Altered lymphocyte catecholamine reactivity in mice subjected to chronic mild stress

There is considerable evidence that the sympathetic nervous system influences the immune response via activation and modulation of beta(2)-adrenergic receptors (beta(2)R). Furthermore, it has been suggested that stress has effects on the sympathetic nervous system. In the present study, we analyzed the influence of catecholamines on the reactivity of lymphocytes from mice exposed to a chronic mild stress (CMS) model of depression (CMS-animals). The effects of the CMS treatment on catecholamine and corticosterone levels and on beta(2)R lymphoid expression were also assessed. For this purpose, animals were subjected to CMS for 8 weeks. Results showed that catecholamines (epinephrine and norepinephrine) exert an inhibitory effect on mitogen-induced normal T-cell proliferation and a stimulatory effect on normal B-cell proliferation in response to selective B lymphocyte mitogens. Specific beta- and beta(2)-antagonists abolished these effects. Lymphocytes from mice subjected to CMS had an increased response to catecholamine-mediated inhibition or enhancement of proliferation in T and B cells, respectively. Moreover, a significant increase in beta(2)R density was observed in animals under CMS compared to normal animals. This was accompanied by an increment in cyclic AMP production after beta-adrenergic stimulation. On the other hand, neither catecholamine levels, determined in both urine and spleen samples, nor serum corticosterone levels showed significant variation between normal and CMS-animals. These findings demonstrate that chronic stress is associated with an increased sympathetic influence on the immune response and may suggest a mechanism through which chronic stress alters immunity.     

Reference Gene Selection for RT-qPCR Analysis in Maize Kernels Inoculated with Aspergillus flavus

Resistance against infection by the fungus Aspergillus flavus Link in commercial maize (Zea mays L.) is the topic of many studies, but few studies have investigated the effects of A. flavus infection on gene expression levels in ear kernels. A crucial component of gene expression profiling by RT-qPCR is having a reliable set of reference genes that show relatively constant expression across the treatments and phenotypes under study. Currently, however, there is no published information on reference genes suitable for measuring changes in kernel gene expression levels after infection with A. flavus. Thus, in this study, six candidate reference genes (ACT1, β-Tub2, eIF4A2, TATA, EFIα, and GAPDH) were evaluated and ranked according to their expression stability. The genes were amplified from first-strand cDNA samples synthesized from kernels of two susceptible and two resistant maize lines that were either inoculated with A. flavus or water or not inoculated. Three software packages were used to calculate and rank the stability of expression for these genesgeNorm, NormFinder, and BestKeeper. The analysis revealed that the most stable genes to normalize expression levels from maize kernels responding to A. flavus inoculation and wounding were ACT1, EFIα, and eIF4A2.     

Early gadolinium enhancement in hypertrophic cardiomyopathy: a potential premature marker of myocardial damage

Early gadolinium enhancement (EGE), one CMR diagnostic criteria in acute myocarditis, has been related with hyperemia and capillary leakage. The value of EGE in hypertrophic cardiomyopathy (HCM) remains unknown. Our aim was to determine the prevalence of EGE in patients with HCM, and its relation with late gadolinium enhancement (LGE). The association of EGE with morphological and clinical parameters was also evaluated. Sixty consecutive patients with HCM and CMR from our center were included. All the clinical and complementary test information was collected prospectively in our HCM clinic. Left ventricular (LV) measurements were calculated from cine sequences. EGE and LGE were quantified with a dedicated software. Clinical events were collected from medical records. A slow wash-out pattern on EGE was detected in up to 68?% of the patients, being an isolated finding without LGE in 10 (16?%). This cohort showed a greater maximal LV wall thickness (20.1?±?4 vs. 18.1?±?3.5 mm, p?=?0.010) and asymmetry ratio (1.86?±?0.42 vs. 1.62?±?0.46; p?=?0.039). The percentage of EGE/slice and the difference with the percentage LGE/slice demonstrated a significant positive correlation with the maximal LV wall thickness (Rho 0.450 and 0.386 respectively). EGE also correlated with number of segments with LVH (LV hypertrophy) and the asymmetry ratio. Neither EGE nor LGE were associated with classical risk factors, the risk score for sudden cardiac death, or with major clinical events. EGE was a frequent finding in HCM, even in absence of LGE. This phenomenon showed a positive correlation with morphological markers of disease burden.     

Discriminatory Weight of SNPs in Spike SARS-CoV-2 Variants: A Technically Rapid,Unambiguous, and Bioinformatically Validated Laboratory Approach

Background: The SARS-CoV-2 virus has assumed considerable importance during the COVID-19 pandemic. Its mutation rate is high, involving the spike (S) gene and thus there has been a rapid spread of new variants. Herein, we describe a rapid, easy, adaptable, and affordable workflow to uniquely identify all currently known variants through as few analyses. Our method only requires two conventional PCRs of the S gene and two Sanger sequencing reactions, and possibly another PCR/sequencing assay on a N gene portion to identify the B.1.160 lineage. Methods: We selected an S gene 1312 bp portion containing a set of SNPs useful for discriminating all variants. Mathematical, statistical, and bioinformatic analyses demonstrated that our choice allowed us to identify all variants even without looking for all related mutations, as some of them are shared by different variants (e.g., N501Y is found in the Alpha, Beta, and Gamma variants) whereas others, that are more informative, are unique (e.g., A57 distinctive to the Alpha variant). Results: A “weight” could be assigned to each mutation that may be present in the selected portion of the S gene. The method’s robustness was confirmed by analyzing 80 SARS-CoV-2-positive samples. Conclusions: Our workflow identified the variants without the need for whole-genome sequencing and with greater reliability than with commercial kits.     

The phenotypic spectrum of congenital Zika syndrome

In October 2015, Zika virus (ZIKV) outbreak the Brazilian Ministry of Health (MoH). In response, the Brazilian Society of Medical Genetics established a task force (SBGM‐ZETF) to study the phenotype of infants born with microcephaly due to ZIKV congenital infection and delineate the phenotypic spectrum of this newly recognized teratogen. This study was based on the clinical evaluation and neuroimaging of 83 infants born during the period from July, 2015 to March, 2016 and registered by the SBGM‐ZETF. All 83 infants had significant findings on neuroimaging consistent with ZIKV congenital infection and 12 had confirmed ZIKV IgM in CSF. A recognizable phenotype of microcephaly, anomalies of the shape of skull and redundancy of the scalp consistent with the Fetal Brain Disruption Sequence (FBDS) was present in 70% of infants, but was most often subtle. In addition, features consistent with fetal immobility, ranging from dimples (30.1%), distal hand/finger contractures (20.5%), and feet malpositions (15.7%), to generalized arthrogryposis (9.6%), were present in these infants. Some cases had milder microcephaly or even a normal head circumference (HC), and other less distinctive findings. The detailed observation of the dysmorphic and neurologic features in these infants provides insight into the mechanisms and timings of the brain disruption and the sequence of developmental anomalies that may occur after prenatal infection by the ZIKV.

     

Mitral valve regurgitation: paradoxical behavior of dobutamine stress cardiac magnetic resonance imaging

A 62-year-old woman with mitral regurgitation (MR) underwent cardiac magnetic resonance (CMR) and dobutamine stress CMR imaging, a widely used method to analyze left ventricular function and MR volumes. During dobutamine provocation at escalating doses, the left ventricular end-diastolic diameter (LVEDD) decreased, with a corresponding decrease in MR. At peak dobutamine dose, the LVEDD further decreased, with near complete relief of MR. Upon cessation of dobutamine provocation, the MR returned to predobutamine level. This case thereby demonstrates that MR may be reversible under certain conditions.     

Characterization of a variant of the SCCmec element in a bloodstream isolate of Staphylococcus intermedius

Here we report for the first time, a detailed characterization of a variant of the SCCmec element, in a methicillin-resistant Staphylococcus intermedius human isolate. S. intermedius is a coagulase-positive zoonotic microrganism, recently classified as a separate species. In routine clinical laboratory practice, the coagulase production is used as criterion of pathogenicity related to S. aureus, but S. intermedius is frequently misidentified-being mistaken for S. aureus-and consequently its real incidence underestimated. S. intermedius have been found only occasionally in human beings, and methicillin-resistance is very rare for this organism. Even if the genetic element responsible for methicillin-resistance--the mecA gene carried by diverse staphylococcal chromosomal cassettes--has been described in various staphylococcal species, the current literature doesn't report any case of S. intermedius isolate carrying SCCmec-like elements. Our study could be useful to explain the mechanism and routes of transfer of the chromosomal cassette carrying the mec complex, among staphylococci.