Marker chromosome genomic structure and temporal origin implicate a chromoanasynthesis event in a family with pleiotropic psychiatric phenotypes

Small supernumerary marker chromosomes (sSMC) are chromosomal fragments difficult to characterize genomically. Here, we detail a proband with schizoaffective disorder and a mother with bipolar disorder with psychotic features who present with a marker chromosome that segregates with disease. We explored the architecture of this marker and investigated its temporal origin. Array comparative genomic hybridization (aCGH) analysis revealed three duplications and three triplications that spanned the short arm of chromosome 9, suggestive of a chromoanasynthesis‐like event. Segregation of marker genotypes, phased using sSMC mosaicism in the mother, provided evidence that it was generated during a germline‐level event in the proband's maternal grandmother. Whole‐genome sequencing (WGS) was performed to resolve the structure and junctions of the chromosomal fragments, revealing further complexities. While structural variations have been previously associated with neuropsychiatric disorders and marker chromosomes, here we detail the precise architecture, human life‐cycle genesis, and propose a DNA replicative/repair mechanism underlying formation.     

PCR-based diagnosis of acute and chronic cutaneous leishmaniasis caused by Leishmania (Viannia)

We evaluated PCR methods for diagnosis of acute and chronic cutaneous leishmaniasis (CL) in an area of Colombia where Leishmania (Viannia) is endemic. The PCR method specifically amplified whole linearized minicircle kinetoplast DNA (kDNA) of the Leishmania subgenus Viannia from biopsy lysates. PCR products were detected in agarose gels. For 255 acute cases, this PCR method had greater sensitivity (75.7%) than each conventional method, i.e., microscopic examination of Giemsa-stained lesion scraping (46.7%), biopsy culture (55.3%), aspirate culture (46.3%), and the conventional methods combined (70.2%). Among 44 cases of chronic CL, amplification of biopsy DNA was more sensitive (45.5%) than the individual (4.5 to 27.7%) and combined (27.3%) conventional methods. The detection of kDNA in biopsies from chronic lesions was enhanced by a chemiluminescent dot blot hybridization, which produced a sensitivity of 65.8% when alone and 90.9% when in combination with DNA extraction of biopsy lysates (P < 0.001). Three biopsies from 84 skin lesions of other etiologies were falsely positive by PCR (specificity, 96.4%). PCR detected kDNA more frequently in biopsies (detection level, 83.9%) than in aspirates (74.7%) from 103 cases of acute CL. Among aspirates from 53 chronic cases of CL, the alternative methods, DNA extraction and hybridization, increased sensitivity from 41.5 to 56.6% (P > 0.05). This enhanced PCR method in chronic biopsies was so much more sensitive than conventional methods that it should be considered the preferred diagnostic method for chronic CL. These findings support the appropriate incorporation of PCR into diagnostic strategies for cutaneous leishmaniasis.     

RSA fluctuation in major depressive disorder

Cardiac vagal control, as measured by indices of respiratory sinus arrhythmia (RSA), has been investigated as a marker of impaired self-regulation in mental disorders, including depression. Past work in depressed samples has focused on deficits in resting RSA levels, with mixed results. This study tested the hypothesis that depression involves abnormal RSA fluctuation. RSA was measured in depressed and healthy control participants during rest and during two reactivity tasks, each followed by a recovery period. Relative to controls, depressed persons exhibited lower resting RSA levels as well as less RSA fluctuation, primarily evidenced by a lack of task-related vagal suppression. Group differences in RSA fluctuation were not accounted for by differences in physical health or respiration, whereas group differences in resting RSA level did not survive covariate analyses. Depression may involve multiple deficits in cardiac vagal control.     

Survival and Implantation of Escherichia coli in the Intestinal Tract

Preliminary experiments established that a 0.5-ml inoculum that is introduced directly into the stomach of mice was cleared rapidly into the small intestine. Bicarbonate buffer, but not skim milk, protected such an inoculum from stomach acid until at least 90% of it had entered the small intestine. Passage and survival of various Escherichia coli strains through the mouse gut were tested by introducing a buffered bacterial inoculum directly into the stomach, together with the following two intestinal tracers: Cr(51)Cl(3) and spores of a thermophilic Bacillus sp. Quantitative recovery of excreted bacteria was accomplished by collecting the feces overnight in a refrigerated cage pan. The data show that wild-type E. coli strains and E. coli K-12 are excreted rapidly (98 to 100% within 18 h) in the feces without overall multiplication or death. E. coli varkappa1776 and DP50supF, i.e., strains certified for recombinant DNA experiments underwent rapid death in vivo, such that their excretion in the feces was reduced to approximately 1.1 and 4.7% of the inoculum, respectively. The acidity of the stomach had little bactericidal effect on the E. coli K-12 strain tested, but significantly reduced the survival of more acidsensitive bacteria (Vibrio cholerae) under these conditions. Long-term implantation of E. coli strains into continuous-flow cultures of mouse cecal flora or into conventional mice was difficult to accomplish. In contrast, when the E. coli strain was first inoculated into sterile continuous-flow cultures or into germfree mice, which were subsequently associated with conventional mouse cecal flora, the E. coli strains persisted in a large proportion of the animals at levels resembling E. coli populations in conventional mice. Metabolic adaptation contributed only partially to the success of an E. coli inoculum that was introduced first. A mathematical model is described which explains this phenomenon on the basis of competition for adhesion sites in which an advantage accrues to the bacterium which occupies those sites first. The mathematical model predicts that two or more bacterial strains that compete in the gut for the same limiting nutrient can coexist, if the metabolically less efficient strains have specific adhesion sites available. The specific rate constant of E. coli growth in monoassociated gnotobiotic mice was 2.0 h(-1), whereas the excretion rate in conventional animals was -0.23 h(-1). Consequently, limitation of growth must be regarded as the primary mechanism controlling bacterial populations in the large intestine. The beginnings of a general hypothesis of the ecology of the large intestine are proposed, in which the effects of the competitive metabolic interactions described earlier are modified by the effects of bacterial association with the intestinal wall.     

A systematic review of the methodological quality of economic evaluations in genetic screening and testing for monogenic disorders

PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.     

Detection of Chronic Wasting Disease in the Lymph Nodes of Free-Ranging Cervids by Real-Time Quaking-Induced Conversion

Chronic wasting disease (CWD), a transmissible spongiform encephalopathy of deer, elk, and moose, is the only prion disease affecting free-ranging animals. Since the disease was first identified in northern Colorado and southern Wyoming in 1967, new epidemic foci of the disease have been identified in 20 additional states, as well as two Canadian provinces and the Republic of South Korea. Identification of CWD-affected animals currently requires postmortem analysis of brain or lymphoid tissues using immunohistochemistry (IHC) or an enzyme-linked immunosorbent assay (ELISA), with no practical way to evaluate potential strain types or to investigate the epidemiology of existing or novel foci of disease. Using a standardized real-time (RT)-quaking-induced conversion (QuIC) assay, a seeded amplification assay employing recombinant prion protein as a conversion substrate and thioflavin T (ThT) as an amyloid-binding fluorophore, we analyzed, in a blinded manner, 1,243 retropharyngeal lymph node samples from white-tailed deer, mule deer, and moose, collected in the field from areas with current or historic CWD endemicity. RT-QuIC results were then compared with those obtained by conventional IHC and ELISA, and amplification metrics using ThT and thioflavin S were examined in relation to the clinical history of the sampled deer. The results indicate that RT-QuIC is useful for both identifying CWD-infected animals and facilitating epidemiological studies in areas in which CWD is endemic or not endemic.     

Racial and ethnic disparities in influenza vaccination among elderly adults

Objectives: To examine whether access to care factors account for racial/ethnic disparities in influenza vaccination among elderly adults in the United States.
Design: Indicators of access to care (predisposing, enabling, environmental/system, and health need) derived from Andersen's behavioral model were identified in the National Health Interview Survey questionnaire. The relationship of these indicators to influenza vaccination and race/ethnicity was assessed with multiple logistic regression models.
Main Results: Significant differences in vaccination were observed between non-Hispanic (NH) whites (66%) and Hispanics (50%, P <.001) and between NH whites (66%) and NH blacks (46%, P <.001). Controlling for predisposing and enabling access to care indicators, education, marital status, regular source of care, and number of doctor visits, reduced the prevalence odds ratios (POR) comparing Hispanics to non-Hispanic whites from 1.89 to 1.27. For NH blacks, controlling for access to care indicators changed the POR only from 2.24 (95% CI, 1.9 to 2.7) to 1.93 (95% CI, 1.6 to 2.4).
Conclusions: This study confirmed the existence of sizable racial/ethnic differences in influenza vaccination among elderly adults. These disparities were only partially explained by differences in indicators of access to care, especially among non-Hispanic blacks for whom large disparities remained. Factors not available in the National Health Interview Survey, such as patient attitudes and provider performance, should be investigated as possible explanations for the racial/ethnic disparity in influenza vaccination among non-Hispanic blacks.     

“It Got Likes,But I Don’t Think People Understood”: A Qualitative Study of Adolescent Experiences Discussing Type 1 Diabetes on Social Media

Background:The majority of adolescents with type 1 diabetes (T1D) integrate social media engagement into their daily lives. The aim of this study was to explore adolescents’ experiences and perspectives discussing their T1D on social media.Methods:Semi-structured interviews with adolescents with T1D were conducted in person and via telephone. Questions focused on the participant’s experiences utilizing social media to discuss T1D and factors that informed the nature of T1D-related social media engagement. Open coding and thematic content analysis were used to identify emergent themes that aligned with accepted domains of social media affordances.Results:Participants included 35 adolescents with T1D. Adolescents’ experiences related to discussing T1D on social media aligned with four affordances of social media: identity, cognitive, emotional, and social. The identity affordances of social media platforms allowed adolescents to curate online personas that selectively included their diagnosis of T1D, while managing the potential negative emotional and social implications linked to the stigma of T1D. Adolescents who decided to discuss T1D on social media leveraged cognitive affordances by providing and receiving diabetes management advice, emotional affordances by obtaining affirmation from peers, and social affordances by extending their network to include other individuals with T1D.Conclusions:Adolescents with T1D flexibly leverage the affordances offered by social media to access emotional support, information, and identity affirmation resources while navigating stigma-based social consequences. Our findings highlight the value of developing tools to support adolescents with T1D in comfortably discussing and receiving appropriate support about T1D on social media.