The subependymal layer in rodents: a site of structural plasticity and cell migration in the adult mammalian brain

The persistence of neurogenesis and structural plasticity was believed until recently to be restricted to lower vertebrates and songbirds. Nevertheless, it has now been ascertained that these phenomena can occur in the adult mammalian nervous system, at least in three distinct sites: the olfactory neuroepithelium of the nasal mucosa and two brain regions, namely, the hippocampal dentate gyrus and the olfactory bulb. The newly generated cells of the olfactory bulb originate from the subependymal layer, a remnant of the primitive subventricular zone persisting in the adult forebrain. Besides being characterized by high rates of cell proliferation, the subependymal layer is a site of long-distance tangential cell migration, wherein migrating cells form chains enwrapped by a particular type of astrocytes. These glial cells give rise to channels (glial tubes) that separate single chains from the surrounding mature tissue. The cellular composition and the pattern of cell migration in the mammalian subependymal layer appear to be quite different in neonatal and adult animals, changing strikingly in the postnatal period. Other features of uniqueness involve the capability of neuronal precursors to divide while undergoing migration and the presence of multipotent stem cells. Thus, the subependymal layer is an area of the adult mammalian brain endowed with a cohort of phenomena proper of neural development, persisting into (and adapted to) the fully mature nervous tissue. Such features make this system an optimal model to unravel mechanisms permitting highly dynamic structural plasticity during adulthood, in the perspective of providing strategies for possible brain repair.     

Differentiation of Trypanosoma cruzi and Trypanosoma rangeli of Colombia using minicircle hybridization tests

Although Trypanosoma rangeli is harmless for humans, it is a serious problem since it may be confused with diagnosis of Trypanosoma cruzi, the etiologic agent of Chagas disease. Both parasites overlap geographically, share antigenic protein, and are able to infect the same Triatominae vector and vertebrate host, including human. Our objective was to differentiate T. cruzi and T. rangeli isolates from Colombia based on polymerase chain reaction (PCR) amplification of the minicircles followed by appropriate hybridization tests with selected DNA probes and restriction fragment length polymorphism (RFLP) analysis. We worked with highly characterized T. cruzi and T. rangeli isolates from different biologic origins and geographic areas of Colombia, and they were analyzed by RFLP and PCR amplification of variable region of minicircles and Southern blot analysis. Our results and experimental conditions demonstrate the usefulness of PCR amplification of the minicircles followed by Southern blot analysis to differentiate T. cruzi from T. rangeli, which can be highly important to improve diagnosis of Chagas disease.     

Dynamic residential movement and depression among the World Trade Center Health Registry enrollees

Purpose

Residential instability is associated with poor mental health, but its causal inference is challenging due to time-varying exposure and confounding, and the role of changing social environments. We tested the association between frequent residential moving and depression risk among adults exposed to the 9/11 disaster.

Methods

We used four waves of survey data from the World Trade Center Health Registry. We measured residential movement and depression using geocoded annual address records and the Personal Health Questionnaire Depression Scale, respectively, for a prospective cohort of 38,495 adults. We used the longitudinal Targeted Maximum Likelihood Method to estimate depression risk by frequent residential moving and conducted causal mediation analysis to evaluate a mediating role of social environments.

Results

Most enrollees (68%) did not move in 2007–2014, and 6% moved at least once every 4 years. The remaining 26% moved less frequently (e.g., only moving in 2007–2010). Frequent moving versus no moving was associated with risk of depression in 2015–16 (RR = 1.20, 95% CI = 1.06, 1.37). Frequent residential moving—depression pathway was mediated by high social integration (OR = 0.93, 95% CI = 0.90, 0.97).

Conclusion

These findings demonstrate the importance of social networks in understanding increased risk of depression associated with housing instability.

     

Lack of association between genetic variants in the mannose-binding lectin 2 (MBL2) gene and HPV infection

Genetic variants in the immunomodulatory gene mannose-binding lectin 2 (MBL2), were associated with risk, severity, and frequency of viral infections. In a case-control setting, we investigated the association of MBL2 functional polymorphisms with Human Papillomas Virus (HPV) infection. No differences between cases (HPV⁺) and controls (HPV^–) were found in the distribution of each single genotypes or allele. Haplotype analysis did not show any difference between HPV+ and HPV^– groups. Paola Parrella and Davide Seripa contribute equally to this work.     

Cardiac troponin I in acute pericarditis

OBJECTIVES: This study was designed to investigate the prognostic value of cardiac troponin I (cTnI) in viral or idiopathic pericarditis. BACKGROUND: Idiopathic acute pericarditis has been recently reported as a possible cause of nonischemic release of cTnI. The prognostic value of this observation remains unknown. METHODS: We enrolled 118 consecutive cases (age 49.2 +/- 18.4 years; 61 men) within 24 h of symptoms onset. A highly sensitive enzymoimmunofluorometric method was used to measure cTnI (acute myocardial infarction [AMI] threshold was 1.5 ng/ml). RESULTS: A cTnI rise was detectable in 38 patients (32.2%). The following characteristics were more frequently associated with a positive cTnI test: younger age (p < 0.001), male gender (p = 0.007), ST-segment elevation (p < 0.001), and pericardial effusion (p = 0.007) at presentation. An increase beyond AMI threshold was present in nine cases (7.6%), with an associated creatine kinase-MB elevation, a release pattern similar to AMI, and echocardiographic diffuse or localized abnormal left ventricular wall motion without detectable coronary artery disease. After a mean follow-up of 24 months a similar rate of complications was found in patients with a positive or a negative cTnI test (recurrent pericarditis: 18.4 vs. 18.8%; constrictive pericarditis: 0 vs. 1.3%, for all p = NS; no cases of cardiac tamponade or residual left ventricular dysfunction were detected). CONCLUSIONS: In viral or idiopathic acute pericarditis cTnI elevation is frequently observed and commonly associated with young age, male gender, ST-segment elevation, and pericardial effusion at presentation. cTnI increase is roughly related to the extent of myocardial inflammatory involvement and, unlike acute coronary syndromes, is not a negative prognostic marker.