primaquine (DPP) project, this study adopted a responsive sensory pharmaceutics approach by integrating real-time formulation development and pre-clinical taste assessment to develop palatable, flavour-infused primaquine tablets. A design of experiment (DoE) approach was used to screen different taste-masking agents and excipient blends with trained, expert sensory assessors, with quinine hydrochloride as a model bitter tastant. The taste-masking efficacy of selected prototype formulation blends was validated with naïve assessors using the highest 15 mg primaquine dose. The mean bitterness intensity rating, measured on a discrete 11-point scale, was halved from 7.04 for the unflavoured control to 2.74-3.70 for the formulation blends. Sucralose had the biggest impact on bitterness suppression and improving palatability. Two different flavouring systems have been developed, and their acceptability in paediatric patients will be assessed as part of upcoming validation field clinical trials in Africa.

Variability in white blood cell count during uncomplicated malaria and implications for parasite density estimation: a WorldWide Antimalarial Resistance Network individual patient data meta-analysis

BACKGROUND

The World Health Organization (WHO) recommends that when peripheral malarial parasitaemia is quantified by thick film microscopy, an actual white blood cell (WBC) count from a concurrently collected blood sample is used in calculations. However, in resource-limited settings an assumed WBC count is often used instead. The aim of this study was to describe the variability in WBC count during acute uncomplicated malaria, and estimate the impact of using an assumed value of WBC on estimates of parasite density and clearance.

METHODS

Uncomplicated malaria drug efficacy studies that measured WBC count were selected from the WorldWide Antimalarial Resistance Network data repository for an individual patient data meta-analysis of WBC counts. Regression models with random intercepts for study-site were used to assess WBC count variability at presentation and during follow-up. Inflation factors for parasitaemia density, and clearance estimates were calculated for methods using assumed WBC counts (8000 cells/µL and age-stratified values) using estimates derived from the measured WBC value as reference.

RESULTS

Eighty-four studies enrolling 27,656 patients with clinically uncomplicated malaria were included. Geometric mean WBC counts (× 1000 cells/µL) in age groups < 1, 1-4, 5-14 and ≥ 15 years were 10.5, 8.3, 7.1, 5.7 and 7.5, 7.0, 6.5, 6.0 for individuals with falciparum (n = 24,978) and vivax (n = 2678) malaria, respectively. At presentation, higher WBC counts were seen among patients with higher parasitaemia, severe anaemia and, for individuals with vivax malaria, in regions with shorter regional relapse periodicity. Among falciparum malaria patients, using an assumed WBC count of 8000 cells/µL resulted in parasite density underestimation by a median (IQR) of 26% (4-41%) in infants < 1 year old but an overestimation by 50% (16-91%) in adults aged ≥ 15 years. Use of age-stratified assumed WBC values removed systematic bias but did not improve precision of parasitaemia estimation. Imprecision of parasite clearance estimates was only affected by the within-patient WBC variability over time, and remained < 10% for 79% of patients.

CONCLUSIONS

Using an assumed WBC value for parasite density estimation from a thick smear may lead to underdiagnosis of hyperparasitaemia and could adversely affect clinical management; but does not result in clinically consequential inaccuracies in the estimation of the prevalence of prolonged parasite clearance and artemisinin resistance.

Safety of age-dosed, single low-dose primaquine in children with glucose-6-phosphate dehydrogenase deficiency who are infected with Plasmodium falciparum in Uganda and the Democratic Republic of the Congo: a randomised, double-blind, placebo-controlled, non-inferiority trial

BACKGROUND

WHO recommends gametocytocidal, single low-dose primaquine for blocking the transmission of Plasmodium falciparum; however, safety concerns have hampered the implementation of this strategy in sub-Saharan Africa. We aimed to investigate the safety of age-dosed, single low-dose primaquine in children from Uganda and the Democratic Republic of the Congo.

METHODS

We conducted this randomised, double-blind, placebo-controlled, non-inferiority trial at the Mbale Regional Referral Hospital, Mbale, Uganda, and the Kinshasa Mahidol Oxford Research Unit, Kinshasa, Democratic Republic of the Congo. Children aged between 6 months and 11 years with acute uncomplicated P falciparum infection and haemoglobin concentrations of at least 6 g/dL were enrolled. Patients were excluded if they had a comorbid illness requiring inpatient treatment, were taking haemolysing drugs for glucose-6-phosphate dehydrogenase (G6PD) deficiency, were allergic to the study drugs, or were enrolled in another clinical trial. G6PD status was defined by genotyping for the G6PD c.202T allele, the cause of the G6PD-deficient A- variant. Participants were randomly assigned (1:1) to receive single low-dose primaquine combined with either artemether-lumefantrine or dihydroartemisinin-piperaquine, dosed by bodyweight. Randomisation was stratified by age and G6PD status. The primary endpoint was the development of profound (haemoglobin <4 g/dL) or severe (haemoglobin <5 g/dL) anaemia with severity features, within 21 days of treatment. Analysis was by intention to treat. The sample size assumed an incidence of 1·5% in the placebo group and a 3% non-inferiority margin. The trial is registered at ISRCTN, 11594437, and is closed to new participants.

FINDINGS

Participants were recruited at the Mbale Regional Referral Hospital between Dec 18, 2017, and Oct 7, 2019, and at the Kinshasa Mahidol Oxford Research Unit between July 17, 2017, and Oct 5, 2019. 4620 patients were assessed for eligibility. 3483 participants were excluded, most owing to negative rapid diagnostic test or negative malaria slide (n=2982). 1137 children with a median age of 5 years were enrolled and randomly assigned (286 to the artemether-lumefantrine plus single low-dose primaquine group, 286 to the artemether-lumefantrine plus placebo group, 283 to the dihydroartemisinin-piperaquine plus single low-dose primaquine group, and 282 to the dihydroartemisinin-piperaquine plus placebo group). Genotyping of G6PD identified 239 G6PD-c.202T hemizygous males and 45 G6PD-c.202T homozygous females (defining the G6PD-deficient group), 119 heterozygous females, 418 G6PD-c.202C normal males and 299 G6PD-c.202C normal females (defining the non-G6PD-deficient group), and 17 children of unknown status. 67 patients were lost to follow-up and four patients withdrew during the study-these numbers were similar between groups. No participants developed profound anaemia and three developed severe anaemia: from the G6PD-deficient group, none (0%) of 133 patients who received placebo and one (0·66%) of 151 patients who received primaquine (difference -0·66%, 95% CI -1·96 to 0·63; p=0·35); and from the non-G6PD-deficient group, one (0·23%) of 430 patients who received placebo and one (0·25%) of 407 patients who received primaquine (-0·014%, -0·68 to 0·65; p=0·97).

INTERPRETATION

Gametocytocidal, age-dosed, single low-dose primaquine was well tolerated in children from Uganda and the Democratic Republic of the Congo who were infected with P falciparum, and the safety profile of this treatment was similar to that of the placebo. These data support the wider implementation of single low-dose primaquine in Africa.

FUNDING

UK Government Department for International Development, UK Medical Research Council, UK National Institute for Health Research, and the Wellcome Trust Joint Global Health Trials Scheme.

Challenges in antenatal care utilization in Kandahar, Afghanistan: A cross-sectional analytical study

BACKGROUND

Quality antenatal care (ANC) is one of the four pillars of safe motherhood initiatives and improves the survival and health of mother and neonate. The main objective of this study was to assess the barriers in the utilization of ANC services in Kandahar, Afghanistan.

METHODS

This was a cross-sectional analytical study conducted over one year from December 2018-November 2019. Data were analyzed by descriptive statistics, Chi squared, and binary logistic regression.

RESULTS

A total of 1524 women were recruited in this study with mean age of 30.3 years. Of these women, 848 (55.6%) were rural dwellers, 1450/1510 (96.0%) were illiterate, 438/608 (72.0%) belonged to low-income families, 1112/1508 (73.7%) lived in joint families, 1420/1484 (95.7%) lived in a house of >10 inhabitants, while 388/1494 (26.0%) had attended had at least one ANC visit during their last pregnancy. On univariate analysis, the main barriers in the utilization of ANC services were living in rural areas, being illiterate, having lower socio-economic status, remoteness of the health facility from home, bad behavior of clinic personnel, and unplanned pregnancy. Only lower socio-economic status and bad behavior of clinic personnel were independent explanatory variables in the regression model.

CONCLUSIONS

Utilization of ANC services is inadequate in Kandahar province. Improving clinic staff professional behavior and status of women by expanding educational opportunities, and enhancing community awareness of the value of ANC are recommended.

Treatment outcomes and risk factors of death in childhood tuberculous meningitis in Kandahar, Afghanistan: a prospective observational cohort study

BACKGROUND

Tuberculous meningitis (TBM) is the most severe form of TB. We prospectively documented the treatment outcomes and the risk factors for death in children with TBM from Kandahar, Afghanistan.

METHODS

This prospective observational cohort study was conducted from February 2017 to January 2020 in hospitalised TBM children. All the patients were prospectively followed up for 12 mo. Data were analysed by using descriptive statistics, χ2 and multivariate logistic regression.

RESULTS

A total of 818 TBM hospitalised patients with median age 4.8 (0.8-14.5) y were recruited. Females accounted for 60.9% (498/818). Upon admission 53.9% (n=441) and 15.2% (n=124) had TBM stages II and III, respectively, and 23.2% (n=190) had focal neurological signs. The case fatality rate was 20.2% (160/794) and 30.6% (243/794) survived with neurological sequelae. Independent risk factors for death were being unvaccinated for BCG (adjusted OR [AOR] 3.8, 95% CI 1.8 to 8.1), not receiving dexamethasone (AOR 2.5, 95% CI 1.5 to 4.2), being male (AOR 2.3, 95% CI 1.5 to 3.6), history of recent weight loss (AOR 2.2, 95% CI 1.3 to 3.9) and having stage III TBM (AOR 2.0, 95% CI 1.2 to 3.3).

CONCLUSIONS

TBM continues to cause high morbidity and mortality in Afghan children. Strategies to reduce mortality should emphasise early diagnosis and treatment, routine use of dexamethasone and increased BCG vaccination.

Prevalence and associated risk factors of soil-transmitted helminth infections in Kandahar, Afghanistan

Background

Soil-transmitted helminth (STH) infections are still a major health problem, especially in resource-limited countries. The community-based prevalence of STH is unknown in Afghanistan. Main objectives of this study were to estimate the prevalence and associated factors of STH among children in Daman district of Kandahar province in Afghanistan.

Methods

This was a community-based cross-sectional study, with data collected during five months (June–October, 2020) from children living in five villages of Daman district in Kandahar, Afghanistan. All the stool samples were examined by saline wet mount method. Data were analyzed by using descriptive statistics, Chi square test, and multivariate logistic regression.

Results

A total of 1426 children were studied, with majority (61.8%) of males and the mean age of 6.3 years. The overall prevalence of any intestinal parasitic infection was 39.8%. The overall prevalence of STH infection was 22.7%, with Ascaris lumbricoides (18.7%) as the most prevalent STH species, followed by hookworm (7.5%) and Trichuris trichiura (1.4%). Single, double, and triple STH infections were present in 14.9%, 7.2%, and 0.6% of the children, respectively. Multivariate logistic regression revealed that not washing hands after defecating/before eating (AOR 7.0, 95% CI 3.4–14.0), living in mud house (AOR 3.5, 95% CI 1.6–7.4), walking barefoot (AOR 2.2, 95% CI 1.6–3.1), living in overcrowded house (AOR 1.6, 95% CI 1.1–2.3), and practicing open defecation (AOR 1.4, 95% CI 1.1–2.0) as the risk factors associated with the predisposition of rural children for getting STH in Daman district of Afghanistan.

Conclusions

Prevalence of STH is high among children of Daman district in Afghanistan. Most of the risk factors are related to poverty, decreased sanitation, and improper hygiene. Improvement of socioeconomic status, sanitation, and health education to promote public awareness about health and hygiene together with periodic mass deworming programs are better strategies for the control of STH infections in Afghanistan. Also, government and international donor agencies in Afghanistan should help in improving socio-economic status of the rural areas through provision of basic facilities such as piped water, electricity, good housing, and proper toilets.

Outcome of acute bacterial meningitis among children in Kandahar, Afghanistan: A prospective observational cohort study

BACKGROUND

Acute bacterial meningitis (ABM) is an important cause of morbidity and mortality in children but there are no published data on the treatment outcomes of ABM in Afghanistan.

METHODS

We conducted a prospective observational cohort study over one year, February 2020 to January 2021 in a tertiary care hospital in Kandahar, Afghanistan. AMB was diagnosed clinically and on lumbar puncture findings. Binary logistic regression assessed factors for death.

RESULTS

A total of 393 ABM children of mean age 4.8 years were recruited. Most were males [231 (58.8%)], living in rural areas [267 (67.9%)] and in households of >10 inhabitants [294 (74.8%)]. Only 96 (24.4%) had received against both Haemophilus influenzae type b (Hib) or pneumococcal (PCV) vaccines. Children were treated with combination of ceftriaxone and ampicillin and 169/321 (52.6%) received dexamethasone. Of the 321 children with a known outcome, 69 (21.5%) died. Death was significantly associated with: not receiving dexamethasone [adjusted odds ratio (AOR) 4.9 (95% CI 2.6-9.5, p <0.001)], coma on admission [AOR 4.6 (I 2.3-9.5, p <0.001)], no PCV [AOR 2.8 (1.2-6.6, p = 0.019)] or Hib vaccine [AOR 2.8 (1.2-6.6, p = 0.019)], and being male [AOR 2.7 (1.4-5.5, p = 0.005).

CONCLUSIONS

ABM causes significant morbidity and mortality in Afghan children that may be improved by greater use of PCV and Hib vaccines. Adjunct dexamethasone should be evaluated formally in our setting.

Haematological consequences of acute uncomplicated falciparum malaria: a WorldWide Antimalarial Resistance Network pooled analysis of individual patient data

BACKGROUND

Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia.

METHODS

Individual patient data from eligible antimalarial efficacy studies of uncomplicated P. falciparum malaria, available through the WorldWide Antimalarial Resistance Network data repository prior to August 2015, were pooled using standardised methodology. The haematological response over time was quantified using a multivariable linear mixed effects model with nonlinear terms for time, and the model was then used to estimate the mean haemoglobin at day of nadir and day 7. Multivariable logistic regression quantified risk factors for moderately severe anaemia (haemoglobin < 7 g/dL) at day 0, day 3 and day 7 as well as a fractional fall ≥ 25% at day 3 and day 7.

RESULTS

A total of 70,226 patients, recruited into 200 studies between 1991 and 2013, were included in the analysis: 50,859 (72.4%) enrolled in Africa, 18,451 (26.3%) in Asia and 916 (1.3%) in South America. The median haemoglobin concentration at presentation was 9.9 g/dL (range 5.0-19.7 g/dL) in Africa, 11.6 g/dL (range 5.0-20.0 g/dL) in Asia and 12.3 g/dL (range 6.9-17.9 g/dL) in South America. Moderately severe anaemia (Hb < 7g/dl) was present in 8.4% (4284/50,859) of patients from Africa, 3.3% (606/18,451) from Asia and 0.1% (1/916) from South America. The nadir haemoglobin occurred on day 2 post treatment with a mean fall from baseline of 0.57 g/dL in Africa and 1.13 g/dL in Asia. Independent risk factors for moderately severe anaemia on day 7, in both Africa and Asia, included moderately severe anaemia at baseline (adjusted odds ratio (AOR) = 16.10 and AOR = 23.00, respectively), young age (age < 1 compared to ≥ 12 years AOR = 12.81 and AOR = 6.79, respectively), high parasitaemia (AOR = 1.78 and AOR = 1.58, respectively) and delayed parasite clearance (AOR = 2.44 and AOR = 2.59, respectively). In Asia, patients treated with an artemisinin-based regimen were at significantly greater risk of moderately severe anaemia on day 7 compared to those treated with a non-artemisinin-based regimen (AOR = 2.06 [95%CI 1.39-3.05], p < 0.001).

CONCLUSIONS

In patients with uncomplicated P. falciparum malaria, the nadir haemoglobin occurs 2 days after starting treatment. Although artemisinin-based treatments increase the rate of parasite clearance, in Asia they are associated with a greater risk of anaemia during recovery.

Can tibio-femoral kinematic and kinetic parameters reveal poor functionality and underlying deficits after total knee replacement? A systematic review

BACKGROUND

Extensive efforts have been made to understand joint kinematics and kinetics in total knee arthroplasty (TKA) in subjects with satisfactory outcomes during daily functional activities and clinical tests, but it remains unclear whether such movement characteristics hold the potential to indicate the underlying aetiology of unsatisfactory or bad TKA outcomes.

PURPOSE

To investigate which kinematic and kinetic parameters assessed during passive clinical tests and functional activities of daily living are associated with poor functionality and underlying deficits after total knee replacement.

METHODS

We focused on studies characterizing the kinematic or kinetic parameters of the knee joint that are associated with poor clinical outcome after TKA. Seventeen articles were included for the review, and kinematic and kinetic data from 719 patients with minimal follow up of 6 months were extracted and analyzed.

RESULTS

Passive posterior translation at 90°flexionexhibited good potential for differentiating stable and unstable TKAs. Anterior-posterior (A-P) translation of the medial condyle at 0-30° and 30-60° flexion, A-P translation of the lateral condyle at 60-90°during closed chain exercises, as well asknee extension moment during stair ascent and descent, knee abduction moment during stair descent, knee internal rotation moment and plantar flexion moment during walking, 2ndpeak ground reaction force during stair ascent and walkingshowed the greatest promise as functional biomarkers for a dissatisfied/poor outcome knee after TKA.

CONCLUSION

In this study, we systematically reviewed the state-of-the-art knowledge of kinematics and kinetics associated with functional deficits, and found 11 biomechanical parameters that showed promise for supportingdecision making in TKA.

In Vivo Elongation Patterns of the Collateral Ligaments in Healthy Knees During Functional Activities

BACKGROUND

Improved knowledge of in vivo function of the collateral ligaments is essential for enhancing rehabilitation and guiding surgical reconstruction as well as soft-tissue balancing in total knee arthroplasty. The aim of this study was to quantify in vivo elongation patterns of the collateral ligaments throughout complete cycles of functional activities.

METHODS

Knee kinematics were measured using radiographic images captured with a mobile fluoroscope while healthy subjects performed level walking, downhill walking, and stair descent. The registered in vivo tibiofemoral kinematics were then used to drive subject-specific multibody knee models to track collateral ligament elongation.

RESULTS

The elongation patterns of the medial collateral ligament varied distinctly among its bundles, ranging from lengthening of the anterior fibers to shortening of the posterior bundle with increases in the knee flexion angle. The elongation patterns of the lateral collateral ligament varied considerably among subjects. It showed an average 4% shortening with increasing flexion until 60% to 70% of the gait cycle, and then recovered during the terminal-swing phase until reaching its reference length (defined at heel strike).

CONCLUSIONS

The observed nonuniform elongation of the medial collateral ligament bundles suggests that single-bundle reconstruction techniques may not fully restore healthy ligament function. Moreover, the observed ligament elongation patterns indicate greater varus than valgus laxity in the loaded knee.

CLINICAL RELEVANCE

Through providing key knowledge about the in vivo elongation patterns of the collateral ligaments throughout complete cycles of functional activities, this study offers in vivo evidence for benchmarking ligament reconstruction and soft-tissue balancing in total knee arthroplasty.

The Geographical Distribution of Cutaneous Leishmaniasis Causative Agents in Iran and Its Neighboring Countries, A Review

Leishmania tropica and Leishmania major are both the main cause of anthroponotic (ACL) and zoonotic cutaneous leishmaniasis (ZCL), respectively, in the Old World. Leishmania infantum and Leishmania donovani, which are important causes of visceral leishmaniasis, have also occasionally been reported in CL patients. The present study investigates the current distribution of causative species of CL in Iran and neighboring countries in the Middle East. There has been expansion of L. tropica into new urban and rural foci in Iran, with well-documented cases of visceralization, a substantial increase of CL in Syria, and the emergence of new foci and outbreaks in Turkey and Iraq, especially due to L. major. Civil war in Syria and Iraq, population movement, poverty, and climatic change play important roles in the changing CL distribution in this region. Control programs should adopt a multidisciplinary approach based on active surveillance and case finding, especially in vulnerable refugee populations, determination of hazard maps for CL hot points using GIS and other advanced technology, the free distribution of drugs, rodent control, and greater community engagement in poor and marginalized populations. Comprehensive molecular studies that could show the species and strains of Leishmania in different areas of each country can give a better view from the distribution of CL in this region.

Emerging Trends in Clinical Tropical Medicine Research

The American Society for Tropical Medicine and Hygiene recently inaugurated an award for the best clinical research article published in the society’s journal in the previous year. This article summarizes both the process of selecting the winner and several themes that stood out in those articles which rose to the top for consideration. Themes of note included the importance of doing clinical research outside of referral centers, the complexity that must be considered when implementing interventions, incorporation of both ends of the age spectrum into studies, and considering cost-effectiveness and opportunity cost of interventions.

Contribution to Malaria Transmission of Symptomatic and Asymptomatic Parasite Carriers in Cambodia

Background

Eliminating falciparum malaria in Cambodia is a top priority, requiring the implementation of novel tools and strategies to interrupt its transmission. To date, few data are available regarding the contributions to malaria transmission of symptomatic and asymptomatic carriers.

Methods

Direct-membrane and skin feeding assays (DMFAs, SFAs) were performed, using Anopheles minimus and Anopheles dirus, to determine infectivity of symptomatic falciparum-infected patients and malaria asymptomatic carriers; a subset of the latter were followed up for 2 months to assess their transmission potential.

Results

By microscopy and real-time polymerase chain reaction, Plasmodium falciparum gametocyte prevalence rates were, respectively, 19.3% (n = 21/109) and 44% (n = 47/109) on day (D) 0 and 17.9% (n = 5/28) and 89.3% (n = 25/28) in recrudescent patients (Drec) (RT-PCR Drec vs D0 P = .002). Falciparum malaria patient infectivity was low on D0 (6.2%; n = 3/48) and in Drec (8.3%; n = 1/12). Direct-membrane feeding assays and SFAs gave similar results. None of the falciparum (n = 0/19) and 3 of 28 Plasmodium vivax asymptomatic carriers were infectious to mosquitoes, including those that were followed up for 2 months. Overall, P. falciparum gametocytemias were low except in a few symptomatic carriers.

Conclusions

Only symptomatic falciparum malaria patients were infectious to mosquito vectors at baseline and recrudescence, highlighting the need to detect promptly and treat effectively P. falciparum patients.

The tolerability of single low dose primaquine in glucose-6-phosphate deficient and normal falciparum-infected Cambodians

Background

The WHO recommends single low-dose primaquine (SLDPQ, 0.25 mg/kg body weight) in falciparum-infected patients to block malaria transmission and contribute to eliminating multidrug resistant Plasmodium falciparum from the Greater Mekong Sub region (GMS). However, the anxiety regarding PQ-induced acute haemolytic anaemia in glucose-6-phosphate dehydrogenase deficiency (G6PDd) has hindered its use. Therefore, we assessed the tolerability of SLDPQ in Cambodia to inform national policy.

Methods

This open randomised trial of dihydroartemisinin-piperaquine (DHAPP) + SLDPQ vs. DHAPP alone recruited Cambodians aged ≥1 year with acute uncomplicated P. falciparum. Randomisation was 4:1 DHAPP+SLDPQ: DHAPP for G6PDd patients and 1:1 for G6PDn patients, according to the results of the qualitative fluorescent spot test. Definitive G6PD status was determined by genotyping. Day (D) 7 haemoglobin (Hb) concentration was the primary outcome measure.

Results

One hundred nine patients (88 males, 21 females), aged 4–76 years (median 23) were enrolled; 12 were G6PDd Viangchan (9 hemizygous males, 3 heterozygous females). Mean nadir Hb occurred on D7 [11.6 (range 6.4 ─ 15.6) g/dL] and was significantly lower (p = 0.040) in G6PDd (n = 9) vs. G6PDn (n = 46) DHAPP+SLDPQ recipients: 10.9 vs. 12.05 g/dL, Δ = -1.15 (95% CI: -2.24 ─ -0.05) g/dL. Three G6PDn patients had D7 Hb concentrations < 8 g/dL; D7-D0 Hbs were 6.4 ─ 6.9, 7.4 ─ 7.4, and 7.5 ─ 8.2 g/dL.

For all patients, mean (range) D7-D0 Hb decline was -1.45 (-4.8 ─ 2.4) g/dL, associated significantly with higher D0 Hb, higher D0 parasitaemia, and receiving DHAPP; G6PDd was not a factor. No patient required a blood transfusion.

Conclusions

DHAPP+SLDPQ was associated with modest Hb declines in G6PD Viangchan, a moderately severe variant. Our data augment growing evidence that SLDPQ in SE Asia is well tolerated and appears safe in G6PDd patients. Cambodia is now deploying SLDPQ and this should encourage other GMS countries to follow suit.

Trial registration

The clinicaltrials.gov reference number is NCT02434952.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3862-1) contains supplementary material, which is available to authorized users.

Tibio-Femoral Contact Force Distribution is Not the Only Factor Governing Pivot Location after Total Knee Arthroplasty

Total knee arthroplasty aims to mimic the natural knee kinematics by optimizing implant geometry, but it is not clear how loading relates to tibio-femoral anterior-posterior translation or internal-external pivoting. We hypothesised that the point of pivot in the transverse plane is governed by the location of the highest axial force. Tibio-femoral loading was measured using an instrumented tibial component in six total knee arthroplasty patients (aged 65–80y, 5–7y post-op) during 5–6 squat repetitions, while knee kinematics were captured using a mobile video-fluoroscope. In the range of congruent tibio-femoral contact the medial femoral condyle remained approximately static while the lateral condyle translated posteriorly by 4.1 mm (median). Beyond the congruent range, the medial and lateral condyle motions both abruptly changed to anterior sliding by 4.6 mm, and 2.6 mm respectively. On average, both the axial loading and pivot position were more medial near extension, and transferred to the lateral side in flexion. However, no consistent relationship between pivoting and load distribution was found across all patients throughout flexion, with R² values ranging from 0.00 to 0.65. Tibio-femoral kinematics is not related to the load distribution alone: medial loading of the knee does not necessarily imply a medial pivot location.

Population structures of Leishmania infantum and Leishmania tropica the causative agents of kala-azar in Southwest Iran

Visceral leishmaniasis (VL) is endemic in Iran and is caused predominantly by Leishmania infantum, but L. tropica is emerging as an important cause. We studied the intra-species population structure of Leishmania spp. causing VL in southwest Iran by sequence analysis of the internal transcribed spacer (ITS) 1 of DNA samples from 29 bone marrow aspiration smears. L. infantum (n = 25) and L. tropica (n = 4) were identified, consisting of 10 and three ITS1 sequence types (STs), respectively. Compared to GenBank ITS1 STs, our L. infantum parasites displayed high heterogeneity but less heterogeneity compared than northwest Iranian isolates. VL affects mostly nomadic populations in southwest Iran, and their mobility may explain partly the L. infantum heterogeneity. The VL causing L. tropica was also genetically heterogeneous but genetically indistinguishable from L. tropica strains causing anthroponotic cutaneous leishmaniasis from southwest Iran.

Quantifying primaquine effectiveness and improving adherence: a round table discussion of the APMEN Vivax Working Group

The goal to eliminate malaria from the Asia-Pacific by 2030 will require the safe and widespread delivery of effective radical cure of malaria. In October 2017, the Asia Pacific Malaria Elimination Network Vivax Working Group met to discuss the impediments to primaquine (PQ) radical cure, how these can be overcome and the methodological difficulties in assessing clinical effectiveness of radical cure. The salient discussions of this meeting which involved 110 representatives from 18 partner countries and 21 institutional partner organizations are reported. Context specific strategies to improve adherence are needed to increase understanding and awareness of PQ within affected communities; these must include education and health promotion programs. Lessons learned from other disease programs highlight that a package of approaches has the greatest potential to change patient and prescriber habits, however optimizing the components of this approach and quantifying their effectiveness is challenging. In a trial setting, the reactivity of participants results in patients altering their behaviour and creates inherent bias. Although bias can be reduced by integrating data collection into the routine health care and surveillance systems, this comes at a cost of decreasing the detection of clinical outcomes. Measuring adherence and the factors that relate to it, also requires an in-depth understanding of the context and the underlying sociocultural logic that supports it. Reaching the elimination goal will require innovative approaches to improve radical cure for vivax malaria, as well as the methods to evaluate its effectiveness.

Quantitative imaging of deuterated metabolic tracers in biological tissues with nanoscale secondary ion mass spectrometry

In the field of secondary ion mass spectrometry at nanometer scale (NanoSIMS), configuration of parallel detectors to routinely measure isotope ratios in sub-100 nm domains brings classical stable isotope tracer studies from the whole tissue level down to the suborganelle level. Over the past decade, the marriage of stable isotope tracers with NanoSIMS has been applied to a range of fundamental biological questions that were largely inaccessible by other means. Although multiplexed measurement of different stable isotope tracers is feasible, in practice there remains a gap in the current analytical capacity to efficiently measure stable isotopes commonly utilized in tracer studies. One such example is the measurement of deuterated tracers. The most obvious approach to measuring deuterium/hydrogen isotope ratios is at mass 2/1. However, the radius of the magnetic sector limits concomitant measurement of other masses critical to multiplexed exploration of biological samples. Here we determine the experimental parameters to measure deuterated tracers in biological samples using the C₂H^- polyatomic ion species (C₂D^-/C₂H^-) while operating the NanoSIMS at a reduced Mass Resolving Power of 14,000. Through control of the sputtering parameters, we demonstrate that there is an analytical window during which the C₂D^-/C₂H^- isotope ratio can be measured with sufficient precision for biological studies where the degree of D-labeling is typically well above natural abundance. We provide validation of this method by comparing the C₂D measurement of D-water labeling in the murine small intestine relative to measurements of native D/H conducted in the same analytical fields. Additional proof-of-concept demonstrations include measurement of D-water, D-glucose, and D-thymidine in biological specimens. Therefore, this study provides a practical template for deuterium-based tracer studies in biological systems.

Revealing the quality of movement: A meta-analysis review to quantify the thresholds to pathological variability during standing and walking

Neuromotor processes are inherently noisy, which results in variability during movement and fluctuations in motor control. Although controversial, low levels of variability are traditionally considered healthy, while increased levels are thought to be pathological. This systematic review and meta-analysis of the literature investigates the thresholds between healthy and pathological task variability. After examining 13,195 publications, 109 studies were included. Results from over 3000 healthy subjects and 2775 patients revealed an overall positive effect size of pathology on variability of 0.59 for walking and 0.80 for sway. For the coefficient of variation of stride time (ST) and sway area (SA), upper thresholds of 2.6% and 265mm(2) discriminated pathological from asymptomatic performance, while 1.1% and 62mm(2) identified the lower thresholds for pathological variability. This window of healthy performance now provides science based evidence for the discrimination of both extremely low and extremely high levels of variability in the identification as well as standardised monitoring of functional status in neurological cases.

Abstract 145: Microcapsule Delivery of Mesenchymal Stem Cell for Myocardial Regeneration

Following myocardial injury, 1 in 3 patients will have irreversible cardiac damage and develop congestive heart failure. The paracrine factors secreted by mesenchymal stem cells (MSCs) have shown promise in regenerating damaged heart tissue through their pro-angiogenic and anti-inflammatory properties. The beneficial effect of MSCs can be further optimized by their targeted delivery and increased retention within the damaged myocardium.

Objective: To develop a novel cell therapy approach which allows direct infusion of encapsulated mesenchymal stem cells into the coronary circulation without compromising cardiac function.

Methods: Mesenchymal stem cells were encapsulated into polyethylene glycol (PEG) based microparticles (MPs) using microfluidics technology. These encapsulated MSCs were infused ex vivo into the rat coronaries using retrograde perfusion in a Langendorff - isolated heart setup. Rat hearts infused with fluorescently tagged MPs were imaged using Xtreme Optical imaging (Bruker, MA) to evaluate for MP distribution within the tissue. Frozen sections of the MP infused hearts were evaluated for distribution within the coronary microvasculature. To evaluate cardiac function after iterative MP infusion, pressure volume curves were generated using a Millar catheter and recorded on Powerlab (ADI instruments, Australia).

Results: The microfluidics encapsulation process generates microparticles of 30-60 μm diameter with up to 59.7% encapsulation efficiency. Encapsulated MSCs distribute evenly throughout the heart as assessed by whole-organ fluorescence imaging. Systolic function of the rat heart was not compromised when up to 100,000 encapsulated MSCs were infused by retrograde coronary perfusion. Histological sections post infusion showed that the MPs localized to terminal blood vessels as small as 10 μm in diameter, suggesting that these microparticles are compressible and are trapped within small coronary vessels, thereby improving retention.

Conclusion: Intra-coronary perfusion of encapsulated MSCs is a viable and promising approach for the delivery of MSCs after myocardial injury.

Dengue in adults admitted to a referral hospital in Hanoi, Vietnam

Knowledge of adult dengue virus (DENV) infection from Hanoi, Vietnam, is limited. In 2008, we prospectively studied 143 (77 male) confirmed (nonstructural 1 antigen enzyme-linked immunosorbent assay [ELISA], DENV polymerase chain reaction, paired serology) adult dengue patients of median age 23.5 (range 16-72) years. They were admitted to the National Hospital for Tropical Diseases, Hanoi, on median illness day (D) 5 (range 1-8). By D8, 141 (98.6%) were afebrile. Platelet counts and hematocrit (median, interquartile range [IQR]) nadired and peaked on D5 and D4, respectively: 40,000/μL (10,000-109,000/μL), 43.4% (34.9-49.7%). Four (2.8%) patients had severe dengue: 1) D10 shock (N = 1) and 2) aspartate aminotransferase (AST) ≥ 1,000 IU/L (N = 3, D5 and D7). Of 143 patients, 118 (82.5%) had ≥ 1 warning sign (World Health Organization [WHO] 2009 criteria): mucosal bleeding 66/143 (46.1%), soft tissue edema 54/143 (37.7%), and ultrasound detected plasma leakage (pleural effusions/ascites) 30/129 (23.25%). 138 (96.5%) patients received intravenous (IV) fluids: 3 L (IQR: 0.5-8.5 L). Most patients had non-severe dengue with warning signs. High rates of edema and plasma leakage may be explained partly by liberal use of IV fluids. Studies are needed on optimizing fluid management in non-severe adult dengue.

Identification of functional parameters for the classification of older female fallers and prediction of 'first-time' fallers

Falls remain a challenge for ageing societies. Strong evidence indicates that a previous fall is the strongest single screening indicator for a subsequent fall and the need for assessing fall risk without accounting for fall history is therefore imperative. Testing in three functional domains (using a total 92 measures) were completed in 84 older women (60-85 years of age), including muscular control, standing balance, and mean and variability of gait. Participants were retrospectively classified as fallers (n = 38) or non-fallers (n = 42) and additionally in a prospective manner to identify first-time fallers (FTFs) (n = 6) within a 12-month follow-up period. Principal component analysis revealed that seven components derived from the 92 functional measures are sufficient to depict the spectrum of functional performance. Inclusion of only three components, related to mean and temporal variability of walking, allowed classification of fallers and non-fallers with a sensitivity and specificity of 74% and 76%, respectively. Furthermore, the results indicate that FTFs show a tendency towards the performance of fallers, even before their first fall occurs. This study suggests that temporal variability and mean spatial parameters of gait are the only functional components among the 92 measures tested that differentiate fallers from non-fallers, and could therefore show efficacy in clinical screening programmes for assessing risk of first-time falling.

Is gait variability reliable? An assessment of spatio-temporal parameters of gait variability during continuous overground walking

The assessment of gait variability has become an important indicator for quantifying motor performance. However, the use of treadmills is known to influence the temporal rhythm of gait, while non-continuous (i.e. stop-start) overground walking alters gait variability, leading to erroneous results. Through establishing the "8-walk", an overground walking protocol that allows the collection of a high number of consecutive gait cycles, the aim of this study was to determine the conditions under which gait variability can be assessed reliably. Twelve healthy subjects performed continuous barefoot walking at their preferred speed in a path shaped as an "8". Kinematic data of the dominant foot was collected while subjects walked along the straight 10 m sections of the 8-walk during sessions on two different days. Mean spatio-temporal parameters of gait and gait variability were computed for 10, 20, 30, 40, 50 and 60 consecutive cycles. All mean parameters of gait showed excellent reliability (ICC: 0.88-0.98) with only 10 cycles included in the analysis. However, the reliability of spatial and temporal parameters of gait variability improved with increasing number of cycles (ICC: 0.60-0.90) but levelled-off after 50 consecutive cycles, revealing an inter-day test-retest variability of ≈ 13%. To reliably assess gait variability and evaluate human motor performance, we propose the collection of at least 50 cycles and the use of an 8-walk protocol, which avoids the limitations of treadmill and non-consecutive walking protocols.

Fatal respiratory infections associated with rhinovirus outbreak, Vietnam

During an outbreak of severe acute respiratory infections in 2 orphanages, Vietnam, 7/12 hospitalized children died. All hospitalized children and 26/43 children from outbreak orphanages tested positive for rhinovirus versus 9/40 control children (p = 0.0005). Outbreak rhinoviruses formed a distinct genetic cluster. Human rhinovirus is an underappreciated cause of severe pneumonia in vulnerable groups.

The spectrum of central nervous system infections in an adult referral hospital in Hanoi, Vietnam

Objectives

To determine prospectively the causative pathogens of central nervous system (CNS) infections in patients admitted to a tertiary referral hospital in Hanoi, Vietnam.

Methods

From May 2007 to December 2008, cerebrospinal fluid (CSF) samples from 352 adults with suspected meningitis or encephalitis underwent routine testing, staining (Gram, Ziehl-Nielsen, India ink), bacterial culture and polymerase chain reaction targeting Neisseria meningitidis, Streptococcus pneumoniae, S. suis, Haemophilus influenzae type b, Herpes simplex virus (HSV), Varicella Zoster virus (VZV), enterovirus, and 16S ribosomal RNA. Blood cultures and clinically indicated radiology were also performed. Patients were classified as having confirmed or suspected bacterial (BM), tuberculous (TBM), cryptococcal (CRM), eosinophilic (EOM) meningitis, aseptic encephalitis/meningitis (AEM), neurocysticercosis and others.

Results

352 (male: 66%) patients were recruited: median age 34 years (range 13–85). 95/352 (27.3%) diagnoses were laboratory confirmed and one by cranial radiology: BM (n = 62), TBM (n = 9), AEM (n = 19), CRM (n = 5), and neurocysticercosis (n = 1, cranial radiology). S. suis predominated as the cause of BM [48/62 (77.4%)]; Listeria monocytogenese (n = 1), S. pasteurianus (n = 1) and N. meningitidis (n = 2) were infrequent. AEM viruses were: HSV (n = 12), VZV (n = 5) and enterovirus (n = 2). 5 patients had EOM. Of 262/352 (74.4%) patients with full clinical data, 209 (79.8%) were hospital referrals and 186 (71%) had been on antimicrobials. 21 (8%) patients died: TBM (15.2%), AEM (10%), and BM (2.8%).

Conclusions

Most infections lacked microbiological confirmation. S. suis was the most common cause of BM in this setting. Improved diagnostics are needed for meningoencephalitic syndromes to inform treatment and prevention strategies.

Effective marker placement for functional identification of the centre of rotation at the hip

The accuracy and precision of quantifying musculoskeletal kinematics, and particularly determining the centre of rotation (CoR) at the hip joint, using skin marker based motion analysis is limited by soft tissue artefact (STA). We posed the question of whether the contribution of individual markers towards improving the precision of the functional joint centre using marker based methods could be assessed, and then utilised to allow effective marker placement for determination of the CoR at the hip. Sixty-three retro-reflective skin markers were placed to encompass the thighs of seven healthy subjects, together with a set of sixteen markers on the pelvis. The weighted optimal common shape technique (wOCST) was then applied to determine the weighting, or importance, of each marker for identifying the centre of rotation at the hip. The markers with the highest weightings over all subjects and measurements were determined that identified the HJC with the highest precision. The use of six markers in selected regions (two anterior, two lateral and two posterior) allowed the HJC to be determined with a similar precision to the complete set of 63 markers, with the determined regions predominantly distant from the hip joint, excluding areas associated with the bellies of large muscles and therefore large motion artefact from muscle activity. The novel approach presented here allows an understanding of each marker's contribution towards a precise joint determination, and therefore enables the targeted placement of markers for reliable assessment of musculoskeletal kinematics.

Abstract 398: Hydrogen Peroxide Mediates Calcium Chloride--Induced Aortic Wall Dilatation

Rationale: Abdominal aneurysm formation is characterized by infiltration of the aortic wall with inflammatory cells, activation of proteolytic enzymes, loss of vascular smooth muscle cells (VSMC), and neovascularization. It is also known that hydrogen peroxide (H 2 O 2 ) plays an important role in these processes.

Hypothesis: Since H 2 O 2 participates in the pathophysiologic processes that govern aneurysmal dilatation, we hypothesized that scavenging of H 2 O 2 with catalase protects against the formation of aortic aneurysms.

Methods: To assess our hypothesis 3 groups of mice, all 8-10-week-old males on the C57BL6 background, were used. Aortic dilatation was induced with the application of CaCl 2 on the infrarenal aortas. We compared the aortic dilation in mice that specifically over-express catalase in the VSMC (group 1) or in the myeloid cell lineage (MCL) (group 2) with their wild type littermates. Chemical injury with CaCl 2 was also induced in wild type mice which were treated with continuous intravenous infusion of PEG-catalase or saline for 8 weeks (group 3). The aortic diameter was measured with a caliper and with videomicroscopy on the day of surgery and 8 weeks later. H 2 O 2 levels were quantified with the Amplex Red assay.

Results: Application of CaCl 2 resulted in a significant increase in H 2 O 2 generation in the infrarenal aortas compared to saline controls, which peaked on post-operative day 10 (0.60±0.09 vs. 0.37±0.05 μM/aortic ring, n=3/grp, p=0.02). Compared to their wild type littermates, mice that over-express catalase in the VSMC had negligible dilation of the aorta (0.78±0.05 vs. 0.53±0.02 mm, n=7/grp, p=0.001). Similarly, over-expression of catalase in MCL protected against aortic dilation (0.76±0.02 vs. ±0.005 mm, n=7, p<0.0001). Corroborating the above findings, continuous intravenous infusion of PEG-catalase, but not saline, protected from CaCl 2 induced aortic dilation (0.73±0.03 vs.0.56±0.02 mm, n=3-6/grp, p=0.007).

Conclusions: Our data suggest that H 2 O 2 is essential in CaCl 2 induced aortic aneurysm formation.

Evolutionary inaccuracy of pairwise structural alignments

Motivation: Structural alignment methods are widely used to generate gold standard alignments for improving multiple sequence alignments and transferring functional annotations, as well as for assigning structural distances between proteins. However, the correctness of the alignments generated by these methods is difficult to assess objectively since little is known about the exact evolutionary history of most proteins. Since homology is an equivalence relation, an upper bound on alignment quality can be found by assessing the consistency of alignments. Measuring the consistency of current methods of structure alignment and determining the causes of inconsistencies can, therefore, provide information on the quality of current methods and suggest possibilities for further improvement.

Results: We analyze the self-consistency of seven widely-used structural alignment methods (SAP, TM-align, Fr-TM-align, MAMMOTH, DALI, CE and FATCAT) on a diverse, non-redundant set of 1863 domains from the SCOP database and demonstrate that even for relatively similar proteins the degree of inconsistency of the alignments on a residue level is high (30%). We further show that levels of consistency vary substantially between methods, with two methods (SAP and Fr-TM-align) producing more consistent alignments than the rest. Inconsistency is found to be higher near gaps and for proteins of low structural complexity, as well as for helices. The ability of the methods to identify good structural alignments is also assessed using geometric measures, for which FATCAT (flexible mode) is found to be the best performer despite being highly inconsistent. We conclude that there is substantial scope for improving the consistency of structural alignment methods.

Contact:msadows@nimr.mrc.ac.uk

Supplementary information:Supplementary data are available at Bioinformatics online.

Severe pandemic H1N1 2009 infection is associated with transient NK and T deficiency and aberrant CD8 responses

Background

It is unclear why the severity of influenza varies in healthy adults or why the burden of severe influenza shifts to young adults when pandemic strains emerge. One possibility is that cross-protective T cell responses wane in this age group in the absence of recent infection. We therefore compared the acute cellular immune response in previously healthy adults with severe versus mild pandemic H1N1 infection.

Methods and Principal Findings

49 previously healthy adults admitted to the National Hospital of Tropical Diseases, Viet Nam with RT-PCR-confirmed 2009 H1N1 infection were prospectively enrolled. 39 recovered quickly whereas 10 developed severe symptoms requiring supplemental oxygen and prolonged hospitalization. Peripheral blood lymphocyte subset counts and activation (HLADR, CD38) and differentiation (CD27, CD28) marker expression were determined on days 0, 2, 5, 10, 14 and 28 by flow cytometry. NK, CD4 and CD8 lymphopenia developed in 100%, 90% and 60% of severe cases versus 13% (p<0.001), 28%, (p = 0.001) and 18% (p = 0.014) of mild cases. CD4 and NK counts normalized following recovery. B cell counts were not significantly associated with severity. CD8 activation peaked 6–8 days after mild influenza onset, when 13% (6–22%) were HLADR+CD38+, and was accompanied by a significant loss of resting/CD27+CD28+ cells without accumulation of CD27+CD28− or CD27−CD28− cells. In severe influenza CD8 activation peaked more than 9 days post-onset, and/or was excessive (30–90% HLADR+CD38+) in association with accumulation of CD27+CD28− cells and maintenance of CD8 counts.

Conclusion

Severe influenza is associated with transient T and NK cell deficiency. CD8 phenotype changes during mild influenza are consistent with a rapidly resolving memory response whereas in severe influenza activation is either delayed or excessive, and partially differentiated cells accumulate within blood indicating that recruitment of effector cells to the lung could be impaired.

The quality of bone surfaces may govern the use of model based fluoroscopy in the determination of joint laxity

The assessment of knee joint laxity is clinically important but its quantification remains elusive. Calibrated, low dosage fluoroscopy, combined with registered surfaces and controlled external loading may offer possible solutions for quantifying relative tibio-femoral motion without soft tissue artefact, even in native joints. The aim of this study was to determine the accuracy of registration using CT and MRI derived 3D bone models, as well as metallic implants, to 2D single-plane fluoroscopic datasets, to assess their suitability for examining knee joint laxity. Four cadaveric knees and one knee implant were positioned using a micromanipulator. After fluoroscopy, the accuracy of registering each surface to the 2D fluoroscopic images was determined by comparison against known translations from the micromanipulator measurements. Dynamic measurements were also performed to assess the relative tibio-femoral error. For CT and MRI derived 3D femur and tibia models during static testing, the in-plane error was 0.4 mm and 0.9 mm, and out-of-plane error 2.6 mm and 9.3 mm respectively. For metallic implants, the in-plane error was 0.2 mm and out-of-plane error 1.5 mm. The relative tibio-femoral error during dynamic measurements was 0.9 mm, 1.2 mm and 0.7 mm in-plane, and 3.9 mm, 10.4 mm and 2.5 mm out-of-plane for CT and MRI based models and metallic implants respectively. The rotational errors ranged from 0.5° to 1.9° for CT, 0.5-4.3° for MRI and 0.1-0.8° for metallic implants. The results of this study indicate that single-plane fluoroscopic analysis can provide accurate information in the investigation of knee joint laxity, but should be limited to static or quasi-static evaluations when assessing native bones, where possible. With this knowledge of registration accuracy, targeted approaches for the determination of tibio-femoral laxity could now determine objective in vivo measures for the identification of ligament reconstruction candidates as well as improve our understanding of the consequences of knee joint instability in TKA.

Carbonic anhydrase-related protein VIII is expressed in rod bipolar cells and alters signaling at the rod bipolar to AII-amacrine cell synapse in the mammalian retina

Mutation of the gene encoding carbonic anhydrase-related protein VIII (CAVIII) results in motor coordination deficits in mice and humans, due to loss of this protein in Purkinje cells of the cerebellum. Recent studies have indicated that the CAVIII gene, Car8, is also expressed in rod bipolar cells (RBCs), a critical glutamatergic neuron for scotopic vision. We investigated the localization of CAVIII in the mouse and macaque retina, and utilized the wdl mouse, which has a null mutation in the Car8 gene, to determine how the loss of CAVIII affects retinal signaling. CAVIII immunoreactivity was observed in RBCs, with particularly high staining intensity in the axon terminals. In addition, weaker staining was observed in a subset of cone bipolar cells and γ-aminobutyric acid (GABA)ergic amacrine cells. Light-evoked current and voltage responses of RBCs were not altered in the wdl mutant. However, light-evoked current responses from the AII-amacrine cell, a postsynaptic partner at the RBC ribbon synapse, were significantly larger, and more prolonged than in control mice. These changes could not be attributed to alterations in calcium current activation or inactivation, or to changes in the density of RBCs. Furthermore, no gross synaptic alterations were evident in the wdl mutant at the light or ultrastructural level. These data provide evidence that the CAVIII protein, which is highly conserved in vertebrates, is selectively expressed within neural circuits, and may be important for modulating retinal neurotransmission.

Trigger features and excitation in the retina

This review focuses on recent advances in our understanding of how neural divergence and convergence give rise to complex encoding properties of retinal ganglion cells. We describe the apparent mismatch between the number of cone bipolar cell types, and the diversity of excitatory input to retinal ganglion cells, and outline two possible solutions. One proposal is for diversity in the excitatory pathways to be generated within axon terminals of cone bipolar cells, and the second invokes narrow-field glycinergic amacrine cells that can apparently act like bipolar cells by providing excitatory drive to ganglion cells. Finally we highlight two advances in technique that promise to provide future insights; automation of electron microscope data collection and analysis, and the use of the ideal observer to quantitatively compare neural performance at all levels.

Exploring the factors determining the dynamics of different protein folds

Normal mode analyses of homologous proteins at the family and superfamily level show that slow dynamics are similar and are preserved through evolution. This study investigates how the slow dynamics of proteins is affected by variation in the protein architecture and fold. For this purpose, we have used computer-generated protein models based on idealized protein structures with varying folds. These are shown to be protein-like in their behavior, and they are used to investigate the influence of architecture and fold on the slow dynamics. We compared the dynamics of models having different folds but similar architecture and found the architecture to be the dominant factor for the slow dynamics.

Immunological and viral determinants of dengue severity in hospitalized adults in Ha Noi, Viet Nam

Background

The relationships between the infecting dengue serotype, primary and secondary infection, viremia and dengue severity remain unclear. This cross-sectional study examined these interactions in adult patients hospitalized with dengue in Ha Noi.

Methods and Findings

158 patients were enrolled between September 16 and November 11, 2008. Quantitative RT-PCR, serology and NS1 detection were used to confirm dengue infection, determine the serotype and plasma viral RNA concentration, and categorize infections as primary or secondary. 130 (82%) were laboratory confirmed. Serology was consistent with primary and secondary infection in 34% and 61%, respectively. The infecting serotype was DENV-1 in 42 (32%), DENV-2 in 39 (30%) and unknown in 49 (38%). Secondary infection was more common in DENV-2 infections (79%) compared to DENV-1 (36%, p<0.001). The proportion that developed dengue haemorrhagic fever (DHF) was 32% for secondary infection compared to 18% for primary infection (p = 0.14), and 26% for DENV-1 compared to 28% for DENV-2. The time until NS1 and plasma viral RNA were undetectable was shorter for DENV-2 compared to DENV-1 (p≤0.001) and plasma viral RNA concentration on day 5 was higher for DENV-1 (p = 0.03). Plasma viral RNA concentration was higher in secondary infection on day 5 of illness (p = 0.046). We didn't find an association between plasma viral RNA concentration and clinical severity.

Conclusion

Dengue is emerging as a major public health problem in Ha Noi. DENV-1 and DENV-2 were the prevalent serotypes with similar numbers and clinical presentation. Secondary infection may be more common amongst DENV-2 than DENV-1 infections because DENV-2 infections resulted in lower plasma viral RNA concentrations and viral RNA concentrations were higher in secondary infection. The drivers of dengue emergence in northern Viet Nam need to be elucidated and public health measures instituted.

Dengue is estimated to affect 50 million people each year and can occur as explosive outbreaks that overwhelm health systems. Despite significant advances the available knowledge is not sufficient to predict the outcome of individual infections or the occurrence of epidemics. Studies from low dengue transmission settings are lacking but offer the potential to better understand the contribution of age, primary versus secondary infection and serotype because there are likely to be more adult and primary infection patients and fewer serotypes circulating compared to high transmission settings. This is the first reported study of clinical dengue in Ha Noi, the largest urban area of Northern Viet Nam. Records kept by the Preventive Medicine Center indicate that <2500 clinical dengue cases attended government health care facilities in Ha Noi each year from 1999 until 2007. Patients in Ha Noi were older than in high transmission settings, the contribution of primary infection to overt and severe illness was greater and associations between serotype, plasma viral RNA concentration and overt and severe illness were distinct. The dengue situation in Ha Noi provides an opportunity to further examine the roles of serotype and prior immunity in dengue severity and epidemic emergence.

Bioluminescence of Marine Dinoflagellates : I. An underwater photometer for day and night measurements

Portable light-baffled underwater photometers have been designed for the measurement of dinoflagellate bioluminescence by day and night. Maximal light emission is obtained by mechanical stimulation in a defined volume. The pump which stimulates the dinoflagellates also constantly replenishes the sample volume so that continuous measurements are possible. Evidence for both diurnal variation and vertical migration is presented. Using luminous bacteria for calibration a single dinoflagellate has been found to emit of the order of 10(10) light quanta per flash. The technique suggests that large scale mapping of bioluminescence is feasible.

Repeatability and reproducibility of OSSCA, a functional approach for assessing the kinematics of the lower limb

Marker-based gait analysis of the lower limb that uses assumptions of generic anatomical morphology can be susceptible to errors, particularly in subjects with high levels of soft tissue coverage. We hypothesize that a functional approach for assessing skeletal kinematics, based on the application of techniques to reduce soft tissue artefact and functionally identify joint centres and axes, can more reliably (repeatably and reproducibly) assess the skeletal kinematics than a standard generic regression approach. Six healthy adults each performed 100 repetitions of a standardized motion, measured on four different days and by five different observers. Using OSSCA, a combination of functional approaches to reduce soft tissue artefact and identify joint centres and axes, the lengths of the femora and tibiae were determined to assess the inter-day and inter-observer reliability, and compared against a standard generic regression approach. The results indicate that the OSSCA was repeatable and reproducible (ICC lowest bound 0.87), but also provided an improvement over the regression approach (ICC lowest bound 0.69). Furthermore, the analysis of variance revealed a statistically significant variance for the factor "observers" (p<0.01; low-reproducibility) when using the regression approach for determining the femoral lengths. Here, this non-invasive, rapid and robust approach has been demonstrated to allow the repeatable and reproducible identification of skeletal landmarks, which is insensitive to marker placement and measurement session. The reliability of the OSSCA thus allows its application in clinical studies for reducing the uncertainty of approach-induced systematic errors.

Selective activation of mGluR8 receptors modulates retinal ganglion cell light responses

Extracellular and whole-cell light-evoked responses of mouse retinal ganglion cells were recorded in the presence of the mGluR8 selective agonist, (S)-3,4-dicarboxy-phenylglycine (DCPG). Off-light responses were reversibly reduced in the presence of DCPG in wild-type but not in mGluR8-deficient retinas. On-responses were only marginally modulated by DCPG. During Off-responses, DCPG suppressed both excitatory and inhibitory synaptic conductances suggesting that mGluR8 receptor activity reduces glutamate release from bipolar cell terminals and possibly also the release of an inhibitory neurotransmitter from amacrine cell processes.

Minimally invasive thoracic corpectomy and anterior fusion in a patient with metastatic disease: case report and review of the literature

For patients with metastatic disease to the spine there are numerous surgical approaches for decompression of neural elements and maintenance of mechanical stability. The challenge is to accomplish this while minimizing patient morbidity. Here we report on the feasibility and utility of a minimally invasive extreme lateral approach to the mid to high thoracic spine for anterior decompression and fusion.

Different methodological approaches to the assessment of in vivo efficacy of three artemisinin-based combination antimalarial treatments for the treatment of uncomplicated falciparum malaria in African children

Background

Use of different methods for assessing the efficacy of artemisinin-based combination antimalarial treatments (ACTs) will result in different estimates being reported, with implications for changes in treatment policy.

Methods

Data from different in vivo studies of ACT treatment of uncomplicated falciparum malaria were combined in a single database. Efficacy at day 28 corrected by PCR genotyping was estimated using four methods. In the first two methods, failure rates were calculated as proportions with either (1a) reinfections excluded from the analysis (standard WHO per-protocol analysis) or (1b) reinfections considered as treatment successes. In the second two methods, failure rates were estimated using the Kaplan-Meier product limit formula using either (2a) WHO (2001) definitions of failure, or (2b) failure defined using parasitological criteria only.

Results

Data analysed represented 2926 patients from 17 studies in nine African countries. Three ACTs were studied: artesunate-amodiaquine (AS+AQ, N = 1702), artesunate-sulphadoxine-pyrimethamine (AS+SP, N = 706) and artemether-lumefantrine (AL, N = 518).

Using method (1a), the day 28 failure rates ranged from 0% to 39.3% for AS+AQ treatment, from 1.0% to 33.3% for AS+SP treatment and from 0% to 3.3% for AL treatment. The median [range] difference in point estimates between method 1a (reference) and the others were: (i) method 1b = 1.3% [0 to24.8], (ii) method 2a = 1.1% [0 to21.5], and (iii) method 2b = 0% [-38 to19.3].

The standard per-protocol method (1a) tended to overestimate the risk of failure when compared to alternative methods using the same endpoint definitions (methods 1b and 2a). It either overestimated or underestimated the risk when endpoints based on parasitological rather than clinical criteria were applied. The standard method was also associated with a 34% reduction in the number of patients evaluated compared to the number of patients enrolled. Only 2% of the sample size was lost when failures were classified on the first day of parasite recurrence and survival analytical methods were used.

Conclusion

The primary purpose of an in vivo study should be to provide a precise estimate of the risk of antimalarial treatment failure due to drug resistance. Use of survival analysis is the most appropriate way to estimate failure rates with parasitological recurrence classified as treatment failure on the day it occurs.

Tetrahydrobiopterin: a novel antihypertensive therapy

Tetrahydrobiopterin (BH(4)) is a cofactor for the nitric oxide (NO) synthase enzymes, such that its insufficiency results in uncoupling of the enzyme, leading to release of superoxide rather than NO in disease states, including hypertension. We hypothesized that oral BH(4) will reduce arterial blood pressure (BP) and improve endothelial function in hypertensive subjects. Oral BH(4) was given to subjects with poorly controlled hypertension (BP >135/85 mm Hg) and weekly measurements of BP and endothelial function made. In Study 1, 5 or 10 mg kg(-1) day(-1) of BH(4) (n=8) was administered orally for 8 weeks, and in Study 2, 200 and 400 mg of BH(4) (n=16) was given in divided doses for 4 weeks. Study 1: significant reductions in systolic (P=0.005) and mean BP (P=0.01) were observed with both doses of BH(4). Systolic BP was 15+/-15 mm Hg (P=0.04) lower after 5 weeks and persisted for the 8-week study period. Study 2: subjects given 400 mg BH(4) had decreased systolic (P=0.03) and mean BP (P=0.04), with a peak decline of 16+/-19 mm Hg (P=0.04) at 3 weeks. BP returned to baseline 4 weeks after discontinuation. Significant improvement in endothelial function was observed in Study 1 subjects and those receiving 400 mg BH(4). There was no significant change in subjects given the 200 mg dose. This pilot investigation indicates that oral BH(4) at a daily dose of 400 mg or higher has a significant and sustained antihypertensive effect in subjects with poorly controlled hypertension, an effect that is associated with improved endothelial NO bioavailability.

[Musculoskeletal biomechanics of the knee joint. Principles of preoperative planning for osteotomy and joint replacement]

The long-term clinical outcome of surgical interventions at the knee is dependent upon the quality of the restoration of normal function, together with moderate musculoskeletal loading conditions. In order to achieve this, it is essential to consider biomechanical knowledge during the planning and execution of the procedures. Until now, such knowledge has only been available in books and journal manuscripts and is merely considered during preoperative planning. Its transfer into the specific intraoperative situation is, however, primarily dependent upon the surgeon's skills and understanding. Mathematical models hold the potential to provide the surgeon with detailed, patient-specific information on the in vivo forces, as well as their spatial and temporal distribution. Their application in clinical routine, however, requires a comprehensive validation. Based on a model validated against patient data, it has been shown that - mainly as a result of the action of the muscles - both the tibiofemoral as well as the patellofemoral joints experience substantial mechanical loads even during normal activities of daily living. The calculations further indicate that malalignment at the knee in the frontal plane of more than approximately 4 degrees results in considerably increased forces across the tibiofemoral joint. The actual change in force to a given degree of malalignment might, however, vary greatly between subjects. In order to additionally determine the distribution of the forces in more detail, a sufficiently accurate model of knee joint kinematics is required. In combination with MR-based in vivo imaging techniques, new mathematical models offer the possibility to capture the individual characteristics of knee kinematics and might additionally allow the effect of muscle activity on joint kinematics to be considered. By implementing these technologies in preoperative planning and navigation systems, up-to-date biomechanical knowledge can be made available at the surgeons' fingertips. We propose that optimizing the biomechanical conditions through using these approaches will allow the long-term function of the replaced joint to be significantly enhanced.

[Musculoskeletal load analysis. A biomechanical explanation for clinical results--and more?]

Mechanical loading of the lower extremities due to muscle and joint contact forces plays an important role in orthopaedic and trauma surgery. Detailed, patient specific information on the in vivo forces and their distribution is, however, currently not readily available to the surgeon in clinical routine. The goal of this study was to elucidate the relationship between the position of the cup and the musculoskeletal loading conditions at the hip using validated analyses, and further, to evaluate the predictions of the biomechanical conditions against the results of a clinical study. The results indicate that restoring the anatomical hip centre to its anatomical mediolateral position could help to reduce joint loads and add to the longevity of the reconstruction. The routine use of validated analyses of musculoskeletal loading conditions, such as in the presented example using standardised pre-operative planning and sound intra-operative decision support systems, could contribute to securing a high standard in patient treatment.

Structural and mechanistic implications of the amino acid sequence of calcium-transporting ATPases

Work is reviewed in which the amino acid sequences of two Ca2+-transporting ATPases of sarcoplasmic reticulum (SR) from slow (or cardiac) and fast skeletal muscle were determined from the nucleotide sequences of cloned cDNAs. Analysis of hydrophobicity and secondary structure, combined with the known shape derived from electron micrographs, leads to a model of five domains with functional implications. The major globular part of the molecule is in the cytoplasm and consists of one antiparallel and two parallel beta-sheet domains. One of the latter binds ATP, which, in the presence of Ca2+, phosphorylates an aspartic acid on the other domain. It is proposed that subsequent kinase-like movements are transmitted to the SR membrane via a penta-helical, calcium-binding stalk. The Ca2+ is first trapped and then translocated via the ten helices which constitute the transmembrane (channel) region. The difference in requirements for counter ions between the Ca2+- and Na+/K+-ATPases can be explained in terms of differing charge distributions in this channel.

Role of p38 mitogen-activated protein kinase in antiphospholipid antibody-mediated thrombosis and endothelial cell activation

BACKGROUND

The purpose of this study was to examine whether SB 203580, a p38 mitogen-activated protein kinase (MAPK) inhibitor, is effective in reversing the pathogenic effects of antiphospholipid antibodies.

METHODS

The adhesion of THP-1 monocytes to cultured endothelial cells (EC) treated with immunoglobulin G (IgG) from a patient with antiphospholipid syndrome (IgG-APS) or control IgG (IgG-NHS) in the presence and absence of SB 203580 was examined. The size of an induced thrombus in the femoral vein, the adhesion of leukocytes to EC of cremaster muscle, tissue factor (TF) activity in carotid artery and in peritoneal macrophages, the ex vivo expression of vascular cell adhesion molecule-1 (VCAM-1) in aorta preparations and platelet aggregation were studied in mice injected with IgG-APS or control IgG-NHS and with or without SB 203580.

RESULTS

SB 203580 significantly reduced the increased adhesion of THP-1 to EC in vitro, the number of leukocytes adhering to EC, the thrombus size, the TF activity in carotid arteries and in peritoneal mononuclear cells, and the expression of VCAM-1 in aorta of mice, and completely abrogated platelet aggregation induced by IgG-APS.

CONCLUSION

These data suggest that targeting the p38 MAPK pathway may be valuable in designing new therapy modalities for treating thrombosis in patients with APS.

Expression of cathepsin K is regulated by shear stress in cultured endothelial cells and is increased in endothelium in human atherosclerosis

Cathepsins, the lysosomal cysteine proteases, are involved in vascular remodeling and atherosclerosis. Genetic knockout of cathepsins S and K in mice has shown to reduce atherosclerosis, although the molecular mechanisms remain unclear. Because atherosclerosis preferentially occurs in arteries exposed to disturbed flow conditions, we hypothesized that shear stress would regulate cathepsin K expression and activity in endothelial cells. Mouse aortic endothelial cells (MAEC) exposed to proatherogenic oscillatory shear (OS, ± 5 dyn/cm2for 1 day) showed significantly higher cathepsin K expression and activity than that of atheroprotective, unidirectional laminar shear stress (LS, 15 dyn/cm2for 1 day). Western blot and active-site labeling studies showed an active, mature form of cathepsin K in the conditioned medium of MAEC exposed to OS but not in that of LS. Functionally, MAEC exposed to OS significantly increased elastase and gelatinase activity above that of LS. The OS-dependent elastase and gelatinase activities were significantly reduced by knocking down cathepsin K with small-interfering (si) RNA, but not by a nonsilencing siRNA control, suggesting that cathepsin K is a shear-sensitive protease. In addition, immunohistochemical analysis of atherosclerotic human coronary arteries showed a positive correlation between the cathepsin K expression levels in endothelium and elastic lamina integrity. These findings suggest that cathepsin K is a mechanosensitive, extracellular matrix protease that, in turn, may be involved in arterial wall remodeling and atherosclerosis.