Population pharmacokinetics of primaquine and its metabolites in African males

BACKGROUND

Primaquine (PQ) is the prototype 8-aminoquinoline drug, a class which targets gametocytes and hypnozoites. The World Health Organization (WHO) recommends adding a single low dose of primaquine to the standard artemisinin-based combination therapy (ACT) in order to block malaria transmission in regions with low malaria transmission. However, the haemolytic toxicity is a major adverse outcome of primaquine in glucose-6-phosphate dehydrogenase (G6PD)-deficient subjects. This study aimed to characterize the pharmacokinetic properties of primaquine and its major metabolites in G6PD-deficient subjects.

METHODS

A single low-dose of primaquine (0.4-0.5 mg/kg) was administered in twenty-eight African males. Venous and capillary plasma were sampled up to 24 h after the drug administration. Haemoglobin levels were observed up to 28 days after drug administration. Only PQ, carboxy-primaquine (CPQ), and primaquine carbamoyl-glucuronide (PQCG) were present in plasma samples and measured using liquid chromatography mass spectrometry. Drug and metabolites' pharmacokinetic properties were investigated using nonlinear mixed-effects modelling.

RESULTS

Population pharmacokinetic properties of PQ, CPQ, and PQCG can be described by one-compartment disposition kinetics with a transit-absorption model. Body weight was implemented as an allometric function on the clearance and volume parameters for all compounds. None of the covariates significantly affected the pharmacokinetic parameters. No significant correlations were detected between the exposures of the measured compounds and the change in haemoglobin or methaemoglobin levels. There was no significant haemoglobin drop in the G6PD-deficient patients after administration of a single low dose of PQ.

CONCLUSIONS

A single low-dose of PQ was haematologically safe in this population of G6PD-normal and G6PD-deficient African males without malaria. Trial registration NCT02535767.

Advancing the use of Long-Acting Extended Delivery formulations for HIV prevention in sub-Saharan Africa: challenges, opportunities, and recommendations

INTRODUCTION

The burden of HIV in sub-Saharan Africa (SSA) remains unacceptably high, and disproportionately affects girls and women. While the introduction of oral HIV pre-exposure prophylaxis (PrEP) in 2012 revolutionized HIV prevention, its effectiveness is dependent on user adherence and its implementation in SSA has faced numerous challenges. Patient-level, interpersonal and structural barriers, including, for example, daily pill burden, side effects, lack of partner support, testing and disclosure, and costs have been found to reduce adherence to oral PrEP.

DISCUSSION

Long-acting extended delivery (LAED) formulations for PrEP, such as injectable long-acting cabotegravir (CAB-LA) and dapivirine vaginal ring (DPV-VR) are critical additions to the HIV prevention toolkit and are especially important for populations such as adolescent girls and young women (AGYW) and other key populations who remain at significant risk of HIV acquisition while facing substantial barriers to preventive services. These LAED formulations have been shown to result in better adherence and fewer side effects, with CAB-LA being superior to oral PrEP in reducing the risk of HIV acquisition. They can be used to overcome user burden and adherence challenges. However, the successful rollout of the DPV-VR and CAB-LA may be hampered by issues such as a shortage of healthcare providers (HCPs), inadequate parenteral medication infrastructure, increased workload for HCPs, patient concerns, the price of the medications and the possibility of drug resistance.

CONCLUSIONS

SSA must develop laboratory capabilities for monitoring patients on LAED formulations and enhance research on developing more non-injectable LAED formulations. There is a need to train and retain more HCPs, implement task shifting, invest in healthcare infrastructure and integrate healthcare services. To reduce costs and improve availability, the region must advocate for patent license waivers for LAED formulations and procure drugs collectively as a region.

Clinical features and overall survival of osteosarcoma of the mandible

Osteosarcoma is the most common bone sarcoma and is typically found in the distal femur, proximal tibia, and proximal humerus. While several factors are known to influence survival, less is known regarding the influence of primary tumor location. This study describes the clinical features and prognosis of mandibular osteosarcoma. The SEER database was utilized to identify cases of mandibular osteosarcoma diagnosed between 2004 and 2015. Sex, age, grade, histological subtype, tumor size, tumor extension, presence of metastasis at diagnosis, and therapeutic intervention were determined. Osteosarcomas originating from other sites were assessed for comparison. There were 164 cases of mandibular osteosarcoma identified, representing 5.5% of all surveyed osteosarcomas. The 2-, 5-, and 10-year overall survival rates were 79.9%, 65.6% and 58.5%, respectively. Survival was worse for patients with older age, larger tumor size, metastatic disease, and absence of surgical resection. Compared to other sites, mandibular osteosarcomas were significantly smaller tumors and were far less likely to metastasize. Mandibular osteosarcoma manifested at an older age than the more common extremity osteosarcomas and presented with smaller tumors. Rates of metastasis of jaw osteosarcoma were much lower than osteosarcoma found in the extremities, while mortality rates were comparable.

Preventing HIV and achieving pregnancy among HIV sero-different couples: Pilot study of a safer conception intervention in Zimbabwe

Safer conception services are needed to minimize HIV transmission among HIV sero-different couples desiring pregnancy. Few studies have evaluated the choices couples make when offered multiple safer conception methods or real-world method acceptability and effectiveness. We piloted a comprehensive safer conception program (Clintrials.gov identifier: NCT03049176) for HIV sero-different couples planning pregnancy in Zimbabwe to measure feasibility, method uptake, acceptability, pregnancy outcome, and HIV transmission. This study was not designed to compare rates of HIV transmission by safer conception method choice but rather to understand choices couples make when seeking to minimize risk of HIV transmission and maximize likelihood of pregnancy. Couples in this prospective, non-randomized study were given a choice of one or more currently available safer conception methods: antiretroviral therapy (ART) with monthly viral load (VL) monitoring for the HIV-positive partner (ART/VL), pre-exposure prophylaxis (PrEP) for the HIV-negative partner, vaginal insemination (VI) for couples with an HIV-positive woman, and semen washing (SW) for couples with an HIV-positive man. Couples were followed monthly for up to 12 months of pregnancy attempts, quarterly during pregnancy, and 12 weeks post-partum. At each visit, data on method use, urine for pregnancy testing, and blood for HIV antibody testing, or viral load if HIV-positive, were obtained. Infants born to HIV-positive women were tested for HIV at 6 and 12 weeks. Between March 2017 and June 2019, 46 individuals from 23 HIV sero-different partnerships were enrolled and followed. At enrollment, all couples chose ART/VL, and all couples chose at least one additional method; 74% chose PrEP, 36% chose SW, and 25% chose VI. During pre-pregnancy follow-up visits, three couples discontinued SW, and one couple discontinued VI; all four of these couples opted for ART/VL plus PrEP. Satisfaction with safer conception methods was high among those who chose ART/VL and PrEP. Twelve couples achieved pregnancy. There were no cases of HIV transmission to partners, and no infants tested positive for HIV. This safer conception program is feasible and acceptable, allowing sero-different couples to safely achieve pregnancy. Sero-different couples in Zimbabwe seek a combination of HIV prevention methods, particularly ART/VL plus PrEP. Trial Registration: Clintrials.gov, NCT03049176.

A quantitative evaluation of aerosol generation during awake tracheal intubation

Aerosol-generating procedures are medical interventions considered high risk for transmission of airborne pathogens. Tracheal intubation of anaesthetised patients is not high risk for aerosol generation; however, patients often perform respiratory manoeuvres during awake tracheal intubation which may generate aerosol. To assess the risk, we undertook aerosol monitoring during a series of awake tracheal intubations and nasendoscopies in healthy participants. Sampling was undertaken within an ultraclean operating theatre. Procedures were performed and received by 12 anaesthetic trainees. The upper airway was topically anaesthetised with lidocaine and participants were not sedated. An optical particle sizer continuously sampled aerosol. Passage of the bronchoscope through the vocal cords generated similar peak median (IQR [range]) aerosol concentrations to coughing, 1020 (645-1245 [120-48,948]) vs. 1460 (390-2506 [40-12,280]) particles.l^-1 respectively, p = 0.266. Coughs evoked when lidocaine was sprayed on the vocal cords generated 91,700 (41,907-166,774 [390-557,817]) particles.l^-1 which was significantly greater than volitional coughs (p < 0.001). For 38 nasendoscopies in 12 participants, the aerosol concentrations were relatively low, 180 (120-525 [0-9552]) particles.l^-1 , however, five nasendoscopies generated peak aerosol concentrations greater than a volitional cough. Awake tracheal intubation and nasendoscopy can generate high concentrations of respiratory aerosol. Specific risks are associated with lidocaine spray of the larynx, instrumentation of the vocal cords, procedural coughing and deep breaths. Given the proximity of practitioners to patient-generated aerosol, airborne infection control precautions are appropriate when undertaking awake upper airway endoscopy (including awake tracheal intubation, nasendoscopy and bronchoscopy) if respirable pathogens cannot be confidently excluded.

Safety of single-dose primaquine as a Plasmodium falciparum gametocytocide: a systematic review and meta-analysis of individual patient data

BACKGROUND

In 2012, the World Health Organization (WHO) recommended single low-dose (SLD, 0.25 mg/kg) primaquine to be added as a Plasmodium (P.) falciparum gametocytocide to artemisinin-based combination therapy (ACT) without glucose-6-phosphate dehydrogenase (G6PD) testing, to accelerate malaria elimination efforts and avoid the spread of artemisinin resistance. Uptake of this recommendation has been relatively slow primarily due to safety concerns.

METHODS

A systematic review and individual patient data (IPD) meta-analysis of single-dose (SD) primaquine studies for P. falciparum malaria were performed. Absolute and fractional changes in haemoglobin concentration within a week and adverse effects within 28 days of treatment initiation were characterised and compared between primaquine and no primaquine arms using random intercept models.

RESULTS

Data comprised 20 studies that enrolled 6406 participants, of whom 5129 (80.1%) had received a single target dose of primaquine ranging between 0.0625 and 0.75 mg/kg. There was no effect of primaquine in G6PD-normal participants on haemoglobin concentrations. However, among 194 G6PD-deficient African participants, a 0.25 mg/kg primaquine target dose resulted in an additional 0.53 g/dL (95% CI 0.17-0.89) reduction in haemoglobin concentration by day 7, with a 0.27 (95% CI 0.19-0.34) g/dL haemoglobin drop estimated for every 0.1 mg/kg increase in primaquine dose. Baseline haemoglobin, young age, and hyperparasitaemia were the main determinants of becoming anaemic (Hb < 10 g/dL), with the nadir observed on ACT day 2 or 3, regardless of G6PD status and exposure to primaquine. Time to recovery from anaemia took longer in young children and those with baseline anaemia or hyperparasitaemia. Serious adverse haematological events after primaquine were few (9/3, 113, 0.3%) and transitory. One blood transfusion was reported in the primaquine arms, and there were no primaquine-related deaths. In controlled studies, the proportions with either haematological or any serious adverse event were similar between primaquine and no primaquine arms.

CONCLUSIONS

Our results support the WHO recommendation to use 0.25 mg/kg of primaquine as a P. falciparum gametocytocide, including in G6PD-deficient individuals. Although primaquine is associated with a transient reduction in haemoglobin levels in G6PD-deficient individuals, haemoglobin levels at clinical presentation are the major determinants of anaemia in these patients.

TRIAL REGISTRATION

PROSPERO, CRD42019128185.

Quantitative evaluation of aerosol generation from upper airway suctioning assessed during tracheal intubation and extubation sequences in anaesthetized patients

BACKGROUND

Open respiratory suctioning is defined as an aerosol generating procedure (AGP). Laryngopharyngeal suctioning, used to clear secretions during anaesthesia, is widely managed as an AGP. However, it is uncertain whether upper airway suctioning should be designated as an AGP due to the lack of both aerosol and epidemiological evidence.

AIM

To assess the relative risk of aerosol generation by upper airway suctioning during tracheal intubation and extubation in anaesthetized patients.

METHODS

This prospective environmental monitoring study was undertaken in an ultraclean operating theatre setting to assay aerosol concentrations during intubation and extubation sequences, including upper airway suctioning, for patients undergoing surgery (N=19). An optical particle sizer (particle size 0.3-10 μm) sampled aerosol 20 cm above the patient's mouth. Baseline recordings (background, tidal breathing and volitional coughs) were followed by intravenous induction of anaesthesia with neuromuscular blockade. Four periods of laryngopharyngeal suctioning were performed with a Yankauer sucker: pre-laryngoscopy, post-intubation, pre-extubation and post-extubation.

FINDINGS

Aerosol was reliably detected {median 65 [interquartile range (IQR) 39-259] particles/L} above background [median 4.8 (IQR 1-7) particles/L, P<0.0001] when sampling in close proximity to the patient's mouth during tidal breathing. Upper airway suctioning was associated with a much lower average aerosol concentration than breathing [median 6.0 (IQR 0-12) particles/L, P=0.0007], and was indistinguishable from background (P>0.99). Peak aerosol concentrations recorded during suctioning [median 45 (IQR 30-75) particles/L] were much lower than during volitional coughs [median 1520 (IQR 600-4363) particles/L, P<0.0001] and tidal breathing [median 540 (IQR 300-1826) particles/L, P<0.0001].

CONCLUSION

Upper airway suctioning during airway management was not associated with a higher aerosol concentration compared with background, and was associated with a much lower aerosol concentration compared with breathing and coughing. Upper airway suctioning should not be designated as a high-risk AGP.

Mechanistic Modelling of Primaquine Pharmacokinetics, Gametocytocidal Activity, and Mosquito Infectivity

Clinical studies have shown that adding a single 0.25mg base/kg dose of primaquine to standard antimalarial regimens rapidly sterilises Plasmodium falciparum gametocytes. However, the mechanism of action and overall impact on malaria transmission is still unknown. Using data from 81 adult Malians with P. falciparum gametocytaemia who received the standard dihydroartemisinin-piperaquine treatment course and were randomised to receive either a single dose of primaquine between 0.0625 and 0.5 mg base/kg or placebo. We characterised the pharmacokinetic-pharmacodynamic relationships for transmission blocking activity. Both gametocyte clearance and mosquito infectivity were assessed. A mechanistically-linked pharmacokinetic-pharmacodynamic model adequately described primaquine and carboxy-primaquine pharmacokinetics, gametocyte dynamics, and mosquito infectivity at different clinical doses of primaquine. Primaquine showed a dose-dependent gametocytocidal effect that precedes clearance. A single low dose of primaquine (0.25 mg/kg) rapidly prevented P. falciparum transmissibility.

A quantitative evaluation of aerosol generation during supraglottic airway insertion and removal

Many guidelines consider supraglottic airway use to be an aerosol-generating procedure. This status requires increased levels of personal protective equipment, fallow time between cases and results in reduced operating theatre efficiency. Aerosol generation has never been quantitated during supraglottic airway use. To address this evidence gap, we conducted real-time aerosol monitoring (0.3-10-µm diameter) in ultraclean operating theatres during supraglottic airway insertion and removal. This showed very low background particle concentrations (median (IQR [range]) 1.6 (0-3.1 [0-4.0]) particles.l-1 ) against which the patient's tidal breathing produced a higher concentration of aerosol (4.0 (1.3-11.0 [0-44]) particles.l-1 , p = 0.048). The average aerosol concentration detected during supraglottic airway insertion (1.3 (1.0-4.2 [0-6.2]) particles.l-1 , n = 11), and removal (2.1 (0-17.5 [0-26.2]) particles.l-1 , n = 12) was no different to tidal breathing (p = 0.31 and p = 0.84, respectively). Comparison of supraglottic airway insertion and removal with a volitional cough (104 (66-169 [33-326]), n = 27), demonstrated that supraglottic airway insertion/removal sequences produced <4% of the aerosol compared with a single cough (p < 0.001). A transient aerosol increase was recorded during one complicated supraglottic airway insertion (which initially failed to provide a patent airway). Detailed analysis of this event showed an atypical particle size distribution and we subsequently identified multiple sources of non-respiratory aerosols that may be produced during airway management and can be considered as artefacts. These findings demonstrate supraglottic airway insertion/removal generates no more bio-aerosol than breathing and far less than a cough. This should inform the design of infection prevention strategies for anaesthetists and operating theatre staff caring for patients managed with supraglottic airways.

Novel use of social media to assess and improve coastal flood forecasts and hazard alerts

Coastal communities and infrastructure need protection from flooding and wave overtopping events. Assessment of hazard prediction methods, used in sea defence design, defence performance inspections and forecasting services, requires observations at the land-sea interface but these are rarely collected. Here we show how a database of hindcast overtopping events, and the conditions that cause them, can be built using qualitative overtopping information obtained from social media. We develop a database for a case study site at Crosby in the Northwest of England, use it to test the standard methods applied in operational flood forecasting services and new defence design, and suggest improvements to these methods. This novel approach will become increasingly important to deliver long-term, cost-effective coastal management solutions as sea-levels rise and coastal populations grow. At sites with limited, or no, monitoring or forecasting services, this approach, especially if combined with citizen science initiatives, could underpin the development of simplified early warning systems.

Systematic review of the use of translated patient-reported outcome measures in cancer trials

BACKGROUND

Patient-reported outcomes (PROs) are used in clinical trials to assess the effectiveness and tolerability of interventions. Inclusion of participants from different ethnic backgrounds is essential for generalisability of cancer trial results. PRO data collection should include appropriately translated patient-reported outcome measures (PROMs) to minimise missing data and sample attrition.

METHODS

Protocols and/or publications from cancer clinical trials using a PRO endpoint and registered on the National Institute for Health Research Portfolio were systematically reviewed for information on recruitment, inclusion of ethnicity data, and use of appropriately translated PROMs. Semi-structured interviews were conducted with key stakeholders to explore barriers and facilitators for optimal PRO trial design, diverse recruitment and reporting, and use of appropriately translated PROMs.

RESULTS

Eighty-four trials met the inclusion criteria, only 14 (17%) (n = 4754) reported ethnic group data, and ethnic group recruitment was low, 611 (13%). Although 8 (57%) studies were multi-centred and multi-national, none reported using translated PROMs, although available for 7 (88%) of the studies. Interviews with 44 international stakeholders identified a number of perceived barriers to ethnically diverse recruitment including diverse participant engagement, relevance of ethnicity to research question, prominence of PROs, and need to minimise investigator burden. Stakeholders had differing opinions on the use of translated PROMs, the impact of trial designs, and recruitment strategies on diverse recruitment. Facilitators of inclusive research were described and examples of good practice identified.

CONCLUSIONS

Greater transparency is required when PROs are used as primary or secondary outcomes in clinical trials. Protocols and publications should demonstrate that recruitment was accessible to diverse populations and facilitated by trial design, recruitment strategies, and appropriate PROM usage. The use of translated PROMs should be made explicit when used in cancer clinical trials.

Trial of remote continuous versus intermittent NEWS monitoring after major surgery (TRaCINg): a feasibility randomised controlled trial

BACKGROUND

Despite medical advances, major surgery remains high risk with up to 44% of patients experiencing postoperative complications. Early recognition of postoperative complications is crucial in reducing morbidity and preventing long-term disability. The current standard of care is intermittent manual vital signs monitoring, but new wearable remote monitors offer the benefits of continuous vital signs monitoring without limiting the patient's mobility. The aim of this study was to evaluate the feasibility, acceptability and clinical outcomes of continuous remote monitoring after major surgery.

METHODS

The study was a randomised, controlled, unblinded, parallel group, feasibility trial. Adult patients undergoing elective major surgery were randomly assigned to receive continuous remote monitoring and normal National Early Warning Score (NEWS) monitoring (intervention group) or normal NEWS monitoring alone (control group). Continuous remote monitoring was achieved using the SensiumVitals® wireless patch which is worn on the patient's chest and monitors heart rate, respiratory rate and temperature continuously, and alerts the nurse when there is deviation from pre-set physiological norms. Feasibility was assessed by evaluating recruitment rate, adherence to protocol and randomisation and the amount of missing data. Clinical outcomes included time to antibiotics in cases of sepsis, length of hospital stay, number of critical care admissions and rate of hospital readmission within 30 days of discharge.

RESULTS

One hundred and thirty-six patients were randomised between October 2018 and April 2019: 67 to the control group and 69 to the intervention group. Recruitment was completed prior to the 12 month target with a high rate of eligibility and consent. Missing data was limited only to questionnaire responses; no participants were lost to follow-up and only one participant was withdrawn due to loss of capacity. The number of patients classed as 'drop-out' due to design (8.1%) were less than anticipated, and there were no participants who crossed over into the alternative trial allocation group. Seventeen participants in the intervention group (28%) did not adhere to the monitoring protocol. No formal comparisons between arms was undertaken; however, participants had fewer unplanned critical care admissions (1 versus 5) and had a shorter average length of hospital stay (11.6 days (95% confidence interval 9.5-13.7 days) versus 16.2 days (95% confidence interval 11.3-21.2 days)) in the continuous vital signs monitoring group. The time taken to receive antibiotics in cases of sepsis was similar in both arms. A cost-utility analysis indicated that the remote monitoring system was cost-saving when compared to standard NEWS monitoring alone.

CONCLUSIONS

It is feasible to perform a large-scale randomised controlled trial of continuous remote monitoring after major surgery. Progression to a definitive multicentre randomised controlled trial would be appropriate, taking consideration of factors, such as patient adherence, that might mask the potential benefit of additional monitoring.

TRIAL REGISTRATION

ISRCTN registry with study ID ISRCTN16601772 . Registered 30 August 2017.

Efficacy of Single-Dose Primaquine With Artemisinin Combination Therapy on Plasmodium falciparum Gametocytes and Transmission: An Individual Patient Meta-Analysis

BACKGROUND

Since the World Health Organization recommended single low-dose (0.25 mg/kg) primaquine (PQ) in combination with artemisinin-based combination therapies (ACTs) in areas of low transmission or artemisinin-resistant Plasmodium falciparum, several single-site studies have been conducted to assess efficacy.

METHODS

An individual patient meta-analysis to assess gametocytocidal and transmission-blocking efficacy of PQ in combination with different ACTs was conducted. Random effects logistic regression was used to quantify PQ effect on (1) gametocyte carriage in the first 2 weeks post treatment; and (2) the probability of infecting at least 1 mosquito or of a mosquito becoming infected.

RESULTS

In 2574 participants from 14 studies, PQ reduced PCR-determined gametocyte carriage on days 7 and 14, most apparently in patients presenting with gametocytemia on day 0 (odds ratio [OR], 0.22; 95% confidence interval [CI], .17-.28 and OR, 0.12; 95% CI, .08-.16, respectively). Rate of decline in gametocyte carriage was faster when PQ was combined with artemether-lumefantrine (AL) compared to dihydroartemisinin-piperaquine (DP) (P = .010 for day 7). Addition of 0.25 mg/kg PQ was associated with near complete prevention of transmission to mosquitoes.

CONCLUSIONS

Transmission blocking is achieved with 0.25 mg/kg PQ. Gametocyte persistence and infectivity are lower when PQ is combined with AL compared to DP.

Correction to: Solochrome cyanine: A histological stain for cobalt-chromium wear particles in metal-on-metal periprosthetic tissues

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Solochrome cyanine: A histological stain for cobalt-chromium wear particles in metal-on-metal periprosthetic tissues

Metal-on-metal (MoM) hip arthroplasties produce abundant implant-derived wear debris composed mainly of cobalt (Co) and chromium (Cr). Cobalt-chromium (Co-Cr) wear particles are difficult to identify histologically and need to be distinguished from other wear particle types and endogenous components (e.g., haemosiderin, fibrin) which may be present in MoM periprosthetic tissues. In this study we sought to determine whether histological stains that have an affinity for metals are useful in identifying Co-Cr wear debris in MoM periprosthetic tissues. Histological sections of periprosthetic tissue from 30 failed MoM hip arthroplasties were stained with haematoxylin-eosin (HE), Solochrome Cyanine (SC), Solochrome Azurine (SA) and Perls' Prussian Blue (PB). Sections of periprosthetic tissue from 10 cases of non-MoM arthroplasties using other implant biomaterials, including titanium, ceramic, polymethylmethacrylate (PMMA) and ultra-high molecular weight polyethylene (UHMWP) were similarly analysed. Sections of 10 cases of haemosiderin-containing knee tenosynovial giant cell tumour (TSGCT) were also stained with HE, SC, SA and PB. In MoM periprosthetic tissues, SC stained metal debris in phagocytic macrophages and in the superficial necrotic zone which exhibited little or no trichrome staining for fibrin. In non-MoM periprosthetic tissues, UHMWP, PMMA, ceramic and titanium particles were not stained by SC. Prussian Blue, but not SC or SA, stained haemosiderin deposits in MoM periprosthetic tissues and TSGT. Our findings show that SC staining (most likely Cr-associated) is useful in distinguishing Co-Cr wear particles from other metal/non-metal wear particles types in histological preparations of periprosthetic tissue and that SC reliably distinguishes haemosiderin from Co-Cr wear debris.

Disseminating technology in global surgery

Background

Effective dissemination of technology in global surgery is vital to realize universal health coverage by 2030. Challenges include a lack of human resource, infrastructure and finance. Understanding these challenges, and exploring opportunities and solutions to overcome them, are essential to improve global surgical care.

Methods

This review focuses on technologies and medical devices aimed at improving surgical care and training in low- and middle-income countries. The key considerations in the development of new technologies are described, along with strategies for evaluation and wider dissemination. Notable examples of where the dissemination of a new surgical technology has achieved impact are included.

Results

Employing the principles of frugal and responsible innovation, and aligning evaluation and development to high scientific standards help overcome some of the challenges in disseminating technology in global surgery. Exemplars of effective dissemination include low-cost laparoscopes, gasless laparoscopic techniques and innovative training programmes for laparoscopic surgery; low-cost and versatile external fixation devices for fractures; the LifeBox pulse oximeter project; and the use of immersive technologies in simulation, training and surgical care delivery.

Conclusion

Core strategies to facilitate technology dissemination in global surgery include leveraging international funding, interdisciplinary collaboration involving all key stakeholders, and frugal scientific design, development and evaluation.

Trial of Remote Continuous versus Intermittent NEWS monitoring after major surgery (TRaCINg): protocol for a feasibility randomised controlled trial

Background

Despite medical advances, major surgery remains high risk. Up to 44% of patients experience postoperative complications, which can have huge impacts for patients and the healthcare system. Early recognition of postoperative complications is crucial in reducing morbidity and preventing long-term disability. The current standard of care is intermittent manual vital signs monitoring, but new wearable remote monitors offer the benefits of continuous vital signs monitoring without limiting the patient's mobility. The aim of this study is to evaluate the feasibility, acceptability and clinical impacts of continuous remote monitoring after major surgery.

Methods

The study is a randomised, controlled, unblinded, parallel group, feasibility trial. Adult patients undergoing elective major surgery will be invited to participate if they have the capacity to provided informed, written consent and do not have a cardiac pacemaker or an allergy to adhesives. Participants will be randomly assigned to receive continuous remote monitoring and normal National Early Warning Score (NEWS) monitoring (intervention group) or normal NEWS monitoring alone (control group). Continuous remote monitoring will be achieved using the SensiumVitals® wireless patch which is worn on the patient's chest and monitors heart rate, respiratory rate and temperature continuously and alerts the nurse when there is deviation from pre-set physiological norms. Participants will be followed up throughout their hospital admission and for 30 days after discharge. Feasibility will be assessed by evaluating recruitment rate, adherence to protocol and randomisation, and the amount of missing data. The acceptability of the patch to nursing staff and patients will be assessed using questionnaires and interviews. Clinical outcomes will include time to antibiotics in cases of sepsis, length of hospital stay, number of critical care admissions and rate of readmission within 30 days of discharge.

Discussion

Early detection and treatment of complications minimises the need for critical care, improves patient outcomes, and produces significant cost savings for the healthcare system. Remote continuous monitoring systems have the potential to allow earlier detection of complications, but evidence from the literature is mixed. Demonstrating significant benefit over intermittent monitoring to offset the practical and economic implications of continuous monitoring requires well-controlled studies in high-risk populations to demonstrate significant differences in clinical outcomes; this feasibility trial seeks to provide evidence of how best to conduct such a confirmatory trial.

Trial registration

This study is listed on the ISRCTN registry with study ID ISRCTN16601772.

Efficacy and safety of primaquine and methylene blue for prevention of Plasmodium falciparum transmission in Mali: a phase 2, single-blind, randomised controlled trial

BACKGROUND

Primaquine and methylene blue are gametocytocidal compounds that could prevent Plasmodium falciparum transmission to mosquitoes. We aimed to assess the efficacy and safety of primaquine and methylene blue in preventing human to mosquito transmission of P falciparum among glucose-6-phosphate dehydrogenase (G6PD)-normal, gametocytaemic male participants.

METHODS

This was a phase 2, single-blind, randomised controlled trial done at the Clinical Research Centre of the Malaria Research and Training Centre (MRTC) of the University of Bamako (Bamako, Mali). We enrolled male participants aged 5-50 years with asymptomatic P falciparum malaria. G6PD-normal participants with gametocytes detected by blood smear were randomised 1:1:1:1 in block sizes of eight, using a sealed-envelope design, to receive either sulfadoxine-pyrimethamine and amodiaquine, sulfadoxine-pyrimethamine and amodiaquine plus a single dose of 0·25 mg/kg primaquine, dihydroartemisinin-piperaquine, or dihydroartemisinin-piperaquine plus 15 mg/kg per day methylene blue for 3 days. Laboratory staff, investigators, and insectary technicians were masked to the treatment group and gametocyte density of study participants. The study pharmacist and treating physician were not masked. Participants could request unmasking. The primary efficacy endpoint, analysed in all infected patients with at least one infectivity measure before and after treatment, was median within-person percentage change in mosquito infectivity 2 and 7 days after treatment, assessed by membrane feeding. This study is registered with ClinicalTrials.gov, number NCT02831023.

FINDINGS

Between June 27, 2016, and Nov 1, 2016, 80 participants were enrolled and assigned to the sulfadoxine-pyrimethamine and amodiaquine (n=20), sulfadoxine-pyrimethamine and amodiaquine plus primaquine (n=20), dihydroartemisinin-piperaquine (n=20), or dihydroartemisinin-piperaquine plus methylene blue (n=20) groups. Among participants infectious at baseline (54 [68%] of 80), those in the sulfadoxine-pyrimethamine and amodiaquine plus primaquine group (n=19) had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with sulfadoxine-pyrimethamine and amodiaquine alone (n=12; -10·2%, IQR -143·9 to 56·6; p<0·0001). The dihydroartemisinin-piperaquine plus methylene blue (n=11) group had a median 100% (IQR 100 to 100) within-person reduction in mosquito infectivity on day 2, a larger reduction than was noted with dihydroartemisinin-piperaquine alone (n=12; -6·0%, IQR -126·1 to 86·9; p<0·0001). Haemoglobin changes were similar between gametocytocidal arms and their respective controls. After exclusion of blue urine, adverse events were similar across all groups (59 [74%] of 80 participants had 162 adverse events overall, 145 [90%] of which were mild).

INTERPRETATION

Adding a single dose of 0·25 mg/kg primaquine to sulfadoxine-pyrimethamine and amodiaquine or 3 days of 15 mg/kg per day methylene blue to dihydroartemisinin-piperaquine was highly efficacious for preventing P falciparum transmission. Both primaquine and methylene blue were well tolerated.

FUNDING

Bill & Melinda Gates Foundation, European Research Council.

What motivates serodiscordant couples to prevent HIV transmission within their relationships: findings from a PrEP implementation study in Kenya

With the planned scale-up of pre-exposure prophylaxis (PrEP) for HIV prevention among serodiscordant couples in resource-limited settings, gaining an understanding of what motivates serodiscordant couples to prevent HIV is critical. We conducted 44 semi-structured, in-depth individual or couple interviews with 63 participants (33 HIV-infected and 30 HIV-uninfected participants) enrolled in a prospective implementation study of oral antiretroviral-based prevention in Kisumu, Kenya. Transcripts were iteratively analysed using inductive content analysis. Findings point to the importance of maintaining the emotional and economic stability of the partnership and family as motivators in preventing HIV transmission. Female participants identified fear of blame or potential violence for transmitting HIV as a motivator. Furthermore, couples primarily held the HIV-infected individual responsible for HIV prevention, but also held women more accountable for the use of prevention methods such as condoms. These themes substantiate traditional gender norms but also reveal how dyadic interdependence challenges these norms. As programmes in resource-limited settings scale up PrEP access, they should simultaneously capitalise on HIV serodiscordant couples' motivations for HIV prevention and address gender norms so women do not find themselves unduly responsible for the prevention of HIV transmission.

The impact of continuous versus intermittent vital signs monitoring in hospitals: A systematic review and narrative synthesis

BACKGROUND

Continuous vital signs monitoring on general hospital wards may allow earlier detection of patient deterioration and improve patient outcomes. This systematic review will assess if continuous monitoring is practical outside of the critical care setting, and whether it confers any clinical benefit to patients.

METHODS

MEDLINE^®, MEDLINE^® In-Process, EMBASE, CINAHL and The Cochrane Library were searched for articles that evaluated the clinical or non-clinical outcomes of continuous vital signs monitoring in adults outside of the critical care setting. The protocol was registered with PROSPERO (CRD42017058098).

FINDINGS

Twenty-four studies met the inclusion criteria and reported outcomes on a total of 40,274 patients and 59 ward staff in nine countries. The majority of studies showed benefits in terms of critical care use and length of hospital stay. Larger studies were more likely to demonstrate clinical benefit, particularly critical care use and length of hospital stay. Three studies showed cost-effectiveness. Barriers to implementation included nursing and patient satisfaction and the burden of false alerts.

CONCLUSIONS

Continuous vital signs monitoring outside the critical care setting is feasible and may provide a benefit in terms of improved patient outcomes and cost efficiency. Large, well-controlled studies in high-risk populations are required to evaluate the clinical benefit of continuous monitoring systems.

Patient attitudes towards remote continuous vital signs monitoring on general surgery wards: An interview study

BACKGROUND

Vital signs monitoring is used to identify deteriorating patients in hospital. The most common tool for vital signs monitoring is an early warning score, although emerging technologies allow for remote, continuous patient monitoring. A number of reviews have examined the impact of continuous monitoring on patient outcomes, but little is known about the patient experience. This study aims to discover what patients think of monitoring in hospital, with a particular emphasis on intermittent early warning scores versus remote continuous monitoring, in order to inform future implementations of continuous monitoring technology.

METHODS

Semi-structured interviews were undertaken with 12 surgical inpatients as part of a study testing a remote continuous monitoring device. All patients were monitored with both an early warning score and the new device. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis.

FINDINGS

Patients can see the value in remote, continuous monitoring, particularly overnight. However, patients appreciate the face-to-face aspect of early warning score monitoring as it allows for reassurance, social interaction, and gives them further opportunity to ask questions about their medical care.

CONCLUSION

Early warning score systems are widely used to facilitate detection of the deteriorating patient. Continuous monitoring technologies may provide added reassurance. However, patients value personal contact with their healthcare professionals and remote monitoring should not replace this. We suggest that remote monitoring is best introduced in a phased manner, and initially as an adjunct to usual care, with careful consideration of the patient experience throughout.

Acute intravenous exposure to silver nanoparticles during pregnancy induces particle size and vehicle dependent changes in vascular tissue contractility in Sprague Dawley rats

The use of silver nanoparticles (AgNP) raises safety concerns during susceptible life stages such as pregnancy. We hypothesized that acute intravenous exposure to AgNP during late stages of pregnancy will increase vascular tissue contractility, potentially contributing to alterations in fetal growth. Sprague Dawley rats were exposed to a single dose of PVP or Citrate stabilized 20 or 110nm AgNP (700μg/kg). Differential vascular responses and EC50 values were observed in myographic studies in uterine, mesenteric arteries and thoracic aortic segments, 24h post-exposure. Reciprocal responses were observed in aortic and uterine vessels following PVP stabilized AgNP with an increased force of contraction in uterine artery and increased relaxation responses in aorta. Citrate stabilized AgNP exposure increased contractile force in both uterine and aortic vessels. Intravenous AgNP exposure during pregnancy displayed particle size and vehicle dependent moderate changes in vascular tissue contractility, potentially influencing fetal blood supply.

Water-carbon dioxide solid phase equilibria at pressures above 4 GPa

A solid phase in the mixed water-carbon dioxide system, previously identified as carbonic acid, was observed in the high-pressure diamond-anvil cell. The pressure-temperature paths of both its melting and peritectic curves were measured, beginning at 4.4 GPa and 165 °C (where it exists in a quadruple equilibrium, together with an aqueous fluid and the ices H₂O(VII) and CO₂(I)) and proceeding to higher pressures and temperatures. Single-crystal X-ray diffraction revealed a triclinic crystal with unit cell parameters (at 6.5 GPa and 20 °C) of a = 5.88 Å, b = 6.59 Å, c = 6.99 Å, α = 88.7°, β = 79.7°, and γ = 67.7°. Raman spectra exhibit a major line at ~1080 cm⁻¹ and lattice modes below 300 cm⁻¹.

Facilitators and Barriers of Antiretroviral Therapy Initiation among HIV Discordant Couples in Kenya: Qualitative Insights from a Pre-Exposure Prophylaxis Implementation Study

Introduction

The World Health Organization now recommends antiretroviral therapy (ART) initiation for all HIV-infected individuals regardless of CD4 cell count or disease status. Understanding the facilitators and barriers to initiation of and adherence to ART is essential to successful scale-up of “universal” ART.

Methods

To investigate facilitators and barriers to ART initiation, we conducted 44 in-depth individual or couple interviews with 63 participants (33 participants with HIV and 30 without HIV) already enrolled in a prospective implementation study of oral antiretroviral-based prevention in Kisumu, Kenya between August and September 2014. A semi-structured interview guided discussions on: 1) perceived advantages and disadvantages of ART; 2) reasons for accepting or declining ART initiation; and 3) influence of prevention of transmission to partner or infant influencing ART use. Transcripts from the interviews were iteratively analyzed using inductive content analysis.

Results

HIV-infected participants indicated that living a healthier life, preventing HIV transmission to others, and appearing “normal” or “healthy” again facilitated their initiation of ART. While appearing “normal” allowed these individuals to interact with their communities without stigmatization, they also perceived community opposition to their initiating ART, because appearing “normal” again prevented community members from easily identifying infected individuals in their community. Denial of diagnosis, disclosure stigma, perceived side-effects, and challenges in obtaining refills were additional barriers to ART initiation.

Conclusions

Community perceptions play an important role in both facilitating and inhibiting ART initiation. Perceived stigma, including perceived community opposition to widespread ART use, is an important barrier to ART initiation. Addressing such barriers, while capitalizing on facilitators, to ART initiation should be central to universal ART scale-up efforts.

Primaquine to reduce transmission of Plasmodium falciparum malaria in Mali: a single-blind, dose-ranging, adaptive randomised phase 2 trial

BACKGROUND

Single low doses of primaquine, when added to artemisinin-based combination therapy, might prevent transmission of Plasmodium falciparum malaria to mosquitoes. We aimed to establish the activity and safety of four low doses of primaquine combined with dihydroartemisinin-piperaquine in male patients in Mali.

METHODS

In this phase 2, single-blind, dose-ranging, adaptive randomised trial, we enrolled boys and men with uncomplicated P falciparum malaria at the Malaria Research and Training Centre (MRTC) field site in Ouelessebougou, Mali. All participants were confirmed positive carriers of gametocytes through microscopy and had normal function of glucose-6-phosphate dehydrogenase (G6PD) on colorimetric quantification. In the first phase, participants were randomly assigned (1:1:1) to one of three primaquine doses: 0 mg/kg (control), 0·125 mg/kg, and 0·5 mg/kg. Randomisation was done with a computer-generated randomisation list (in block sizes of six) and concealed with sealed, opaque envelopes. In the second phase, different participants were sequentially assigned (1:1) to 0·25 mg/kg primaquine or 0·0625 mg/kg primaquine. Primaquine tablets were dissolved into a solution and administered orally in a single dose. Participants were also given a 3 day course of dihydroartemisinin-piperaquine, administered by weight (320 mg dihydroartemisinin and 40 mg piperaquine per tablet). Outcome assessors were masked to treatment allocation, but participants were permitted to find out group assignment. Infectivity was assessed through membrane-feeding assays, which were optimised through the beginning part of phase one. The primary efficacy endpoint was the mean within-person percentage change in mosquito infectivity 2 days after primaquine treatment in participants who completed the study after optimisation of the infectivity assay, had both a pre-treatment infectivity measurement and at least one follow-up infectivity measurement, and who were given the correct primaquine dose. The safety endpoint was the mean within-person change in haemoglobin concentration during 28 days of study follow-up in participants with at least one follow-up visit. This study is registered with ClinicalTrials.gov, number NCT01743820.

FINDINGS

Between Jan 2, 2013, and Nov 27, 2014, we enrolled 81 participants. In the primary analysis sample (n=71), participants in the 0·25 mg/kg primaquine dose group (n=15) and 0·5 mg/kg primaquine dose group (n=14) had significantly lower mean within-person reductions in infectivity at day 2-92·6% (95% CI 78·3-100; p=0·0014) for the 0·25 mg/kg group; and 75·0% (45·7-100; p=0·014) for the 0·5 mg/kg primaquine group-compared with those in the control group (n=14; 11·3% [-27·4 to 50·0]). Reductions were not significantly different from control for participants assigned to the 0·0625 mg/kg dose group (n=16; 41·9% [1·4-82·5]; p=0·16) and the 0·125 mg/kg dose group (n=12; 54·9% [13·4-96·3]; p=0·096). No clinically meaningful or statistically significant drops in haemoglobin were recorded in any individual in the haemoglobin analysis (n=70) during follow-up. No serious adverse events were reported and adverse events did not differ between treatment groups.

INTERPRETATION

A single dose of 0·25 mg/kg primaquine, given alongside dihydroartemisinin-piperaquine, was safe and efficacious for the prevention of P falciparum malaria transmission in boys and men who are not deficient in G6PD. Future studies should assess the safety of single-dose primaquine in G6PD-deficient individuals to define the therapeutic range of primaquine to enable the safe roll-out of community interventions with primaquine.

FUNDING

Bill & Melinda Gates Foundation.

Motivations for Intravaginal Product Use among a Cohort of Women in Los Angeles

OBJECTIVE

Intravaginal practices-including behaviors such as intravaginal cleansing and insertion of products-have been linked to a number of adverse reproductive health outcomes, including increased risk for bacterial vaginosis, sexually transmitted infections, and HIV. Currently, little is known about the motivations for intravaginal practices among women in the United States. The objective of this study was to identify and describe motivations for intravaginal washing and intravaginal insertion of products among women of differing ages and racial/ethnic groups.

METHODS

Between 2008 and 2010, we enrolled a convenience sample of sexually active women aged 18-65 years living in Los Angeles recruited through community education and outreach activities in HIV/AIDS service organizations, women's health clinics, community-based organizations, and HIV testing sites. At the enrollment visit, women completed a self-administered, computer-assisted questionnaire covering demographics, sexual behaviors, intravaginal practices, and motivations for intravaginal practices over the past month and past year.

RESULTS

We enrolled 141 women; 34% of participants were Caucasian, 40% African American, and 26% Latina. Peri-sexual intravaginal washing was common in all groups, whether to clean up after sex (70%) or to prepare for sex (54%). African American women were more likely to report learning to wash intravaginally from their mothers compared to Latina or Caucasian women (70% vs. 49%, P = 0.04). Sixty-one percent of African American women reported using a douching device over the past year compared to 41% of Latina and 40% of Caucasian women (p = 0.02). Younger women were more likely to report that their male partners wanted them to wash intravaginally than older women (77% vs. 24%, P<0.01), and more likely to report the removal of odors as a motive than older women (65% vs. 40%, P = 0.04). The most commonly used intravaginal products included sexual lubricants, petroleum jelly, body lotions, oils, and wet wipes. Use of these products varied by race, and motives given included increasing lubrication, preparing for sex, smelling good, and preventing sexually transmitted infections.

CONCLUSION

Women's intravaginal practices and motivations for these practices differ across race and age. Motivations for use also vary by type of intravaginal product used. Given that some intravaginal practices have been shown to be harmful, interventions, programs and counseling messages to encourage less harmful practices are needed, and should consider underlying motivations that influence women's vaginal practices. Practitioners may use these results to better support women in achieving vaginal health.

Carrier-wave shape effects in optical filamentation

Strong-field ionization in optical filaments created by ultrashort pulses with sub-cycle engineered waveforms is studied theoretically. To elucidate the physics of the recently demonstrated enhanced ionization yield and spatial control of the optical filament core in two color pulses, we employ two types of quantum models integrated into spatially resolved pulse-propagation simulations. We show that the dependence of the ionization on the shape of the excitation carrier is adiabatic in nature, and is driven by local temporal peaks of the electric field. Implications for the modeling of light-matter interactions in multicolor optical fields are also discussed.

Mass-like peripheral zone enhancement on CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer

PURPOSE

To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

MATERIALS AND METHODS

IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [n = 47]) or absent (n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted.

RESULTS

Scores of "5" were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8-15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98-0.99]; all 10 readers had specificity ≥95%). Attending scores of "5" were more predictive than resident scores of "5" (LR+: 14.7 [95% CI 5.8-37.2] vs. 7.6 [95% CI 4.2-13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98-1.00] vs. 0.97 [467/480, 95% CI 0.96-0.99]). Significant predictors of an assigned score of "5" included presence of a peripheral zone mass (p < 0.0001), larger size (p < 0.0001), and less reader experience (p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass (p = 0.0002) and larger size (p < 0.0001).

CONCLUSION

Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer.

Assessment of the metastable electronic state approach as a microscopically self-consistent description for the nonlinear response of atoms

This Letter presents the first quantitative assessment of the recently proposed metastable electronic state approach (MESA) for calculation of the nonlinear optical response of noble gas atoms. Based on the single active electron potentials for several atomic species, Stark resonant states are used to extract the nonlinear polarization and ionization rates free of any additional fitting parameters. It is shown that even the simplest version of the method provides a viable, first-principle-based, and self-consistent alternative to the standard model commonly used for simulations in the field of extreme nonlinear optics.

Cardiac Ischemia Reperfusion Injury Following Instillation of 20 nm Citrate-capped Nanosilver

BACKGROUND

Silver nanoparticles (AgNP) have garnered much interest due to their antimicrobial properties, becoming one of the most utilized nano-scale materials. However, any potential evocable cardiovascular injury associated with exposure has not been reported to date. We have previously demonstrated expansion of myocardial infarction after intratracheal (IT) instillation of carbon-based nanomaterials. We hypothesized pulmonary exposure to Ag core AgNP induces a measureable increase in circulating cytokines, expansion of cardiac ischemia-reperfusion (I/R) injury and is associated with depressed coronary constrictor and relaxation responses. Secondarily, we addressed the potential contribution of silver ion release on AgNP toxicity.

METHODS

Male Sprague-Dawley rats were exposed to 200 μl of 1 mg/ml of 20 nm citrate-capped Ag core AgNP, 0.01, 0.1, 1 mg/ml Silver Acetate (AgAc), or a citrate vehicle by intratracheal (IT) instillation. One and 7 days following IT instillation the lungs were evaluated for inflammation and the presence of silver; serum was analyzed for concentrations of selected cytokines; cardiac I/R injury and coronary artery reactivity were assessed.

RESULTS

AgNP instillation resulted in modest pulmonary inflammation with detection of silver in lung tissue and alveolar macrophages, elevation of serum cytokines: G-CSF, MIP-1α, IL-1β, IL-2, IL-6, IL-13, IL-10, IL-18, IL-17α, TNFα, and RANTES, expansion of I/R injury and depression of the coronary vessel reactivity at 1 day post IT compared to vehicle treated rats. Silver within lung tissue was persistent at 7 days post IT instillation and was associated with an elevation in cytokines: IL-2, IL-13, and TNFα and expansion of I/R injury. AgAc resulted in a concentration dependent infarct expansion and depressed vascular reactivity without marked pulmonary inflammation or serum cytokine response.

CONCLUSIONS

Based on these data, IT instillation of AgNP increases circulating levels of several key cytokines, which may contribute to persistent expansion of I/R injury possibly through an impaired vascular responsiveness.

Pattern of association between endemic Hawaiian fruit flies (Diptera, Tephritidae) and their symbiotic bacteria: Evidence of cospeciation events and proposal of "Candidatus Stammerula trupaneae"

Several insect lineages have evolved mutualistic association with symbiotic bacteria. This is the case of some species of mealybugs, whiteflies, weevils, tsetse flies, cockroaches, termites, carpenter ants, aphids and fruit flies. Some species of Tephritinae, the most specialized subfamily of fruit flies (Diptera: Tephritidae), harbour co-evolved vertically transmitted, bacterial symbionts in their midgut, known as "Candidatus Stammerula spp.". The 25 described endemic species of Hawaiian tephritids, plus at least three undescribed species, are taxonomically distributed among three genera: the cosmopolitan genus Trupanea (21 described spp.), the endemic genus Phaeogramma (2 spp.) and the Nearctic genus Neotephritis (2 spp.). We examined the presence of symbiotic bacteria in the endemic tephritids of the Hawaiian Islands, which represent a spectacular example of adaptive radiation, and tested the concordant evolution between host and symbiont phylogenies. We detected through PCR assays the presence of specific symbiotic bacteria, designated as "Candidatus Stammerula trupaneae", from 35 individuals of 15 species. The phylogeny of the insect host was reconstructed based on two regions of the mitochondrial DNA (16S rDNA and COI-tRNALeu-COII), while the bacterial 16S rRNA was used for the symbiont analysis. Host and symbiont phylogenies were then compared and evaluated for patterns of cophylogeny and strict cospeciation. Topological congruence between Hawaiian Tephritinae and their symbiotic bacteria phylogenies suggests a limited, but significant degree of host-symbiont cospeciation. We also explored the character reconstruction of three host traits, as island location, host lineage, and host tissue attacked, based on the symbiont phylogenies under the hypothesis of cospeciation.

The independent effect of living in malaria hotspots on future malaria infection: an observational study from Misungwi, Tanzania

BACKGROUND

As malaria transmission declines, continued improvements of prevention and control interventions will increasingly rely on accurate knowledge of risk factors and an ability to define high-risk areas and populations at risk for focal targeting of interventions. This paper explores the independent association between living in a hotspot and prospective risk of malaria infection.

METHODS

Malaria infection status defined by nPCR and AMA-1 status in year 1 were used to define geographic hotspots using two geospatial statistical methods (SaTScan and Kernel density smoothing). Other malaria risk factors for malaria infection were explored by fitting a multivariable model.

RESULTS

This study demonstrated that residing in infection hotspot of malaria transmission is an independent predictor of malaria infection in the future.

CONCLUSION

It is likely that targeting such hotspots with better coverage and improved malaria control strategies will result in more cost-efficient uses of resources to move towards malaria elimination.

Demonstration of the need for cardiovascular and pulmonary normative data for cancer survivors

Despite evidence that cancer and its treatments severely reduce cardiorespiratory fitness (CRF), normative data for cancer survivors do not exist. The present study identifies age and gender-specific CRF distributions in a cancer population. The use of cancer-specific normative CRF data may help stratify initial fitness status and assess improvements in response to exercise interventions in cancer survivors. Data from 703 cancer survivors were analyzed for this study. Quintiles were compiled for peak oxygen consumption (VO2peak), forced vital capacity (FVC), and forced expiratory volume (FEV1) for males and females in 5 age groups (19-39, 40-49, 50-59, 60-69, and ≥70 years of age). VO2peak values for the cancer population were significantly lower than the general US population. The cancer population average in each age group fell within the "very poor" classification of VO2peak values for the general population. FVC values in the cancer population were similar to the general population. Cancer survivors had very low age group-specific VO2peak values compared to the apparently healthy general US population. Previously, CRF values of cancer survivors were compared to normative values for the apparently healthy general population, which yielded imprecise classifications of initial fitness and changes in fitness, resulting in patient discouragement.

Vasculogenesis: a crucial player in the resistance of solid tumours to radiotherapy

Tumours have two main ways to develop a vasculature: by angiogenesis, the sprouting of endothelial cells from nearby blood vessels, and vasculogenesis, the formation of blood vessels from circulating cells. Because tumour irradiation abrogates local angiogenesis, the tumour must rely on the vasculogenesis pathway for regrowth after irradiation. Tumour irradiation produces a marked influx of CD11b(+) myeloid cells (macrophages) into the tumours, and these are crucial to the formation of blood vessels in the tumours after irradiation and for the recurrence of the tumours. This process is driven by increased tumour hypoxia, which increases levels of HIF-1 (hypoxia-inducible factor 1), which in turn upregulates SDF-1 (stromal cell-derived factor 1 or CXCL12), the main driver of the vasculogenesis pathway. Inhibition of HIF-1 or of its downstream target SDF-1 prevents the radiation-induced influx of the CD11b(+) myeloid cells and delays or prevents the tumours from recurring following irradiation. Others and we have shown that with a variety of tumours in both mice and rats, the inhibition of the SDF-1/CXCR4 pathway delays or prevents the recurrence of implanted or autochthonous tumours following irradiation or following treatment with vascular disrupting agents or some chemotherapeutic drugs such as paclitaxel. In addition to the recruited macrophages, endothelial progenitor cells (EPCs) are also recruited to the irradiated tumours, a process also driven by SDF-1. Together, the recruited proangiogenic macrophages and the EPCs reform the tumour vasculature and allow the tumour to regrow following irradiation. This is a new paradigm with major implications for the treatment of solid tumours by radiotherapy.

Vascular Tissue Contractility Changes Following Late Gestational Exposure to Multi-Walled Carbon Nanotubes or their Dispersing Vehicle in Sprague Dawley Rats

Multi-walled carbon nanotubes (MWCNTs) are increasingly used in industry and in nanomedicine raising safety concerns, especially during unique life-stages such as pregnancy. We hypothesized that MWCNT exposure during pregnancy will increase vascular tissue contractile responses by increasing Rho kinase signaling. Pregnant (17-19 gestational days) and non-pregnant Sprague Dawley rats were exposed to 100 μg/kg of MWCNTs by intratracheal instillation or intravenous administration. Vasoactive responses of uterine, mesenteric, aortic and umbilical vessels were studied 24 hours post-exposure by wire myography. The contractile responses of the vessel segments were different between the pregnant and non-pregnant rats, following MWCNT exposure. Maximum stress generation in the uterine artery segments from the pregnant rats following pulmonary MWCNT exposure was increased in response to angiotensin II by 4.9 mN/mm² (+118%), as compared to the naïve response and by 2.6 mN/mm² (+40.7%) as compared to the vehicle exposed group. Following MWCNT exposure, serotonin induced approximately 4 mN/mm² increase in stress generation of the mesenteric artery from both pregnant and non-pregnant rats as compared to the vehicle response. A significant contribution of the dispersion medium was identified as inducing changes in the contractile properties following both pulmonary and intravenous exposure to MWCNTs. Wire myographic studies in the presence of a Rho kinase inhibitor and RhoA and Rho kinase mRNA/protein expression of rat aortic endothelial cells were unaltered following exposure to MWCNTs, suggesting absent/minimal contribution of Rho kinase to the enhanced contractile responses following MWCNT exposure. The reactivity of the umbilical vein was not changed; however, mean fetal weight gain was reduced with dispersion media and MWCNT exposure by both routes. These results suggest a susceptibility of the vasculature during gestation to MWCNT and their dispersion media-induced vasoconstriction, predisposing reduced fetal growth during pregnancy.

Hot spot or not: a comparison of spatial statistical methods to predict prospective malaria infections

Background

Within affected communities, Plasmodium falciparum infections may be skewed in distribution such that single or small clusters of households consistently harbour a disproportionate number of infected individuals throughout the year. Identifying these hotspots of malaria transmission would permit targeting of interventions and a more rapid reduction in malaria burden across the whole community. This study set out to compare different statistical methods of hotspot detection (SaTScan, kernel smoothing, weighted local prevalence) using different indicators (PCR positivity, AMA-1 and MSP-1 antibodies) for prediction of infection the following year.

Methods

Two full surveys of four villages in Mwanza, Tanzania were completed over consecutive years, 2010-2011. In both surveys, infection was assessed using nested polymerase chain reaction (nPCR). In addition in 2010, serologic markers (AMA-1 and MSP-1₁₉ antibodies) of exposure were assessed. Baseline clustering of infection and serological markers were assessed using three geospatial methods: spatial scan statistics, kernel analysis and weighted local prevalence analysis. Methods were compared in their ability to predict infection in the second year of the study using random effects logistic regression models, and comparisons of the area under the receiver operating curve (AUC) for each model. Sensitivity analysis was conducted to explore the effect of varying radius size for the kernel and weighted local prevalence methods and maximum population size for the spatial scan statistic.

Results

Guided by AUC values, the kernel method and spatial scan statistics appeared to be more predictive of infection in the following year. Hotspots of PCR-detected infection and seropositivity to AMA-1 were predictive of subsequent infection. For the kernel method, a 1 km window was optimal. Similarly, allowing hotspots to contain up to 50% of the population was a better predictor of infection in the second year using spatial scan statistics than smaller maximum population sizes.

Conclusions

Clusters of AMA-1 seroprevalence or parasite prevalence that are predictive of infection a year later can be identified using geospatial models. Kernel smoothing using a 1 km window and spatial scan statistics both provided accurate prediction of future infection.

Inhibition of CXCR7 extends survival following irradiation of brain tumours in mice and rats

Background:

In experimental models of glioblastoma multiforme (GBM), irradiation (IR) induces local expression of the chemokine CXCL12/SDF-1, which promotes tumour recurrence. The role of CXCR7, the high-affinity receptor for CXCL12, in the tumour's response to IR has not been addressed.

Methods:

We tested CXCR7 inhibitors for their effects on tumour growth and/or animal survival post IR in three rodent GBM models. We used immunohistochemistry to determine where CXCR7 protein is expressed in the tumours and in human GBM samples. We used neurosphere formation assays with human GBM xenografts to determine whether CXCR7 is required for cancer stem cell (CSC) activity in vitro.

Results:

CXCR7 was detected on tumour cells and/or tumour-associated vasculature in the rodent models and in human GBM. In human GBM, CXCR7 expression increased with glioma grade and was spatially associated with CXCL12 and CXCL11/I-TAC. In the rodent GBM models, pharmacological inhibition of CXCR7 post IR caused tumour regression, blocked tumour recurrence, and/or substantially prolonged survival. CXCR7 expression levels on human GBM xenograft cells correlated with neurosphere-forming activity, and a CXCR7 inhibitor blocked sphere formation by sorted CSCs.

Conclusions:

These results indicate that CXCR7 inhibitors could block GBM tumour recurrence after IR, perhaps by interfering with CSCs.

CADASIL presenting with a behavioural variant frontotemporal dementia phenotype

The behavioural variant of frontotemporal dementia (bvFTD) is characterised by personality change with a decline in cognition. We describe two patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukencephalopathy (CADASIL) who presented with behavioural phenotypes similar to bvFTD. The first patient presented with progressive personality and behavioural change, had florid white matter hyperintensity, and had a novel missense mutation C366W in exon 7 of the Notch3 gene. The second patient presented with progressive memory impairment and marked personality changes after a transient ischaemic attack. In this second patient, the radiological features were subtle and only the family history of stroke prompted testing for CADASIL using Notch3 genotyping. We present these patients to demonstrate that CADASIL may mimic bvFTD, with little clinical or radiological evidence to distinguish the two. CADASIL may be an under-recognised diagnosis in apparent bvFTD. Screening Notch3 in a substantial and unselected cohort of frontotemporal dementia patients might be appropriate to investigate this possibility.