Juan O. Talavera

Dr. Juan O. Talavera


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 March 2019 in Nutrients
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Journal Article
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MFMaría Eugenia Flores-Quijano
María Eugenia Flores-Quijano
RVRodrigo Vega-Sánchez
Rodrigo Vega-Sánchez
MTMari Cruz Tolentino-Dolores
Mari Cruz Tolentino-Dolores
MLMardia López-Alarcón
Mardia López-Alarcón
MFMónica Crissel Flores-Urrutia
Mónica Crissel Flores-Urrutia
JTJuan O. Talavera
Juan O. Talavera
The influence of obesity on maternal iron homeostasis and nutrition status during pregnancy remains only partially clarified. Our study objectives were (1) to describe how obesity influences broad iron nutrition spectrum biomarkers such as available or circulating iron (serum transferrin receptor (sTfr) and serum iron), iron reserves (ferritin), and functional iron (hemoglobin); and (2) to depict the regulating role of hepcidin. The above was carried out while considering influential factors such as initial iron nutrition status, iron intake, and the presence of inflammation. Ninety three non-anemic pregnant adult women were included, 40 with obesity (Ob) and 53 with adequate weight (AW); all took ≈30 mg/day of supplementary iron. Information on iron intake and blood samples were obtained at gestational weeks 13, 20, 27, and 35. A series of repeated measure analyses were performed using General Linear Models to discern the effect of obesity on each iron indicator; iron intake, hepcidin, and C-reactive protein were successively introduced as covariates. Available and circulating iron was lower in obese women: sTfr was higher (p = 0.07) and serum iron was lower (p = 0.01); and ferritin and hemoglobin were not different between groups. Hepcidin was higher in the Ob group (p = 0.01) and was a significant predictor variable for all biomarkers. Obesity during pregnancy dysregulates iron homeostasis, resembling “obesity hypoferremia”.

18 September 2020 in The Journal of Clinical Endocrinology & Metabolism
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MMMoises Mercado
Moises Mercado
CACoralys Abreu
Coralys Abreu
AVAlma Vergara-López
Alma Vergara-López
BGBaldomero José Gregorio González-Virla
Baldomero José Gregorio González-Virla
AEAna-Laura Espinosa-De-Los-Monteros
Ana-Laura Espinosa-De-Los-Monteros
JTJuan O. Talavera
Juan O. Talavera
Context: Acromegaly registries constitute a valuable source of therapeutic outcome information in real-life. Objective: The objective of this work is to analyze surgical and pharmacological outcomes in the Mexican Acromegaly Registry (MAR). Design and Methods: Data were extracted from the MAR informatic platform. Surgical remission was defined by a postoperative postglucose (GH) of less than 1 ng/mL and an insulin-like growth factor 1 (IGF-1) of less than 1.2 × upper limit of normal (ULN). Pharmacological remission was defined by a basal GH of less than 1 ng/mL and an IGF-1 of less than 1.2 × ULN. Results: A total of 650 surgical outcomes were analyzed (94.6% transsphenoidal). Surgical remission was achieved in 40.15%, whereas 44.15% remained biochemically active. Persistently active disease after surgery was significantly associated with harboring an invasive macroadenoma, a basal GH of greater than 10 ng/mL, and/or an IGF-1 of greater than 2 × ULN at diagnosis on bivariate and multivariate analysis. The outcome of monotherapy with first-generation somatostatin analogs (SSAs) was evaluated in 267 patients (adjunctive in 65%), of whom 28.4% achieved remission. Persistently active disease was significantly associated with harboring an invasive macroadenoma as well as with pretreatment basal GH and IGF-1 levels of greater than 10 ng/mL and greater than 2 × ULN, respectively, on bivariate and multivariate analysis. Combined therapy with SSA and cabergoline was analyzed in 100 patients, of whom 19% achieved remission and 44% remained active; in this subset of patients, only a pretreatment IGF-1 of greater than 2 × ULN was significantly associated with persistent disease activity. Conclusion: Surgical and pharmacological outcomes in acromegaly are highly dependent on tumor size/invasiveness as well as on the degree of hypersomatotropinemia.

3 December 2020 in PLOS ONE
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Journal Article
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DMDan Morgenstern-Kaplan
Dan Morgenstern-Kaplan
BBBruno Buitano-Tang
Bruno Buitano-Tang
MMMercedes Martínez-Gil
Mercedes Martínez-Gil
APAndrea Zaldívar-Pérez Pavón
Andrea Zaldívar-Pérez Pavón
JTJuan O. Talavera
Juan O. Talavera
Background: Early identification of different COVID-19 clinical presentations may depict distinct pathophysiological mechanisms and guide management strategies. Objective: To determine the aggressiveness of SARS-CoV-2 using symptom progression in COVID-19 patients. Design: Historic cohort study of Mexican patients. Data from January-April 2020 were provided by the Health Ministry. Setting: Population-based. Patients registered in the Epidemiologic Surveillance System in Mexico. Participants: Subjects who sought medical attention for clinical suspicion of COVID-19. All patients were subjected to RT-PCR testing for SARS-CoV-2. Measurements: We measured the Period between initial symptoms and clinical progression to COVID-19 suspicion (PISYCS) and compared it to the primary outcomes (mortality and pneumonia). Results: 65,500 patients were included. Reported fatalities and pneumonia were 2176 (3.32%), and 11568 (17.66%), respectively. According to the PISYCS, patients were distributed as follows: 14.89% in 7 days. The distribution for mortality and pneumonia was 5.2% and 22.5% in 7 days, respectively (p<0.001). Adjusted-risk of mortality was (OR [95% CI], p-value): <24 hours = 1.75 [1.55–1.98], p<0.001; 1–3 days = 1 (reference value); 4–7 days = 1.53 [1.37–1.70], p7 days = 1.67 [1.44–1.94], p<0.001. For pneumonia: <24 hours = 1.49 [1.39–1.58], p<0.001; 1–3 days = 1; 4–7 days = 1.48 [1.41–1.56], p7 days = 1.57 [1.46–1.69], p<0.001. Limitations: Using a database fed by large numbers of people carries the risk of data inaccuracy. However, this imprecision is expected to be random and data are consistent with previous studies. Conclusion: The PISYCS shows a U-shaped SARS-CoV-2 aggressiveness pattern. Further studies are needed to corroborate the time-related pathophysiology behind these findings.

1 November 2021 in Public Health
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Journal Article
Closed access
RBRuben Blachman-Braun
Ruben Blachman-Braun
JTJuan O. Talavera
Juan O. Talavera
MPM. Pérez-Rodríguez
M. Pérez-Rodríguez
IRI. Roy-García
I. Roy-García
RRR. Rivas-Ruiz
R. Rivas-Ruiz
JSJ. Salmerón-Castro
J. Salmerón-Castro

28 May 2019 in Gaceta Médica de México
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Journal Article
Closed access
JTJuan O. Talavera
Juan O. Talavera
IRIvonne Roy-García
Ivonne Roy-García
LPLino Palacios-Cruz
Lino Palacios-Cruz
RRRodolfo Rivas-Ruiz
Rodolfo Rivas-Ruiz
IHIrma Hoyo
Irma Hoyo
MPMarcela Pérez-Rodríguez
Marcela Pérez-Rodríguez
Research designs refer to the way information is obtained and are limited by ethical, economic and temporal viability. Research designs are standardized strategies to reduce biases, which in the architectural model of research are identified in the baseline state, the maneuver and the outcome; hence, there are no specific designs for each question. The design with the lowest probability of bias is the clinical trial, followed by cohort and case-control studies and, finally, by cross-sectional surveys. Among the main characteristics that give merit to research designs are the following: population inquiry, which refers to the situation of the population in relation to the clinical course/natural history of the disease; the maneuver, or action that is expected to modify the baseline state, which can be observational or experimental; follow-up, or documented monitoring that is given to each subject, which can be longitudinal or cross-sectional; and directionality, which can prolective or retrolective and refers to the timing of data collection for research purposes. It will always be better having a valuable question, even when answered with a design with higher risk of bias, than a question that is irrelevant or has no applicability.

11 July 2025 in Obesity Surgery
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ASAriel Shuchleib
Ariel Shuchleib
DSDaniel Swartz
Daniel Swartz
JTJuan O. Talavera
Juan O. Talavera
EGEdna Elisa Garcia
Edna Elisa Garcia
MMMoises Mercado
Moises Mercado