Biology subjects

Martinez, R. M.

Publications and source records attributed to Martinez, R. M..

2 recordsLinked to original sources

bioRxiv2026

Standardisation Challenges in ELISA-Based Quantification of Equine Chorionic Gonadotropin (eCG/PMSG)

Equine chorionic gonadotropin (eCG/PMSG) is widely used for female-cycle synchronization and estrus induction in livestock and in biomedical research, where reliable quantitative assessment is increasingly important. However, its structural and glycosylation heterogeneity complicates antibody-based measurement and assay standardization. This Technical Note evaluated six commercially available quantitative PMSG ELISA kits representing three distinct analytical profile groups. Kit-provided calibration standards were characterized by Western blotting, Coomassie staining, and LC-MS/MS, while quantitative performance was assessed using serial dilutions of two commercial PMSG preparations. DRG, Creative Diagnostics, and Demeditec showed similar calibration-standard profiles and concentration-dependent responses, although measured concentrations were consistently below nominal values. Biomatik and MyBiosource displayed closely related analytical profiles but little meaningful concentration-dependent response, whereas Krishgen measurements remained within a narrow range despite changes in nominal PMSG input. The calibration standards differed substantially in protein composition, and no eCG-derived peptides were identified by LC-MS/MS under the conditions used. These findings demonstrate that quantitative results obtained with commercially available PMSG ELISAs are not necessarily comparable and may be strongly influenced by calibration-material composition, assay format, and matrix effects. The findings highlight the limitations of current quantitative PMSG assays and the need for a well-characterized, commutable reference material, together with assay-specific validation of dilution parallelism and analyte recovery, to improve the reliability and comparability of eCG/PMSG measurements.

biochemistry↗

bioRxiv2020

Unmasking Anxiety in Autism: Explicit and Implicit Threatening Face Stimuli Dissociate Amygdala-centered Functional Connectivity

BackgroundAnxiety is the most prevalent comorbidity in individuals diagnosed with autism spectrum disorder (ASD). Amygdala reactivity to explicit and implicit threat processing is predictive of anxiety-related symptomatology. The neural mechanisms underlying the link between anxiety and ASD remains elusive. MethodsIn this fMRI study, we recruited young adults with ASD (N = 31) and matched them with controls, then proceeded to assess their autistic and anxiety traits by the use of the Autism-Spectrum Quotient (AQ) and the State-Trait Anxiety Inventory (STAI-S), respectively; and scanned their hemodynamic responses, including amygdala, in response to explicit and implicit (backwardly masked) perception of threatening faces. ResultsAs compared to controls, the amygdala reactivity in ASD subjects was significantly lower to explicit threat, but comparable for implicit threat. The correlations of the amygdala reactivity with the AQ and STAI-S were dissociated depending on threat processing (explicit or implicit). Furthermore, the amygdala in ASD relative to controls had a more negative functional connectivity with the superior parietal cortex, fusiform gyrus, and hippocampus for explicit threat, whereas a more positive connectivity with the medial prefrontal cortex, temporal pole, and hippocampus for implicit threat. ConclusionIn ASD, the transmission of socially relevant information along dorsal and ventral neural pathways centered on the amygdala is dissociated depending on explicit and implicit threat processing. This dissociation, ascribed to their failure to compromise pre-existing hyperarousal, might contribute to anxiety in ASD.

neuroscience↗