Melchor Alpizar

Dr. Melchor Alpizar

orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

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

Representative Publications

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25 February 2010 in Diabetes, Obesity and Metabolism
Verified
Journal Article
Closed access
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HPH. M. R. Pattzi
H. M. R. Pattzi
SPS. Pitale
S. Pitale
MAMelchor Alpizar
Melchor Alpizar
CBC. Bennett
C. Bennett
AOA. M. O’farrell
A. M. O’farrell
HGH.‐P. Guler
H.‐P. Guler

1 July 2012 in Talanta
Verified
Journal Article
Closed access
CHC. Henríquez
C. Henríquez
LLL.M. Laglera
L.M. Laglera
MAMelchor Alpizar
Melchor Alpizar
JCJ. Calvo
J. Calvo
FAF. Arduini
F. Arduini
VMVICTOR CERDA MARTIN
VICTOR CERDA MARTIN

7 January 2025 in Medicina
Verified
Journal Article
Open access
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MAMelchor Alpizar
Melchor Alpizar
SSamantha Estefania Olguín Reyes
Samantha Estefania Olguín Reyes
AEAndrea Medina Estévez
Andrea Medina Estévez
JLJulieta Alejandra Saturno Lobos
Julieta Alejandra Saturno Lobos
JCJesús Manuel De Aldecoa Castillo
Jesús Manuel De Aldecoa Castillo
DSDulce María Fernanda Alpízar Sánchez
Dulce María Fernanda Alpízar Sánchez
Introduction: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) stems from disrupted lipid metabolism in the liver, often linked to obesity, type 2 diabetes, and dyslipidemia. In Mexico, where obesity affects 36.9% of adults, MASLD prevalence has risen, especially with metabolic syndrome affecting 56.31% by 2018. MASLD can progress to Metabolic Dysfunction-Associated Steatohepatitis (MASH), affecting 5.27% globally, leading to severe complications like cirrhosis and hepatocellular carcinoma. Background: Visceral fat distribution varies by gender, impacting MASLD development due to hormonal influences. Insulin resistance plays a central role in MASLD pathogenesis, exacerbated by high-fat diets and specific fatty acids, leading to hepatic steatosis. Lipotoxicity from saturated fatty acids further damages hepatocytes, triggering inflammation and fibrosis progression in MASH. Diagnosing MASLD traditionally involves invasive liver biopsy, but non-invasive methods like ultrasound and transient elastography are preferred due to their safety and availability. These methods detect liver steatosis and fibrosis with reasonable accuracy, offering alternatives to biopsy despite varying sensitivity and specificity. Conclusions: MASLD as a metabolic disorder underscores its impact on public health, necessitating improved awareness and early management strategies to mitigate its progression to severe liver diseases.

1 January 2001 in The Journal of Clinical Endocrinology & Metabolism
Verified
Journal Article
Closed access
CACarlos A. Aguilar-Salinas
Carlos A. Aguilar-Salinas
EREduardo Reyes-Rodríguez
Eduardo Reyes-Rodríguez
MOMa. Luisa Ordóñez-Sánchez
Ma. Luisa Ordóñez-Sánchez
MTMarcelo Arellano Torres
Marcelo Arellano Torres
SRSalvador Ramírez-Jiménez
Salvador Ramírez-Jiménez
MTMa. Teresa Tusié-Luna
Ma. Teresa Tusié-Luna
The objective of this study was to investigate possible defects in the insulin sensitivity and/or the acute insulin response in a group of Mexican patients displaying early-onset type 2 diabetes and to evaluate the contribution of mutations in three of the genes linked to maturity-onset diabetes of the young. We studied 40 Mexican patients with an age of diagnosis between 20 and 40 yr in which the insulin sensitivity as well as the insulin secretory response were measured using the minimal model approach. A partial screening for possible mutations in 3 of the 5 genes linked to maturity-onset diabetes of the young was carried out by PCR-single strand conformation polymorphism analysis. A low insulin secretory capacity (AIRg = 68.5 +/- 5 muU/mL.min) and a near-normal insulin sensitivity (3.43 +/- 0.2 min/muU.mL x 10(4)) were found in these patients. Among this group we found two individuals carrying missense mutations in exon 4 of the hepatocyte nuclear factor-1alpha (HNF-4alpha) gene (Asp(126)-->His/Tyr and Arg(154)-->Gln, respectively) and one carrying a nonsense mutation in exon 7 of the HNF-1alpha gene (Gln(486)-->stop codon); 7.5% had positive titers for glutamic acid decarboxylase antibodies. Thirty-five percent of cases had insulin resistance; these subjects had the lipid abnormalities seen in the metabolic syndrome. A defect in insulin secretion is the hallmark in Mexican diabetic patients diagnosed between 20 and 40 yr of age. Mutations in either the HNF-1alpha or the HNF-4alpha genes are present among the individuals who develop early-onset diabetes in our population. These particular sequence changes have not been previously reported and therefore represent putative new mutations. Even in the absence of endogenous hyperinsulinemia, insulin resistance is associated with an adverse lipid profile.

6 August 2024 in Pharmaceutics
Verified
Journal Article
Open access
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MAMelchor Alpizar
Melchor Alpizar
JRJosé de Jesús Reséndiz
José de Jesús Reséndiz
EMElisa García Martínez
Elisa García Martínez
SDSANYOG DWIVEDI
SANYOG DWIVEDI
ATAlejandro Trejo
Alejandro Trejo
Enterohepatic circulation (EHC) is a complex process where drugs undergo secretion and reabsorption from the intestinal lumen multiple times, resulting in pharmacokinetic profiles with multiple peaks. The impact of EHC on area under the curve (AUC) has been a topic of extensive debate, questioning the suitability of conventional AUC estimation methods. Moreover, a universal model for accurately estimating AUC in EHC scenarios is lacking. To address this gap, we conducted a simulation study evaluating five empirical models under various sampling strategies to assess their performance in AUC estimation. Our results identify the most suitable model for EHC scenarios and underscore the critical role of meal-based sampling strategies in accurate AUC estimation. Additionally, we demonstrate that while the trapezoidal method performs comparably to other models with a large number of samples, alternative models are essential when sample numbers are limited. These findings not only illuminate how EHC influences AUC but also pave the way for the application of empirical models in real-world drug studies.

20 December 2017 in Children
Verified
Journal Article
Open access
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MAMelchor Alpizar
Melchor Alpizar
VPVanessa-Giselle Peschard
Vanessa-Giselle Peschard
FEFabiola Escalante-Araiza
Fabiola Escalante-Araiza
NANelly F Altamirano-Bustamante
Nelly F Altamirano-Bustamante
CMChiharu Murata
Chiharu Murata
ERErnesto Rodriguez-Ayala
Ernesto Rodriguez-Ayala
Overweight children and childhood obesity are a public health problem in Mexico. Obesity is traditionally assessed using body mass index (BMI), but an excess of adiposity does not necessarily reflect a high BMI. Thus, body composition indexes are a better alternative. Our objective was to generate body composition percentile curves in children from Mexico City. A total of 2026 boys and 1488 girls aged 6 to 12 years old were studied in Mexico City. Body weight, height, and BMI calculation were measured. Total body fat percentage (TBFP) was derived from the skinfold thicknesses, and fat mass (FMI) and free fat mass indexes (FFMI) were calculated. Finally, age- and gender-specifıc smoothed percentile curves were generated with Cole’s Lambda, Mu, and Sigma (LMS) method. In general, height, weight, waist circumference (WC), and TBFP were higher in boys, but FFM was higher in girls. TBFP appeared to increase significantly between ages 8 and 9 in boys (+2.9%) and between ages 10 and 11 in girls (+1.2%). In contrast, FFM% decreased noticeably between ages 8 and 9 until 12 years old in boys and girls. FMI values peaked in boys at age 12 (P97 = 14.1 kg/m2) and in girls at age 11 (P97 = 8.8 kg/m2). FFMI percentiles increase at a steady state reaching a peak at age 12 in boys and girls. Smoothed body composition percentiles showed a different pattern in boys and girls. The use of TBFP, FMI, and FFMI along with BMI provides valuable information in epidemiological, nutritional, and clinical research.