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Additional research across global health, ethics, methodology, and clinical medicine.

Publications (17)

Bromelain-based enzymatic debridement versus standard of care in deep partial- and full-thickness burns: A systematic review and meta-analysis of randomized controlled trials

Burns · Jul 2026 · Burn surgery; an affiliate's own clinical specialty, outside the research program

Federico Sacasa, Gustavo Herdocia Baus, Myiah P Quach, Robert E George, Michael L Bentz, Samuel O Poore, et al.

Abstract

Management of debridement-eligible thermal burns requires accurate removal of devitalized tissue. Tangential excision remains limited by imprecise depth assessment beneath opaque eschar, risking unintended dermal sacrifice. Bromelain-based enzymatic debridement (BBD) has emerged as an alternative; however, its impact on patient-level surgical outcomes has not been rigorously quantified in randomized trials. A systematic review and meta-analysis of randomized trials compared BBD with standard of care (SOC) in acute deep thermal burns. The primary outcome was the proportion requiring surgical excision. Random-effects models pooled effects. A prespecified sensitivity analysis evaluated a wound-level trial. Risk of bias was assessed using the Cochrane RoB 2 tool. Five randomized trials met criteria. Four reporting per-patient outcomes contributed to the primary meta-analysis (n = 336). BBD reduced surgical excision versus SOC (RR, 0.11; 95% CI, 0.06-0.23; I² = 0%), corresponding to an absolute risk reduction of 65% and a number needed to treat of 1.5. BBD was also associated with reduced autograft use, shorter time to debridement, and comparable or improved blinded scar assessments at 12 months. Open-label design was the principal source of potential bias. Sensitivity analysis including the wound-level trial preserved effect direction with increased heterogeneity. Randomized evidence demonstrates that, in early-treated debridement-eligible burns with limited total body surface area burned (TBSA), BBD reduces operative and graft burden without compromising wound closure or long-term remodeling. Future trials incorporating blinded operative endpoint adjudication, objective assessment of dermal preservation and broader clinical outcomes will further clarify treatment effect and optimize patient selection.

Local Nixtamalization Processes Reduce Aflatoxin B1 Concentration and Shift Metabolome in Naturally Contaminated Maize

J Agric Food Chem · Apr 2026

Hannah Glesener, Andrew M P Roberts, Haadia Tanveer, Darya Abdollahzadeh, Emeline Seegmiller, Blake Su, et al.

Abstract

Nixtamalization is an alkaline cooking process known to lower aflatoxin B1 (AFB1) in maize, yet reported efficacy varies (28-100% reduction). Thus, existing data are not sufficient to inform nixtamalization practices in specific local contexts. To investigate this, we conducted a controlled lab study using AFB1-contaminated Guatemalan maize to evaluate the effect of current rural Guatemalan cooking practices on the AFB1 concentration. We evaluated nine conditions varying calcium hydroxide concentration, steeping duration, maize washing, and tortilla-cooking parameters. Across all conditions, the AFB1 concentration decreased by 81%, with extended steeping achieving an 86% decrease. As expected, nixtamalization substantially increased calcium content (808.22%) with modest increases in iron, copper, and magnesium, while untargeted metabolomics identified processing-associated chemical changes and preliminary annotations to inform future targeted analysis. We demonstrate that incorporating local cooking practices into systematic laboratory evaluation provides useful food safety and nutrition data, offering a scalable model for household-level interventions in toxin-exposed populations worldwide.

X-ray Irradiation Reduces Live Aspergillus flavus Viability but Not Aflatoxin B1 in Naturally Contaminated Maize

Toxins (Basel) · Jul 2024

Hannah Glesener, Darya Abdollahzadeh, Christopher Muse, Rosa Krajmalnik-Brown, Mark A Weaver, Lee E Voth-Gaeddert

Abstract

Food crops around the world are commonly contaminated with Aspergillus flavus, which can produce the carcinogenic mycotoxin aflatoxin B1 (AFB1). The objective of this study is to test an X-ray irradiation sterilization method for studying AFB1 in contaminated maize samples in the laboratory. Maize that had been naturally contaminated with 300 ppb AFB1 by the growth of aflatoxigenic A. flavus was ground and then irradiated at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kGy. A. flavus was quantified by dilution plating on potato dextrose agar (PDA) and modified Rose Bengal media (MDRB) for viability and qPCR for gene presence. AFB1 was quantified by HPLC and ELISA. A. flavus viability, but not gene copies, significantly decreased with increasing doses of radiation (PDA: p < 0.001; MDRB: p < 0.001; qPCR: p = 0.026). AFB1 concentration did not significantly change with increasing doses of radiation (HPLC: p = 0.153; ELISA: p = 0.567). Our results imply that X-ray irradiation is an effective means of reducing viable A. flavus without affecting AFB1 concentrations. Reducing the hazard of fungal spores and halting AFB1 production at the targeted dose are important steps to safely and reproducibly move forward research on the global mycotoxin challenge.

Engaging the Guatemala Scientific Diaspora: The Power of Networking and Shared Learning

Front Res Metr Anal · Jun 2022

Kleinsy Bonilla, Claudia S Romero-Oliva, Susana Arrechea, Nereyda Y Ortiz Osejo, Sofia Mazariegos, Margarita Alonzo, et al.

Abstract

The underdevelopment of the higher education system in Guatemala and the fragility of its science and technology (S&T) contexts have compelled a significant number of talented Guatemalan scientists to be trained, educated, and employed abroad. The relocation of such skilled human power to different countries and regions has resulted in a growing Guatemalan Scientific Diaspora (GSD). Until recently, the emigration of scientists from the Global South to scientifically advanced countries in the North was studied as it negatively impacted the countries of origin. However, technological upgrades and globalization have progressively shifted the paradigm in which such scientific diasporas interact and connect, thus enabling them to influence their home countries positively. Due to the lack of knowledge-based evidence and functioning connecting platforms, the value and potential of the GSD in their involvement in proposing solutions to complex socio-economic, environmental, and other challenges faced by Guatemalan society remain unknown. Moreover, the lack of interaction of relevant stakeholders (S&T policy agents, international partners, higher education institutions and research centers, industry, and relevant not governmental organizations) represents a pervasive obstacle to the untapped impact of the GSD in the country. This study outlines the Guatemalan scientific diasporas' networking as a mechanism for building research excellence and intellectual capital. This force could respond to the need to strengthen the national science capacities and meet the demands for knowledge production and access to broader sectors of society. This research applied qualitative methodology that, through the conduction of focus group discussions and semi-structured interviews with members of the Guatemalan scientific community and relevant key stakeholders, delved into the existence and articulation of the GSD and potential stages for their engagement with their country of origin. Findings highlight the importance of digital and technological pathways that might leverage the GSD's knowledge and experience, channeling skills, and international connections for better interaction with the Guatemalan society. Furthermore, the discussion addresses how technology might turn brain drain into brain circulation, enabling the articulation of the GSD as a viable opportunity to generate collaboration between scientists abroad and local actors, ultimately impacting the building and development of Guatemalan science and national research capacities.

Efficacy of Mechanical Circulatory Support Used Before Versus After Primary Percutaneous Coronary Intervention in Patients with Cardiogenic Shock From ST-Elevation Myocardial Infarction: A Systematic Review and Meta-Analysis

Cardiovasc Revasc Med · May 2022

Gaspar Del Rio-Pertuz, Juthipong Benjanuwattra, Michel Juarez, Poemlarp Mekraksakit, Erwin Argueta-Sosa, Mohammad M Ansari

Abstract

Optimal timing to initiate mechanical circulatory support (MCS) in patients with ST-elevation myocardial infarction (STEMI) complicated by cardiogenic shock (CS) remains unclear with studies showing conflicting results on whether to start before or after primary percutaneous coronary intervention (PPCI). This study aims to examine the association between mortality and MCS initiated before vs after PPCI in patients with STEMI complicated by CS. We systematically searched PubMed, Embase, and Scopus for abstracts and full-text articles from inception to October 2021. Studies were included if they evaluated the association of mortality in patients who initiated MCS (specifically intra-aortic balloon pump (IABP), Impella, and venoarterial extracorporeal membrane oxygenation (VA-ECMO)) before PPCI versus after PPCI, specifically in patients with STEMI complicated by CS. Data were integrated using the random-effects models. Ten studies involving 1,352 patients (956, 203, and 193 patients underwent IABP, Impella, and VA-ECMO respectively) with STEMI complicated by CS were included. There was no difference in mortality using IABP before or after PPCI ([OR] 1.77, 95% CI 0.77-1.61, I2 = 27%, p = 0.57). Nevertheless, Impella and VA-ECMO started before PPCI were significantly associated with a reduced risk of mortality compared to that started after PPCI ([OR] 0.49, 95% CI 0.26-0.92, I2 = 0%, p = 0.03 and [OR] 0.29, 95% CI 0.14-0.62, I2 = 0%, p = 0.001, respectively). In patients with STEMI complicated by CS undergoing PPCI, the use of IMPELLA or VA-ECMO prior to PPCI significantly decreased mortality, in contrast to IABP, in which no difference in mortality was found between using it before or after PPCI. More rigorous studies are needed to clarify this association.

Transradial versus Transfemoral Access and the Risk of Acute Kidney Injury following Primary Percutaneous Coronary Intervention in Patients with ST-Elevation Myocardial Infarction: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Propensity-Score-Matched Studies

J Interv Cardiol · Mar 2022

Gaspar Del Rio-Pertuz, Michel Juarez, Poemlarp Mekraksakit, Kanak Parmar, Mohammad M Ansari

Abstract

The aim of this study is to examine the association between vascular access sites and the incidence of AKI in patients with STEMI undergoing primary PCI. Emerging evidence has suggested that transradial access (TRA) may be associated with lower rates of acute kidney injury (AKI) as compared with transfemoral access (TFA). However, most of these studies have included a nonselected study population undergoing diagnostic cardiac catheterization or percutaneous coronary intervention (PCI). Data on the association between TRA and AKI in this setting of STEMI are limited and with conflicting results. We systematically searched PubMed, Embase, and Scopus for abstracts and full-text articles from inception to July 13th of 2021. Studies included were randomized controlled trials (RCTs) and propensity-score-matched (PSM) studies evaluating the association of TRA versus TFA access with AKI in patients undergoing primary PCI for STEMI. Data were integrated using the random effects model and generic inverse-variance method of DerSimonian and Laird. A total of 10,093 studies were found. After applying our inclusion criteria, 5 studies from 2014 to 2021 with a total of 8,536 STEMI patients were included. TRA was not significantly associated with a reduced risk for AKI compared with TFA (odds ratio 0.85, 95% CI 0.71-1.01, p 0.07, I 2 = 40%). Transradial access was not significantly associated with lower risk of AKI in patients undergoing primary PCI for STEMI compared with TFA. Larger studies are needed to clarify this outcome.

Interrogating and Reflecting on Disability Prevalence Data Collected Using the Washington Group Tools: Results from Population-Based Surveys in Cameroon, Guatemala, India, Maldives, Nepal, Turkey and Vanuatu

Int J Environ Res Public Health · Aug 2021

Islay Mactaggart, Ammar Hasan Bek, Lena Morgon Banks, Tess Bright, Carlos Dionicio, Shaffa Hameed, et al.

Abstract

The Washington Group (WG) tools capture self-reported functional limitations, ranging from 6 domains in the Short Set (SS) to 11 in the Extended Set (ESF). Prevalence estimates can vary considerably on account of differences between modules and the different applications of them. We compare prevalence estimates by WG module, threshold, application and domain to explore these nuances and consider whether alternative combinations of questions may be valuable in reduced sets. We conducted secondary analyses of seven population-based surveys (analyses restricted to adults 18+) in Low- and Middle-Income Countries that used the WG tools. The prevalence estimates using the SS standard threshold (a lot of difficulty or higher in one or more domain) varied between 3.2% (95% Confidence Interval 2.9-3.6) in Vanuatu to 14.1% (12.2-16.2) in Turkey. The prevalence was higher using the ESF than the SS, and much higher (5 to 10-fold) using a wider threshold of "some" or greater difficulty. Two of the SS domains (communication, self-care) identified few additional individuals with functional limitations. An alternative SS replacing these domains with the psychosocial domains of anxiety and depression would identify more participants with functional limitations for the same number of items. The WG tools are valuable for collecting harmonised population data on disability. It is important that the impact on prevalence of use of different modules, thresholds and applications is recognised. An alternative SS may capture a greater proportion of people with functional domains without increasing the number of items.

Diet quality, school attendance, and body weight status in adolescent girls in rural Guatemala

Ann N Y Acad Sci · Jan 2021

Violeta Chacón, Qinran Liu, Yikyung Park, Peter Rohloff, Joaquin Barnoya

Abstract

A cluster of factors affects nutritional status among adolescent girls in low- and middle-income countries (LMICs). We investigated the association between school attendance and diet quality among 498 rural adolescent girls (352 attending and 146 not attending school) in Tecpán, Guatemala. In a cross-sectional study, we collected sociodemographic and anthropometric data and characterized the dietary intake using a Food Frequency Questionnaire. We then calculated diet quality using the Healthy Eating Score (HES). Multiple linear regression models were conducted to evaluate the effects of school attendance on diet quality. We found that the overall diet quality among the study participants was poor, according to the HES. However, those who attended school had significantly higher intakes of vitamin A-rich fruits and vegetables (P = 0.04), other fruits (P = 0.01), and milk and milk products (P = 0.004), but a higher intake of fast foods, chips, and saturated fatty acids (P < 0.001). Furthermore, the effects of school attendance on diet quality were significant after adjusting for sociodemographic and lifestyle factors (β coefficient = -1.70, 95% CI: -3.30 to -0.11) but was attenuated when further adjusted for weight status (β coefficient = -1.58, 95% CI: -3.17 to 0.02). Our findings suggest that diet quality among girls in rural Guatemala is poor, particularly among those who do not attend school. To advance our understanding of adolescent diet in LMICs, future studies should include adolescents who are out of school.

Feasibility of satellite image and GIS sampling for population representative surveys: a case study from rural Guatemala

Int J Health Geogr · Dec 2020

Ann C Miller, Peter Rohloff, Alexandre Blake, Eloin Dhaenens, Leah Shaw, Eva Tuiz, et al.

Abstract

Population-representative household survey methods require up-to-date sampling frames and sample designs that minimize time and cost of fieldwork especially in low- and middle-income countries. Traditional methods such as multi-stage cluster sampling, random-walk, or spatial sampling can be cumbersome, costly or inaccurate, leading to well-known biases. However, a new tool, Epicentre's Geo-Sampler program, allows simple random sampling of structures, which can eliminate some of these biases. We describe the study design process, experiences and lessons learned using Geo-Sampler for selection of a population representative sample for a kidney disease survey in two sites in Guatemala. We successfully used Epicentre's Geo-sampler tool to sample 650 structures in two semi-urban Guatemalan communities. Overall, 82% of sampled structures were residential and could be approached for recruitment. Sample selection could be conducted by one person after 30 min of training. The process from sample selection to creating field maps took approximately 40 h. In combination with our design protocols, the Epicentre Geo-Sampler tool provided a feasible, rapid and lower-cost alternative to select a representative population sample for a prevalence survey in our semi-urban Guatemalan setting. The tool may work less well in settings with heavy arboreal cover or densely populated urban settings with multiple living units per structure. Similarly, while the method is an efficient step forward for including non-traditional living arrangements (people residing permanently or temporarily in businesses, religious institutions or other structures), it does not account for some of the most marginalized and vulnerable people in a population-the unhoused, street dwellers or people living in vehicles.

Impact of school and work status on diet and physical activity in rural Guatemalan adolescent girls: a qualitative study

Ann N Y Acad Sci · Jul 2019

Sophie Kurschner, Luisa Madrigal, Violeta Chacon, Joaquin Barnoya, Peter Rohloff

Abstract

In low- and middle-income countries, gender norms and access to energy-dense, nutrient-poor foods are well-studied determinants of food and physical activity choices for adolescent girls. However, most work has been done in urban and school settings. In many settings, a large proportion of the adolescent population is rural or not enrolled in school. We conducted in-depth interviews with 20 adolescent girls (ages 15-19) in Tecpán, Guatemala, a rural, largely indigenous Maya community. Interviews were coded and themes analyzed for insights into eating habits, food choices, and physical activity. Twelve participants were enrolled in school and eight were employed and not in school. Girls enrolled in school had more disrupted eating schedules and consumed more energy-dense, nutrient-poor foods. Girls not enrolled in school had fewer opportunities for physical activity and were more sedentary. To our knowledge, this study is the first in a low- and middle-income country to consider diet and physical activity of adolescent girls enrolled and not enrolled in school. Key implications include (1) the need to reduce exposure to nutrient-poor foods and promote healthy eating schedules in schools, and (2) the need to create community-based opportunities for the activity for girls no longer enrolled in school.

Wearables for Pediatric Rehabilitation: How to Optimally Design and Use Products to Meet the Needs of Users

Phys Ther · Jun 2019

Michele A Lobo, Martha L Hall, Ben Greenspan, Peter Rohloff, Laura A Prosser, Beth A Smith

Abstract

This article will define "wearables" as objects that interface and move with users, spanning clothing through smart devices. A novel design approach merging information from across disciplines and considering users' broad needs will be presented as the optimal approach for designing wearables that maximize usage. Three categories of wearables applicable to rehabilitation and habilitation will be explored: (1) inclusive clothing (eg, altered fit, fasteners); (2) supportive wearables (eg, orthotics, exoskeletons); and (3) smart wearables (eg, with sensors for tracking activity or controlling external devices). For each category, we will provide examples of existing and emerging wearables and potential applications for assessment and intervention with a focus on pediatric populations. We will discuss how these wearables might change task requirements and assist users for immediate effects and how they might be used with intervention activities to change users' abilities across time. It is important for rehabilitation clinicians and researchers to be engaged with the design and use of wearables so they can advocate and create better wearables for their clients and determine how to most effectively use wearables to enhance their assessment, intervention, and research practices.

An open source autocorrelation-based method for fetal heart rate estimation from one-dimensional Doppler ultrasound

Physiol Meas · Feb 2019

Camilo E Valderrama, Lisa Stroux, Nasim Katebi, Elianna Paljug, Rachel Hall-Clifford, Peter Rohloff, et al.

Abstract

Open research on fetal heart rate (FHR) estimation is relatively rare, and evidence for the utility of metrics derived from Doppler ultrasound devices has historically remained hidden in the proprietary documentation of commercial entities, thereby inhibiting its assessment and improvement. Nevertheless, recent studies have attempted to improve FHR estimation; however, these methods were developed and tested using datasets composed of few subjects and are therefore unlikely to be generalizable on a population level. The work presented here introduces a reproducible and generalizable autocorrelation (AC)-based method for FHR estimation from one-dimensional Doppler ultrasound (1D-DUS) signals. Simultaneous fetal electrocardiogram (fECG) and 1D-DUS signals generated by a hand-held Doppler transducer in a fixed position were captured by trained healthcare workers in a European hospital. The fECG QRS complexes were identified using a previously published fECG extraction algorithm and were then over-read to ensure accuracy. An AC-based method to estimate FHR was then developed on this data, using a total of 721 1D-DUS segments, each 3.75 s long, and parameters were tuned with Bayesian optimization. The trained FHR estimator was tested on two additional (independent) hand-annotated Doppler-only datasets recorded with the same device but on different populations: one composed of 3938 segments (from 99 fetuses) acquired in rural Guatemala, and another composed of 894 segments (from 17 fetuses) recorded in a hospital in the UK. The proposed AC-based method was able to estimate FHR within 10% of the reference FHR values 96% of the time, with an accuracy of 97% for manually identified good quality segments in both of the independent test sets. This is the first work to publish open source code for FHR estimation from 1D-DUS data. The method was shown to satisfy estimations within 10% of the reference FHR values and it therefore defines a minimum accuracy for the field to match or surpass. Our work establishes a basis from which future methods can be developed to more accurately estimate FHR variability for assessing fetal wellbeing from 1D-DUS signals.

Blending Western Biomedicine with Local Healing Practices

AMA J Ethics · Jul 2016

Anita Chary, Carolyn Sargent

Abstract

Western allopathic physicians working internationally might encounter allopathic colleagues who endorse local healing practices that are not scientifically supported and, hence, might pose harm to patients. Respect for the autonomy of local physicians and patients thus can conflict with the ethical principles of beneficence and nonmaleficence. In such a situation, it is advisable for Western allopathic physicians to communicate their concerns to local colleagues as equal partners. Making an effort to understand local meanings associated with a traditional therapy demonstrates one's respect for local cultural ideas and practices, even if one disagrees with that therapy, and is crucial to tailoring messages about clinical practice change. A realistic approach to cross-cultural clinical practice change seeks to reduce, rather than eliminate, harm.