G Escalona

Department of Biomedical Engineering, University of Michigan, Ann Arbor; MI, 48109, USA.

37 publications 1910 – 2025 ORCID

Research Overview

G. Escalona is a surgical educator focused on making high-quality surgical training accessible beyond traditional academic centers, particularly through simulation-based programs, remote asynchronous feedback platforms, and AI-assisted assessment tools. Much of the work centers on laparoscopic and procedural skills training in Latin America, using digital platforms to train surgeons and first responders in resource-constrained settings. A parallel thread of research investigates biomaterial scaffolds for early cancer detection and monitoring of treatment response.

Publications

Quality matters: Artificial intelligence-based assessment of feedback quality predicts technical skill improvement.

2025

Surgery

Kewalramani D, Roman DS, Lagos SA, Rammsy F, Villagran I +7 more

Plain English
An AI tool called Teach1 was used to evaluate the quality of feedback given to 75 medical students during simulated paracentesis training, scoring feedback on five criteria including specificity and actionability. Higher feedback quality scores correlated directly with greater technical skill improvement, with each 10% increase in feedback quality corresponding to about a 1.2-point gain on a standardized skills assessment. AI-based feedback quality assessment is a scalable way to improve teaching effectiveness in procedural training programs.

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Enhancing Competency in Bariatric-Metabolic Surgery: The Impact of Simulation-Based Training on Surgeons' Experience.

2025

Journal of laparoendoscopic & advanced surgical techniques. Part A

Figueroa U, Sanhueza D, Grimoldi M, Cruz E, Selman R +9 more

Plain English
Surgeons who completed a simulation-based bariatric surgery training course between 2018 and 2023 were surveyed on its impact: 97% reported improvements in technique and outcomes, and 90% said the course increased their confidence. The course also increased surgeons' reported exposure to complex cases and was rated especially relevant for sleeve gastrectomy and bypass procedures. The findings support simulation as a meaningful complement to clinical training in building bariatric surgical competence.

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From fighting fires to halting hemorrhage: the use of a self-training module to teach tourniquet placement to first responder firefighters in a resource-constrained area.

2025

Injury

Levi A, Monzón JC, Jhunjhunwala R, Escalona G, Zinco A +3 more

Plain English
Guatemalan firefighters — who lead trauma responses in that country without medical training — were taught tourniquet application using CrashSavers, a free self-administered mobile phone-based training program including videos, virtual reality cases, and a DIY bleeding simulator. After training, time to stop simulated bleeding dropped from 58 to 39 seconds, and 18 months later the firefighters retained both the skill and their confidence. A low-cost, self-directed digital training tool can successfully build and sustain life-saving hemorrhage control skills in first responders in resource-limited settings.

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Solo surgeon ambulatory magnetic-assisted robotic surgery (MARS): initial 51 cases with high patient satisfaction.

2025

Surgical endoscopy

Spurzem GJ, Jimenez J, Paravic N, Robles I, Yañez M +6 more

Plain English
This retrospective review evaluated 51 outpatient laparoscopic cholecystectomies performed by a solo surgeon using the Magnetic-Assisted Robotic Surgery (MARS) platform, which provides camera control and internal tissue retraction without a surgical assistant. All patients were discharged within 6 hours, there were no complications or readmissions, and 92.5% were very satisfied with the system. MARS enables safe, efficient solo laparoscopic cholecystectomy with high patient satisfaction, potentially reducing operative staffing requirements.

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Early metastasis is characterized by Gr1+ cell dysregulation and is inhibited by immunomodulatory nanoparticles.

2025

Molecular oncology

Ma JA, Orbach SM, Griffin KV, Kang K, Zhang Y +5 more

Plain English
Using a mouse model of metastatic breast cancer, researchers found that Gr1+ myeloid immune cells in the lungs — but not in blood — transition to tumor-supportive phenotypes as early metastatic disease develops. This shift was linked to a signaling protein called CHI3L1, and injecting polymeric nanoparticles intravenously reprogrammed these cells, reduced CHI3L1 secretion, and inhibited metastasis. Targeting dysregulated myeloid cells at the metastatic site with nanoparticles is a potential early intervention strategy for breast cancer spread.

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Innovation Meets Practice: A Scalable Simulation-based Methodology for Massive Paracentesis Training.

2025

Gastroenterology

Figueroa Ú, Jarry C, Inzunza M, Montero I, Garrido F +5 more

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Design and validation of a simulation-based training module for ileo-transverse intracorporeal anastomosis.

2025

Surgical endoscopy

Jarry C, Varas J, Inzunza M, Escalona G, Machuca E +3 more

Plain English
Researchers developed and validated a simulation model for training surgeons in intracorporeal ileo-transverse anastomosis — a technically demanding step in laparoscopic right colon removal where surgeons sew inside the abdomen. The ex-vivo model was rated as having acceptable surgical fidelity by 83% of participants, and expert surgeons scored significantly higher and operated faster than novices on the model, confirming it distinguishes skill levels. The simulation provides a dedicated training tool for a procedure that has limited adoption partly due to its technical difficulty.

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Detecting metastatic potential of cancer through longitudinal vasculature imaging of biomaterial scaffold using non-invasivephotoacoustic microscopy and optical coherence tomography.

2025

Theranostics

Xu Z, Escalona G, Schrack I, Zhang W, Zhai T +2 more

Plain English
This study used photoacoustic microscopy and optical coherence tomography to monitor blood vessel changes within a subcutaneous biomaterial scaffold that recruits cancer cells — functioning as an engineered detection site for metastasis. In mice with metastatic breast cancer models, disorganized and accelerated vascular remodeling at the scaffold was detectable within 8 days of tumor injection, well before conventional signs of spread. Longitudinal vascular imaging of a biomaterial implant could provide an early non-invasive window into metastatic disease progression.

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Design Principles of an Engineered Metastatic Niche for Monitoring of Cancer Progression.

2025

Biotechnology and bioengineering

Escalona G, Ocadiz-Ruiz R, Ma JA, Schrack IA, Ross BC +3 more

Plain English
This study defined the physical design requirements for a subcutaneous porous scaffold implant intended to serve as a synthetic site that captures tumor cells before they colonize vital organs. A porous structure was essential for capturing both tumor and immune cells, scaffolds as small as 2 mm detected disease accurately, and scaffolds implanted for 1-5 weeks were effective sensors. Critically, the scaffold detected metastatic disease at earlier time points than liquid biopsy, establishing it as a sensitive early detection platform.

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Longitudinal Monitoring of T cell Dynamics in Metastatic Breast Cancer via a Remote Diagnostic Implant.

2024

Immunomedicine

Schrack IA, Pereles RS, Ross BC, Ma JA, Urie RR +6 more

Plain English
Using a subcutaneous biomaterial scaffold implant in a mouse model of metastatic triple-negative breast cancer, researchers tracked how T cell populations at the implant changed with disease progression. CD8+ T cells shifted from naive to effector memory states, and regulatory T cells were reduced at both the scaffold and in the lung as disease advanced — patterns that mirrored those in the actual metastatic organ. The scaffold provides a surgically accessible, non-vital tissue for longitudinal immune monitoring that could guide immunotherapy decisions.

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Improving Medical Student Performance With Unsupervised Simulation and Remote Asynchronous Feedback.

2024

Journal of surgical education

Varas J, Belmar F, Fuentes J, Vela J, Contreras C +8 more

Plain English
This randomized study compared two training methods for medical students learning thoracentesis and paracentesis: unsupervised simulation with remote asynchronous feedback versus a two-hour in-person workshop. Students in the remote feedback group had significantly higher passing rates (80% vs. 43% for thoracentesis; 91% vs. 67% for paracentesis). Self-directed simulation with remote expert feedback outperforms traditional workshops for teaching procedural skills, while offering greater scheduling flexibility for both students and instructors.

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Engineered Immunologic Niche Monitors Checkpoint Blockade Response and Probes Mechanisms of Resistance.

2024

Immunomedicine

Raghani RM, Urie RR, Ma JA, Escalona G, Schrack IA +7 more

Plain English
This study used a subcutaneous biomaterial implant to monitor immune gene expression before, during, and after anti-PD-1 immunotherapy in a mouse model of triple-negative breast cancer. Myeloid cell function at the implant site distinguished tumors that responded to treatment from those that resisted it, and a gene signature from the implant predicted response before treatment began. Longitudinal biopsy of an accessible implant could enable personalized immunotherapy decisions and mechanistic investigation of resistance.

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A low-cost, DIY tourniquet simulator with built-in self-assessment for prehospital providers in Guatemala city.

2024

World journal of surgery

Jhunjhunwala R, Monzon J, Faria I, Escalona G, Zinco A +4 more

Plain English
This study validated a low-cost tourniquet training system for prehospital providers in Guatemala, consisting of a mobile app with didactic content and a physical simulator made from inexpensive materials. The simulator successfully distinguished expert from novice skill before training, and pre- vs. post-training comparisons showed significantly faster and more confident tourniquet application after the program. The self-assessment features enable independent learning, reducing reliance on constant instructor availability in resource-constrained settings.

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Taking advantage of asynchronous digital feedback: development of an at-home basic suture skills training program for undergraduate medical students that facilitates skills retention.

2023

Global surgical education : journal of the Association for Surgical Education

Belmar F, Gaete MI, Durán V, Chelebifski S, Jarry C +8 more

Plain English
This study tested whether medical students could learn basic suturing skills through home-based unsupervised practice with remote asynchronous feedback delivered within 72 hours, with 243 students completing the course. Students achieved significantly higher scores than historical cohorts trained with in-person expert feedback or video-guided learning alone, and a subgroup assessed at 6 months showed retention of skills. Remote asynchronous feedback through a digital platform enables high-quality suture skill acquisition and retention without requiring instructor presence.

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Innovations in surgical training: exploring the role of artificial intelligence and large language models (LLM).

2023

Revista do Colegio Brasileiro de Cirurgioes

Varas J, Coronel BV, Villagrán I, Escalona G, Hernandez R +6 more

Plain English
This paper reviews how artificial intelligence and large language models (LLMs) could transform surgical training by personalizing feedback, transcribing and translating assessment conversations, supporting simulation, and automating skill evaluation. While AI tools show clear potential for expanding access to quality surgical education, the authors identify key challenges including accuracy limitations, privacy concerns, bias in training data, and integration with existing systems. The paper frames AI not as a replacement for surgical mentors but as a scalable tool to extend their reach.

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Five-Year Experience Training Surgeons with a Laparoscopic Simulation Training Program for Bariatric Surgery: a Quasi-experimental Design.

2023

Obesity surgery

Duran Espinoza V, Belmar Riveros F, Jarry Trujillo C, Gaete Dañobeitia MI, Montero Jaras I +7 more

Plain English
This report describes five years of a simulation training program for laparoscopic Roux-en-Y gastric bypass at a single center, where 68 surgeons completed a structured curriculum using animal models to practice the critical anastomosis steps. Pre-to-post-training scores improved significantly across all measures — technique quality, speed, leak rates, and permeability — demonstrating that structured simulation can build gastric bypass skills in a safe setting. The program addresses a real gap, given that mastering this operation in patients typically requires 50-500 cases.

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REMOTE ASYNCHRONOUS FEEDBACK FOR UNSUPERVISED LAPAROSCOPIC TRAINING: THE "LAPP" PLATFORM.

2023

Arquivos brasileiros de cirurgia digestiva : ABCD = Brazilian archives of digestive surgery

Ulloa G, Neyem A, Escalona G, Ortiz C, Varas J

Plain English
This study developed and tested Lapp, a digital platform that allows surgical trainees to upload videos of their laparoscopic simulation practice and receive personalized feedback from remote instructors. A group trained with Lapp's remote asynchronous feedback performed at the same competency level as a group that received traditional in-person feedback from 130 participants. Remote digital feedback through Lapp is as effective as in-person instruction, removing geographic and time barriers to quality surgical simulation training.

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Artificial intelligence in laparoscopic simulation: a promising future for large-scale automated evaluations.

2023

Surgical endoscopy

Belmar F, Gaete MI, Escalona G, Carnier M, Durán V +7 more

Plain English
Researchers trained an AI algorithm to evaluate basic laparoscopic simulation exercises using 400 bean-drop and 480 peg-transfer training videos, then tested its agreement with expert human evaluators on 107 additional videos. Agreement was 80% for bean drop and 93% for peg transfer, with near-perfect agreement for the peg transfer task. AI-based assessment of laparoscopic simulation exercises is feasible and could scale objective skills evaluation across large training networks without requiring additional expert evaluator time.

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Remote and asynchronous training network: from a SAGES grant to an eight-country remote laparoscopic simulation training program.

2023

Surgical endoscopy

Gaete MI, Belmar F, Cortés M, Alseidi A, Asbun D +7 more

Plain English
This report describes the expansion of a remote simulation training model from a single center to 14 institutions across 8 countries in Latin America, using a digital platform to deliver instruction and collect asynchronous feedback from a small network of trained instructors. Over three years, 369 learners completed training generating over 6,700 videos and 28,700 feedback inputs, with training centers run entirely by non-physician administrators. The model proves that high-quality simulation training can be scaled internationally without on-site instructors, using technology to bridge geographic and resource gaps.

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Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations.

2022

BioMed research international

Cornejo J, Cornejo-Aguilar JA, Vargas M, Helguero CG, Milanezi de Andrade R +27 more

Plain English
This international review covers how 3D printing technology is being used across surgical specialties — from neurosurgery and cardiac surgery to orthopedics and urology — to create patient-specific anatomical models for preoperative planning, intraoperative guidance, and surgical training. Integration with virtual, mixed, and augmented reality platforms is also examined as a path toward fully personalized surgical simulation. The review also explores early work on developing surgical tools designed for use in space under variable gravity conditions.

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Transgastric repair of transfixing gastroesophageal junction gunshot wound: video case report.

2021

Journal of surgical case reports

Vela J, Contreras C, Varas J, Ottolino P, Ramos JP +4 more

Plain English
This video case report describes the surgical repair of a transfixing gunshot wound to the gastroesophageal junction — the connection between the esophagus and stomach — in a 23-year-old man who arrived hemodynamically stable. Primary repair of the perforation was performed and reinforced with a partial stomach wrap, along with repair of concurrent diaphragm and liver injuries. The patient recovered without complications, demonstrating that stable GEJ gunshot wounds can be managed successfully with direct primary repair.

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Minimally invasive tele-mentoring opportunity-the mito project.

2020

Surgical endoscopy

Quezada J, Achurra P, Jarry C, Asbun D, Tejos R +7 more

Plain English
This study developed and tested Lapp, a smartphone app enabling remote teacher-student interaction for laparoscopic simulation training, comparing its outcomes to traditional in-person training at two centers. Both groups improved significantly from pre- to post-training, and performance levels between the Lapp and in-person groups were statistically comparable. Remote, app-based simulation training is as effective as in-person instruction for acquiring advanced laparoscopic skills, opening surgical education to geographically isolated trainees.

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Smartphone application supplements laparoscopic training through simulation by reducing the need for feedback from expert tutors.

2019

Surgery open science

Quezada J, Achurra P, Asbun D, Polom K, Roviello F +5 more

Plain English
This randomized study tested whether a smartphone app guiding trainees through advanced laparoscopic simulation could reduce their need to ask instructors for help, comparing app users (YAPP) versus non-users (NAPP). App users requested instructor feedback 4 times per session versus 13 for non-users, with no difference in final skills performance between groups. The app reduces dependence on instructor availability without compromising the quality of skill development, making simulation programs more scalable.

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pH-Responsive Polyacetal-Protein Conjugates Designed for Polymer Masked-Unmasked Protein Therapy (PUMPT).

2018

Macromolecular bioscience

Escalona GR, Sanchis J, Vicent MJ

Plain English
This study designed a biodegradable polymer system that masks a therapeutic protein (trypsin as a model) at neutral blood pH and releases it when the pH drops — as happens in tumors, injured tissue, or cellular compartments. At acidic pH the polymer degrades and protein activity is restored, providing a triggered release mechanism that does not depend on specific enzymes being present at the target site. This pH-responsive approach overcomes a key limitation of earlier protein therapy systems and could be applied to many disease contexts.

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Multidrug- and Extensively Drug-Resistant UropathogenicClinical Strains: Phylogenetic Groups Widely Associated with Integrons Maintain High Genetic Diversity.

2016

Frontiers in microbiology

Ochoa SA, Cruz-Córdova A, Luna-Pineda VM, Reyes-Grajeda JP, Cázares-Domínguez V +10 more

Plain English
This study characterized 103 multidrug-resistant and extensively drug-resistant uropathogenic E. coli strains from clinical isolates, finding that resistance was concentrated in phylogenetic groups D and B2 and strongly associated with class 1 and 2 integrons — mobile genetic elements that carry multiple resistance genes. Virulence genes including those for fimbriae, iron uptake, and toxins were prevalent across resistant strains. The co-occurrence of resistance and virulence in these clonal groups makes them particularly dangerous pathogens requiring close surveillance.

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Vancomycin modifies the expression of the agr system in multidrug-resistant Staphylococcus aureus clinical isolates.

2015

Frontiers in microbiology

Cázares-Domínguez V, Ochoa SA, Cruz-Córdova A, Rodea GE, Escalona G +4 more

Plain English
This study examined how the antibiotic vancomycin affects the expression of virulence-related genes in multidrug-resistant Staphylococcus aureus clinical isolates. Vancomycin significantly increased expression of the spa gene (which encodes protein A), boosted protein A production, and promoted biofilm formation during late growth phases. These results suggest vancomycin may paradoxically enhance certain virulence behaviors in resistant S. aureus, with potential implications for treatment failure.

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Vancomycin tolerant, methicillin-resistant Staphylococcus aureus reveals the effects of vancomycin on cell wall thickening.

2015

PloS one

Cázares-Domínguez V, Cruz-Córdova A, Ochoa SA, Escalona G, Arellano-Galindo J +4 more

Plain English
This study characterized 12 vancomycin-tolerant MRSA isolates from pediatric patients, finding that exposure to vancomycin caused an average 24 nm (105%) thickening of the bacterial cell wall. The majority of isolates carried the agr type II and SCCmec II genetic profiles, which are associated with hospital-acquired infections. Cell wall thickening is a key adaptive mechanism by which these bacteria survive antibiotic exposure, explaining why higher vancomycin concentrations may be needed to treat these infections.

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Phenotypic characterization of multidrug-resistant Pseudomonas aeruginosa strains isolated from pediatric patients associated to biofilm formation.

2015

Microbiological research

Ochoa SA, Cruz-Córdova A, Rodea GE, Cázares-Domínguez V, Escalona G +4 more

Plain English
This study assessed biofilm formation in 58 multidrug-resistant Pseudomonas aeruginosa strains from a pediatric hospital in Mexico, finding strong correlations between biofilm production and both exopolysaccharide secretion and twitching motility via type-IV pili. Over 50% of strains were resistant to 12 antibiotics, and most clustered into a dominant genetic group by PFGE. The close association between resistance, biofilm, and motility in these strains explains why P. aeruginosa infections in immunocompromised pediatric patients are so difficult to eradicate.

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Molecular analysis and distribution of multidrug-resistant Enterococcus faecium isolates belonging to clonal complex 17 in a tertiary care center in Mexico City.

2013

BMC microbiology

Ochoa SA, Escalona G, Cruz-Córdova A, Dávila LB, Saldaña Z +6 more

Plain English
This study identified 12 vancomycin-resistant Enterococcus faecium strains from pediatric patients at a Mexican hospital, finding that all belonged to the virulent clonal complex 17 lineage and showed 100% resistance to nine antibiotic classes. MLST identified four sequence types, and the presence of the esp and hyl virulence genes in most isolates confirms their capacity for hospital spread. This first report of CC17 VRE in Mexico underscores the need for active surveillance to catch emerging resistant clones before they become entrenched.

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pep27 and lytA in Vancomycin-Tolerant Pneumococci.

2011

Journal of microbiology and biotechnology

Olivares A, Trejo JO, Arellano-Galindo J, Zuñiga G, Escalona G +5 more

Plain English
This study examined whether vancomycin treatment altered the expression of two genes — lytA and pep27 — involved in the tolerance of Streptococcus pneumoniae to antibiotics. In vancomycin-tolerant strains, pep27 expression did not increase in the stationary growth phase as it does in sensitive strains, which may explain how these bacteria survive antibiotic pressure that would normally trigger cell death. The absence of this growth phase response to pep27 appears to be a mechanism underlying vancomycin tolerance in pneumococci.

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Variation in plasma cholinesterase activity in the clay-colored robin (Turdus grayi) in relation to time of day, season, and diazinon exposure.

2010

Ecotoxicology (London, England)

Cobos VM, Mora MA, Escalona G, Calme S, Jiménez J

Plain English
This field and laboratory study measured how cholinesterase enzyme activity — a marker of pesticide exposure — varies in the clay-colored robin by time of day, season, and experimental diazinon dosing. Activity varied 20% within two hours during the day and differed significantly between seasons, while the highest diazinon dose caused 73% inhibition. The study provides baseline variation data essential for correctly interpreting pesticide biomonitoring results in this tropical songbird species.

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[Pulmonary hamartoma: case report of the bilateral diffuse fibro-adenomatous variety in a 53-year-old woman].

1959

Revista de investigacion clinica; organo del Hospital de Enfermedades de la Nutricion

GARCIA S, ESCALONA G

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[New ideas in the treatment of pulmonary tuberculosis].

1954

Revista mexicana de tuberculosis y enfermedades del aparato respiratorio

GOMEZ PIMIENTA JL, ESCALONA G, MACIAS S

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[New ideas regarding the treatment of pulmonary tuberculosis].

1953

Gaceta medica de Mexico

GOMEZ PIMIENTA JL, ESCALONA G, MACIAS GALLARDO S

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[Secondary carcinoma of the liver; importance of biopsy for localization of primary lesion].

1953

Revista de investigacion clinica; organo del Hospital de Enfermedades de la Nutricion

RIVERA A, ROJAS E, ESCALONA G

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[Incipient pulmonary cancer].

1953

La Prensa medica mexicana

ESCALONA G

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Prophylactic Measures in Exanthematic Typhus.

1910

American journal of public hygiene

Escalona G

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Publication data sourced from PubMed . Plain-English summaries generated by AI. Not medical advice.