Comparing the evolutionary dynamics of predominant SARS-CoV-2 virus lineages co-circulating in Mexico.

Over 200 different SARS-CoV-2 lineages have been observed in Mexico by November 2021. To investigate lineage replacement dynamics, we applied a phylodynamic approach and explored the evolutionary trajectories of five dominant lineages that circulated during the first year of local transmission. For most lineages, peaks in sampling frequencies coincided with different epidemiological waves of infection in Mexico. Lineages B.1.1.222 and B.1.1.519 exhibited similar dynamics, constituting clades that likely originated in Mexico and persisted for >12 months. Lineages B.1.1.7, P.1 and B.1.617.2 also displayed similar dynamics, characterized by multiple introduction events leading to a few successful extended local transmission chains that persisted for several months. For the largest B.1.617.2 clades, we further explored viral lineage movements across Mexico. Many clades were located within the south region of the country, suggesting that this area played a key role in the spread of SARS-CoV-2 in Mexico.

Intussusception due to intramural jejunal splenosis.

Splenosis is defined as the growth of ectopic splenic tissue, due to its direct seeding, usually seen after traumatic or surgical procedures to the spleen. It often occurs on highly vascularized surfaces such as the omentum or the mesentery, and grows in sessile form, supplied by adjacent vessels. Intestinal splenosis with endoluminal extension is extremely rare. We present a case of intestinal splenosis with endoluminal growth in a 14-year-old boy that provoked a small bowel intussusception requiring surgical resolution.

Evaluation of pectus excavatum indexes during standard cardiac magnetic resonance: Potential for single preoperative tool.

PURPOSE: Preoperative assessment of patients with pectus excavatum (PE) demands evaluation of malformation indexes, generally with chest computed tomography (CT). In addition, assessment of the cardiac impact of sternal depression has become a rule in high referral centers, thus requiring two independent imaging modalities and use ionizing radiation in a very young population. The objective of this study was to explore the agreement between chest CT and standard cardiac MR (CMR) for the evaluation of chest wall malformation indexes. METHODS: We included consecutive patients with PE referred to undergo chest CT and CMR to establish surgical candidacy and/or to define treatment strategies. Both CT and CMR were performed at full-expiration. In both modalities, the Haller index (HI) and the Correction index (CI) were calculated by two independent observers. In CMR, only scout images were used. Agreement was evaluated using intra-class correlation coefficients (ICC). RESULTS: Fifty patients comprised the study population (median age 19.0 years) and underwent chest CT and CMR within the same month. CMR assessment of chest malformation indexes was reproducible, with a very good inter-observer agreement for HI [ICC 0.93 (0.88-0.96), p < 0.0001] and CI [ICC 0.91 (0.83-0.95), p < 0.0001]. CMR also had a very good agreement with chest CT for HI [ICC 0.90 (0.82-0.94), p < 0.0001] and CI measurements [ICC 0.93 (95% CI 0.88-0.96), p < 0.0001]. CONCLUSIONS: We demonstrated an excellent agreement between chest CT and standard CMR for the assessment of chest wall malformations, thus potentially enabling preoperative assessment of PE severity and cardiac involvement with a single diagnostic tool.

Interspecific variation in the physiological and reproductive parameters of porcelain crabs from the Southeastern Pacific coast: potential adaptation in contrasting marine environments.

Porcelain crabs inhabit from upper intertidal to subtidal habitats. These environments are characterized by highly variable environmental conditions, which subject species found in these habitats to stress. In this study, we compared reproductive traits of mothers [i.e. fecundity, reproductive output (RO), dry weight, organic matter] and physiological parameters of their offspring (i.e. wet weight, water content, dry weight, organic matter, lactate content of embryos) of three species of porcelain crabs that inhabit the Southeastern Pacific: Petrolisthes laevigatus (upper intertidal); P. violaceus (low intertidal); Allopetrolisthes punctatus (subtidal). Overall, female P. laevigatus had lower fecundity (802 ± 115 vs. 4181 ± 1097 embryos) and amount of organic matter in their embryo masses (0.053 ± 0.006 vs. 0.27 ± 0.025 g) but higher RO values (1.34 ± 0.34 vs. 0.20 ± 0.07) than Allopetrolisthes punctatus. In addition, P. laevigatus embryos had higher organic matter content (81.09 ± 28.8 vs. 64.54 ± 6.1 µg), higher water content (188.6 ± 91.9 vs. 152.4 ± 30.8 µL) and higher lactate content (0.26 ± 0.04% vs. 0.07 ± 0.01% dry weight) than that found in A. punctatus embryos. Furthermore, females and embryos of P. violaceus showed low values and similar to those observed in P. laevigatus. As a potential strategy to increase survival of the offspring, P. laevigatus seems to invest a large portion of its energy in production of high quality embryos, despite costs to fecundity. This study reveals that porcelain crabs have physiological adaptations during their ontogeny that allow them to survive in fluctuating environments.

Exaggerated Interventricular Dependence Among Patients With Pectus Excavatum: Combined Assessment With Cardiac MRI and Chest CT.

OBJECTIVE: We sought to explore whether patients with pectus excavatum have exaggerated interventricular dependence and to evaluate the impact of the malformation severity (assessed on CT) on both anatomic and functional cardiac parameters (assessed on cardiac MRI). SUBJECTS AND METHODS: The current study involved consecutive patients with a diagnosis of pectus excavatum who were referred to undergo cardiac MRI and chest CT to establish surgical candidacy or to define treatment strategies. RESULTS: Sixty-two patients with pectus excavatum underwent cardiac MRI and chest CT. Fifty (81%) patients were male, and the median age was 17.5 years (range, 14.0-23.0 years). Forty-seven (76%) patients had evidence of right ventricular compression. The left ventricle showed a significantly decreased end-diastolic volume (inspiration vs expiration: 70.4 ± 11.6 vs 76.1 ± 13.7 mL/m2, respectively; p = 0.01) and a significantly higher eccentricity index (1.52 ± 0.2 vs 1.20 ± 0.1, p < 0.0001) during inspiration than during expiration. The median respiratory-related septal excursion was 8.1% (interquartile range, 5.1-11.7%). Patients with pericardial effusion showed a significantly higher pectus excavatum severity index than patients without pericardial effusion (6.3 ± 3.4 vs 4.4 ± 1.3, respectively; p = 0.003). Patients with a relative septal excursion equal to or larger than 11.8% showed a significantly higher pectus excavatum severity index than patients with a relative septal excursion of less than 11.8% (6.3 ± 2.6 vs 4.7 ± 2.4, respectively; p = 0.05). CONCLUSION: In this study, patients with pectus excavatum showed significant alterations of cardiac morphology and function that were related to the deformation severity and that manifest as an exaggerated interventricular dependence.