Gac Med Mex
-
The objective of this issue is a theoretical approach to the disadvantages involved in taking the certification exams of medical specializations through serial case reports and analyzing them with the Classical Test Theory (TCT). The certification exams of medical specializations correspond to criterial summative exams with high consequences. ⋯ The violation of the fundamental assumptions of the TCT in the tests constructed through serial case reports can lead to biases or misinterpretations of the results. Due to the above, it is advisable to use other psychometric models for the analysis of this type of test, or to avoid the use of serial case reports in the certification exams of medical specialties.
-
Distraction osteogenesis is a process of induced bone generation. Various protocols have been described for the management of the latency period, distraction speed and consolidation period, with greater or lesser success. ⋯ The sequential histological study allowed to observe the appearance of cellular elements (osteocytes, osteoclasts, osteoid matrix, trabeculate, etc.) and their participation in granulation tissue, newly-formed bone and compact mature bone.
-
Humans are exposed every day to innumerable external stimuli, both environmental and microbial. Immunological memory recalls each specific stimulus and mounts a secondary response that is faster and of a larger magnitude than the primary response; this process constitutes the basis for vaccine development. ⋯ Memory T cells have an important role in the resolution of COVID-19, and they are key pillars of immunological memory. In this review, we summarize the main findings regarding anti-SARS-CoV-2 memory T cells after infection, after vaccination, and after the combination of these two events ("hybrid immunity"), and analyze how these cells can contribute to long-term protection against the infection with SARS-CoV-2 variants.
-
Comparative Study
Complications of twin pregnancy by assisted reproductive techniques compared with spontaneous.
Twin pregnancy through assisted reproduction techniques is increasing, as are the associated complications. ⋯ Twin pregnancy due to ART increases the risk of maternal and perinatal complications, which forces us to improve prenatal control with a risk approach.