Men and women from the STRIDE clinical trial: An assessment of stimulant abstinence symptom severity at residential treatment entry

Background and Objectives Gender‐specific factors associated with stimulant abstinence severity were examined in a stimulant abusing or dependent residential treatment sample (N = 302). Method Bivariate statistics tested gender differences in stimulant abstinence symptoms, measured by participant‐reported experiences of early withdrawal. Multivariate linear regression examined gender and other predictors of stimulant abstinence symptom severity. Results Women compared to men reported greater stimulant abstinence symptom severity. Anxiety disorders and individual anxiety‐related abstinence symptoms accounted for this difference. African American race/ethnicity was predictive of lower stimulant abstinence severity. Discussion and Conclusions Women were more sensitive to anxiety‐related stimulant withdrawal symptoms. Scientific Significance Clinics that address anxiety‐related abstinence symptoms, which more commonly occur in women, may improve treatment outcome. (Am J Addict 2015;XX:XX –XX

DNA Instability at Chromosomal Fragile Sites in Cancer

Human chromosomal fragile sites are specific genomic regions which exhibit gaps or breaks on metaphase chromosomes following conditions of partial replication stress. Fragile sites often coincide with genes that are frequently rearranged or deleted in human cancers, with over half of cancer-specific translocations containing breakpoints within fragile sites. But until recently, little direct evidence existed linking fragile site breakage to the formation of cancer-causing chromosomal aberrations. Studies have revealed that DNA breakage at fragile sites can induce formation of RET/PTC rearrangements, and deletions within the FHIT gene, resembling those observed in human tumors. These findings demonstrate the important role of fragile sites in cancer development, suggesting that a better understanding of the molecular basis of fragile site instability is crucial to insights in carcinogenesis. It is hypothesized that under conditions of replication stress, stable secondary structures form at fragile sites and stall replication fork progress, ultimately resulting in DNA breaks. A recent study examining an FRA16B fragment confirmed the formation of secondary structure and DNA polymerase stalling within this sequence in vitro, as well as reduced replication efficiency and increased instability in human cells. Polymerase stalling during synthesis of FRA16D has also been demonstrated. The ATR DNA damage checkpoint pathway plays a critical role in maintaining stability at fragile sites. Recent findings have confirmed binding of the ATR protein to three regions of FRA3B under conditions of mild replication stress. This review will discuss recent advances made in understanding the role and mechanism of fragile sites in cancer development

Over half of breakpoints in gene pairs involved in cancer-specific recurrent translocations are mapped to human chromosomal fragile sites.

Gene rearrangements such as chromosomal translocations have been shown to contribute to cancer development. Human chromosomal fragile sites are regions of the genome especially prone to breakage, and have been implicated in various chromosome abnormalities found in cancer. However, there has been no comprehensive and quantitative examination of the location of fragile sites in relation to all chromosomal aberrations

Secondary structure formation and DNA instability at fragile site FRA16B

Human chromosomal fragile sites are specific loci that are especially susceptible to DNA breakage following conditions of partial replication stress. They often are found in genes involved in tumorigenesis and map to over half of all known cancer-specific recurrent translocation breakpoints. While their molecular basis remains elusive, most fragile DNAs contain AT-rich flexibility islands predicted to form stable secondary structures. To understand the mechanism of fragile site instability, we examined the contribution of secondary structure formation to breakage at FRA16B. Here, we show that FRA16B forms an alternative DNA structure in vitro. During replication in human cells, FRA16B exhibited reduced replication efficiency and expansions and deletions, depending on replication orientation and distance from the origin. Furthermore, the examination of a FRA16B replication fork template demonstrated that the majority of the constructs contained DNA polymerase paused within the FRA16B sequence, and among the molecules, which completed DNA synthesis, 81% of them underwent fork reversal. These results strongly suggest that the secondary-structure-forming ability of FRA16B contributes to its fragility by stalling DNA replication, and this mechanism may be shared among other fragile DNAs

The Molecular Epidemiology and Evolution of Murray Valley Encephalitis Virus: Recent Emergence of Distinct Sub-lineages of the Dominant Genotype 1

© 2015 Williams et al. Background: Recent increased activity of the mosquito-borne Murray Valley encephalitis virus (MVEV) in Australia has renewed concerns regarding its potential to spread and cause disease. Methodology/Principal Findings: To better understand the genetic relationships between earlier and more recent circulating strains, patterns of virus movement, as well as the molecular basis of MVEV evolution, complete pre-membrane (prM) and Envelope (Env) genes were sequenced from sixty-six MVEV strains from different regions of the Australasian region, isolated over a sixty year period (1951–2011). Phylogenetic analyses indicated that, of the four recognized genotypes, only G1 and G2 are contemporary. G1 viruses were dominant over the sampling period and found across the known geographic range of MVEV. Two distinct sub-lineages of G1 were observed (1A and 1B). Although G1B strains have been isolated from across mainland Australia, Australian G1A strains have not been detected outside northwest Australia. Similarly, G2 is comprised of only Western Australian isolates from mosquitoes, suggesting G1B and G2 viruses have geographic or ecological restrictions. No evidence of recombination was found and a single amino acid substitution in the Env protein (S332G) was found to be under positive selection, while several others were found to be under directional evolution. Evolutionary analyses indicated that extant genotypes of MVEV began to diverge from a common ancestor approximately 200 years ago. G2 was the first genotype to diverge, followed by G3 and G4, and finally G1, from which subtypes G1A and G1B diverged between 1964 and 1994. Conclusions/Significance: The results of this study provides new insights into the genetic diversity and evolution of MVEV. The demonstration of co-circulation of all contemporary genetic lineages of MVEV in northwestern Australia, supports the contention that this region is the enzootic focus for this virus

Over half of breakpoints in gene pairs involved in cancer-specific recurrent translocations are mapped to human chromosomal fragile sites

<p>Abstract</p> <p>Background</p> <p>Gene rearrangements such as chromosomal translocations have been shown to contribute to cancer development. Human chromosomal fragile sites are regions of the genome especially prone to breakage, and have been implicated in various chromosome abnormalities found in cancer. However, there has been no comprehensive and quantitative examination of the location of fragile sites in relation to all chromosomal aberrations.</p> <p>Results</p> <p>Using up-to-date databases containing all cancer-specific recurrent translocations, we have examined 444 unique pairs of genes involved in these translocations to determine the correlation of translocation breakpoints and fragile sites in the gene pairs. We found that over half (52%) of translocation breakpoints in at least one gene of these gene pairs are mapped to fragile sites. Among these, we examined the DNA sequences within and flanking three randomly selected pairs of translocation-prone genes, and found that they exhibit characteristic features of fragile DNA, with frequent AT-rich flexibility islands and the potential of forming highly stable secondary structures.</p> <p>Conclusion</p> <p>Our study is the first to examine gene pairs involved in all recurrent chromosomal translocations observed in tumor cells, and to correlate the location of more than half of breakpoints to positions of known fragile sites. These results provide strong evidence to support a causative role for fragile sites in the generation of cancer-specific chromosomal rearrangements.</p

Diminished Humoral and Cellular Responses to SARS-CoV-2 Vaccines in Patients with Chronic Lymphocytic Leukemia

Prior publications have demonstrated low rates of seroconversion to the SARS-CoV-2 mRNA vaccines in patients with chronic lymphocytic leukemia (CLL). In this national collaboration of 11 cancer centers around the United States, we aimed to further characterize and understand the vaccine-induced immune response, including T-cell responses and the impact of CLL therapeutics (NCT04852822). Eligible patients were enrolled into two cohorts: 1) at the time of the initial vaccination and 2) at the time of booster vaccination. Serologic response rates (anti-S) from the 210 patients in the initial vaccination cohort and 117 in the booster vaccination cohort were 56% (95% CI, 50-63%) and 68% (95% CI, 60-77%), respectively. Compared to patients not on therapy, those receiving B-cell-directed therapy were less likely to seroconvert (OR 0.27, 95% CI 0.15-0.49). Persistence of response was seen at 6 months; anti-S titers increased with administration of booster vaccinations. In the initial vaccination cohort, positive correlations were seen between quantitative serologic response and CD4 T-cell response for the Wuhan variant and to a lesser degree, for the Omicron variant (Spearman ρ = 0.45 for Wuhan, ρ = 0.25 for Omicron). In the booster vaccination cohort, positive correlations were seen between serologic response and CD4 T-cell responses for both variants (ρ = 0.58 Wuhan, ρ= 0.57 Omicron) and to a lesser degree for CD8 T-cell responses (ρ = 0.33 Wuhan, ρ = 0.22 Omicron). While no deaths from COVID-19 were reported after booster vaccinations, patients should use caution as newer variants emerge and escape vaccine-induced immunity