Determination of molecular forms of brain acetylcholinesterase: Technical considerations

Sucrose density centrifugation has been used to characterize the relative levels of AChE molecular forms in different parts of the brain, during development, or in various disease states. We have examined the influence of various tissue or sample storage and handling techniques on the abundance of the 4S and 10S molecular forms of AChE in rat forebrain. Our results demonstrate that freezing either a subcellular fraction or the intact tissue causes dramatic shifts in the level of the 4S and 10S molecular forms as compared to the values obtained in fresh tissue. Total AChE activity was unchanged suggesting that 4S and 10S forms are equally active and that 4S AChE is easily dissociated from 10S. These observations suggest that 4S and 10S molecular forms in brain are extremely labile and that great care should be taken when studying the factors that regulate these forms.     

DNA probe reactivity of Mycobacterium avium complex isolates from patients without AIDS

Mycobacterium avium complex isolates from 27 patients without AIDS and from 76 patients with AIDS were analyzed with the Gen-Probe Rapid Diagnostic System for Mycobacterium avium complex, and a retrospective chart review was performed to determine clinical significance of the isolates. While 87% of isolates from AIDS patients reacted only with the M. avium probe, only 37% from non-AIDS patients were M. avium probe positive (p less than 0.001). This pattern among non-AIDS patients was also observed among the 13 patients from whom isolates were considered to be clinically significant. Reactivity to both probes occurred with three isolates, two from non-AIDS patients that were not clinically significant and one from an AIDS patient. Results of further testing suggested that these represented dual infection with two coexisting strains. Awareness of the differences in DNA probe reactivity between isolates from AIDS and non-AIDS patients may influence testing strategies in the clinical laboratory.     

An essential role for an inositol polyphosphate multikinase, Ipk2, in mouse embryogenesis and second messenger production

Phospholipase C and several inositol polyphosphate kinase (IPK) activities generate a branched ensemble of inositol polyphosphate second messengers that regulate cellular signaling pathways in the nucleus and cytoplasm. Here, we report that mice deficient for Ipk2 (also known as inositol polyphosphate multikinase), an inositol trisphosphate and tetrakisphosphate 6/5/3-kinase active at several places in the inositol metabolic pathways, die around embryonic day 9.5 with multiple morphological defects, including abnormal folding of the neural tube. Metabolic analysis of Ipk2-deficient cells demonstrates that synthesis of the majority of inositol pentakisphosphate, hexakisphosphate and pyrophosphate species are disrupted, although the presence of 10% residual inositol hexakisphosphate indicates the existence of a minor alternative pathway. Agonist induced inositol tris- and bis-phosphate production and calcium release responses are present in homozygous mutant cells, indicating that the observed mouse phenotypes are a result of failure to produce higher inositol polyphosphates. Our data demonstrate that Ipk2 plays a major role in the synthesis of inositol polyphosphate messengers derived from inositol 1,4,5-trisphosphate and uncovers a role for their production in embryogenesis and normal development.     

Digital cognitive behavioral therapy for insomnia promotes later health resilience during the coronavirus disease 19 (COVID-19) pandemic

Study ObjectivesStressful life events contribute to insomnia, psychosocial functioning, and illness. Though individuals with a history of insomnia may be especially vulnerable during stressful life events, risk may be mitigated by prior intervention. This study evaluated the effect of prior digital cognitive-behavioral therapy for insomnia (dCBT-I) versus sleep education on health resilience during the COVID-19 pandemic.MethodsCOVID impact, insomnia, general- and COVID-related stress, depression, and global health were assessed in April 2020 in adults with a history of insomnia who completed a randomized controlled trial of dCBT-I (n = 102) versus sleep education control (n = 106) in 2016–2017. Regression analyses were used to evaluate the effect of intervention conditions on subsequent stress and health during the pandemic.ResultsInsomnia symptoms were significantly associated with COVID-19 related disruptions, and those who previously received dCBT-I reported less insomnia symptoms, less general stress and COVID-related cognitive intrusions, less depression, and better global health than those who received sleep education. Moreover, the odds for resurgent insomnia was 51% lower in the dCBT-I versus control condition. Similarly, odds of moderate to severe depression during COVID-19 was 57% lower in the dCBT-I condition.ConclusionsThose who received dCBT-I had increased health resilience during the COVID-19 pandemic in adults with a history of insomnia and ongoing mild to moderate mental health symptoms. These data provide evidence that dCBT-I is a powerful tool to promote mental and physical health during stressors, including the COVID-19 pandemic.Clinical Trial Registration{"type":"clinical-trial","attrs":{"text":"NCT02988375","term_id":"NCT02988375"}}NCT02988375     

Inhibition of Bacteroides fragilis on blood agar plates and reversal of inhibition by added hemin.

Bacteroides fragilis strains formed much smaller colonies on most types of blood agar plates than they did on the same media without blood. Blood inhibited strains of B. fragilis subsp. distasonis the most and B. fragilis subsp. fragilis the least. The inhibition could be eliminated by adding hemin to the blood agar. The inhibitory component of the blood was inside the erythrocytes and appeared to be the hemin-free globin of hemoglobin.