Increased rates of CD4+ and CD8+ T lymphocyte turnover in simian immunodeficiency virus-infected macaques

Defining the rate at which T cells turn over has important implications for our understanding of T lymphocyte homeostasis and AIDS pathogenesis, yet little information on T cell turnover is available. We used the nucleoside analogue bromodeoxyuridine (BrdUrd) in combination with five-color flow cytometric analysis to evaluate T lymphocyte turnover rates in normal and simian immunodeficiency virus (SIV)-infected rhesus macaques. T cells in normal animals turned over at relatively rapid rates, with memory cells turning over more quickly than naive cells. In SIV-infected animals, the labeling and elimination rates of both CD4⁺ and CD8⁺ BrdUrd-labeled cells were increased by 2- to 3-fold as compared with normal controls. In normal and SIV-infected animals, the rates of CD4⁺ T cell BrdUrd-labeling and decay were closely correlated with those of CD8⁺ T cells. The elimination rate of BrdUrd-labeled cells was accelerated in both naive and memory T lymphocytes in SIV-infected animals. Our results provide direct evidence for increased rates of both CD4⁺ and CD8⁺ T cell turnover in AIDS virus infection and have important implications for our understanding of T cell homeostasis and the mechanisms responsible for CD4⁺ T cell depletion in AIDS.     

The European Prevalence of Resistance Associated Substitutions among Direct Acting Antiviral Failures

Background: Approximately 71 million people are still in need of direct-acting antiviral agents (DAAs). To achieve the World Health Organization Hepatitis C elimination goals, insight into the prevalence and influence of resistance associated substitutions (RAS) is of importance. Collaboration is key since DAA failure is rare and real-life data are scattered. We have established a European collaboration, HepCare, to perform in-depth analysis regarding RAS prevalence, patterns, and multiclass occurrence. Methods: Data were extracted from the HepCare cohort of patients who previously failed DAA therapy. Geno—and subtypes were provided by submitters and mostly based on in-house assays. They were reassessed using the Comet HCV subtyping tool. We considered RAS to be relevant if they were associated with DAA failure in vivo previously reported in literature. Results: We analyzed 938 patients who failed DAA therapy from ten different European countries. There were 239 genotypes (GT) 1a, 380 GT1b, 19 GT2c, 205 GT3a, 14 GT4a, and 68 GT4d infections. Several unusual subtypes (n = 15) (GT1b/g/l, GT3b, GT4k/n/r/t) were present. RAS appeared in over 80% of failures and over a quarter had three or more RAS. Multiclass RAS varied over target region and genotype between 0–48%. RAS patterns such as the Q30R + L31M and Q30R + Y93H in GT1a, the L31V + Y93H and L31V + Y93H for GT1b, and A30K + L31M and A30K/V + Y93H for GT3a all occurred with a prevalence below 5%. Conclusion: RAS occur frequently after DAA failures and follow a specific genotype and drug related pattern. Interpretation of the influence of RAS on retreatment is challenging due to various patterns, patients’ characteristics, and previous treatment history. Moving towards HCV elimination, an ongoing resistance surveillance is essential to track the presence of RAS, RAS patterns and gather data for a re-treatment algorithm.     

A 7-Tesla MRI study of the periaqueductal gray: resting state and task activation under threat

The periaqueductal gray (PAG) is a region of the midbrain implicated in a variety of behaviors including defensive responses to threat. Despite the wealth of knowledge pertaining to the differential functional roles of the PAG columns in nonhuman and human research, the basic functional connectivity of the PAG at rest has not been well characterized. Therefore, the current study utilized 7-Tesla magnetic resonance imaging (MRI) to characterize PAG functional connectivity at rest and task activation under uncertain threat. A sample of 53 neurologically healthy undergraduate participants (M_age = 22.2, s.d._age = 3.62) underwent structural and resting state functional MRI scans. Supporting previous work, voxel-wise analyses showed that the PAG is functionally connected to emotion regulation and fear networks. The comparison of functional connectivity of PAG columns did not reveal any significant differences. Thirty-five participants from the same sample also completed an uncertain threat task with blocks of three conditions—no shock, predictable shock and unpredictable shock. There were no robust activity differences within the PAG columns or the whole PAG across conditions although there was differential activity at the voxel level in the PAG and in other regions theoretically relevant to uncertain threat. Results of this study elucidate PAG connectivity at rest and activation in response to uncertain threat.     

Singleton exome sequencing of 90 fetuses with ultrasound anomalies revealing novel disease-causing variants and genotype–phenotype correlations

Exome sequencing has been increasingly implemented in prenatal genetic testing for fetuses with morphological abnormalities but normal rapid aneuploidy detection and microarray analysis. We present a retrospective study of 90 fetuses with different abnormal ultrasound findings, in which we employed the singleton exome sequencing (sES; 75 fetuses) or to a lesser extent (15 fetuses) a multigene panel analysis of 6713 genes as a primary tool for the detection of monogenic diseases. The detection rate of pathogenic or likely pathogenic variants in this study was 34.4%. The highest diagnostic rate of 56% was in fetuses with multiple anomalies, followed by cases with skeletal or renal abnormalities (diagnostic rate of 50%, respectively). We report 20 novel disease-causing variants in different known disease-associated genes and new genotype–phenotype associations for the genes KMT2D, MN1, CDK10, and EXOC3L2. Based on our data, we postulate that sES of fetal index cases with a concurrent sampling of parental probes for targeted testing of the origin of detected fetal variants could be a suitable tool to obtain reliable and rapid prenatal results, particularly in situations where a trio analysis is not possible.Subject terms: Genetics research, Disease genetics     

Primary primitive neuroectodermal tumor of the spinal cord: case report and review of the literature.

We present the clinical, radiological, and pathological features of a primary primitive neuroectodermal tumor (PNET) that occurred in the thoracic spinal cord of a 69-year-old man. Magnetic resonance imaging (MRI) demonstrated on T1-weighted images a 2x1x5 cm isointense intraspinal mass with homogeneous contrast enhancement extending from the C7 to the Th3 level. There was no clinical or radiological evidence for the existence of an intracranial tumor. Histological examination revealed a small round cell tumor with rosette formation and immunohistochemical characteristics of a PNET. The patient is the oldest among the 20 cases with this rare spinal cord neoplasm reported so far in the literature; the previously published cases are briefly reviewed.     

Dose dependent neuroprotection of the noble gas argon after cardiac arrest in rats is not mediated by KATP—Channel opening

Purpose

Argon at a dosage of 70% is neuroprotective when given 1 h after cardiac arrest (CA) in rats. In a rodent model, we investigated if the neuroprotective effects of argon are dose dependent and mediated by adenosine triphosphate dependent potassium (K_ATP) channels.

Methods

Forty-seven male Sprague-Dawley rats were subjected to 7 min of CA and 3 min of cardiopulmonary resuscitation (CPR). In protocol I animals were randomized to receive either 70% or 40% argon ventilation 1 h after successful CPR or no argon-treatment. Animals of the second protocol also received 1 h of 70% argon ventilation or no argon treatment but were randomized to a group receiving the K_ATP channel blocker 5-hydroxydecanoate (5-HD). For all animals a neurological deficit score (NDS) was calculated daily for seven days following the experiment before the animals were killed and the brains harvested for histopathological analyses.

Results

All animals survived. Control animals exhibited severe neurologic dysfunction at all points in time as measured with the NDS. Argon treated animals showed significant improvements in the NDS through all postoperative days in a dose dependent fashion. This was paralleled by a significant reduction in the neuronal damage index in the neocortex and the hippocampal CA 3/4 region. Administration of 5-HD neither abolished the positive effects on functional recovery nor on histopathologic changes observed in the argon group.

Conclusion

Our study demonstrates a dose dependent neuroprotective effect of argon administration in this rodent model, which is not mediated via ATP dependent potassium channels.