To understand the role of depressive symptoms in preclinical Alzheimer's disease, it is essential to define their temporal relationship to Alzheimer's proteinopathies in cognitively normal older ...adults. The study objective was to examine associations of brain amyloid beta and longitudinal measures of depression and depressive symptom clusters in a cognitively normal sample of older adults.
A total of 270 community-dwelling, cognitively normal elderly individuals underwent baseline Pittsburgh compound B (PiB) positron emission tomography (PET) measures of cortical aggregate amyloid beta and annual assessments with the 30-item Geriatric Depression Scale (GDS). The authors evaluated continuous PiB binding as a predictor of GDS score or GDS cluster, calculated as total scores and mean scores for three GDS item clusters (apathy-anhedonia, dysphoria, and anxiety-concentration), across time (1-5 years; mean=3.8 years) in separate mixed-effects models with backward elimination. Initial predictors included PiB binding, age, sex, Hollingshead score, American National Adult Reading Test (AMNART) score, apolipoprotein E ε4 status, depression history, and their interactions with time.
Higher PiB binding predicted accelerated rates of increase in GDS score over time, adjusting for depression history. Higher PiB binding also predicted steeper rates of increase for anxiety-concentration scores, adjusting for depression history and the AMNART score-by-time interaction. In a post hoc model estimating anxiety scores without concentration disturbance items, the PiB binding-by-time interaction remained significant.
Higher amyloid beta burden was associated with increasing anxious-depressive symptoms over time in cognitively normal older individuals. Prior depression history was related to higher but not worsening symptom ratings. These results suggest a direct or indirect association of elevated amyloid beta levels with worsening anxious-depressive symptoms and support the hypothesis that emerging neuropsychiatric symptoms represent an early manifestation of preclinical Alzheimer's disease.
Protein secretion through type-three secretion systems (T3SS) is critical for motility and virulence of many bacteria. Proteins are transported through an export gate containing three proteins ...(FliPQR in flagella, SctRST in virulence systems). A fourth essential T3SS protein (FlhB/SctU) functions to "switch" secretion substrate specificity once the growing hook/needle reach their determined length. Here, we present the cryo-electron microscopy structure of an export gate containing the switch protein from a Vibrio flagellar system at 3.2 Å resolution. The structure reveals that FlhB/SctU extends the helical export gate with its four predicted transmembrane helices wrapped around FliPQR/SctRST. The unusual topology of the FlhB/SctU helices creates a loop wrapped around the bottom of the closed export gate. Structure-informed mutagenesis suggests that this loop is critical in gating secretion and we propose that a series of conformational changes in the T3SS trigger opening of the gate through interactions between FlhB/SctU and FliPQR/SctRST.
This guideline is a revision of the clinical practice guideline, "Diagnosis and Management of Bronchiolitis," published by the American Academy of Pediatrics in 2006. The guideline applies to ...children from 1 through 23 months of age. Other exclusions are noted. Each key action statement indicates level of evidence, benefit-harm relationship, and level of recommendation. Key action statements are as follows:
B-cell receptor (BCR) signaling is aberrantly activated in chronic lymphocytic leukemia (CLL). Bruton tyrosine kinase (BTK) is essential to BCR signaling and in knockout mouse models its mutation has ...a relatively B cell–specific phenotype. Herein, we demonstrate that BTK protein and mRNA are significantly over expressed in CLL compared with normal B cells. Although BTK is not always constitutively active in CLL cells, BCR or CD40 signaling is accompanied by effective activation of this pathway. Using the irreversible BTK inhibitor PCI-32765, we demonstrate modest apoptosis in CLL cells that is greater than that observed in normal B cells. No influence of PCI-32765 on T-cell survival is observed. Treatment of CD40 or BCR activated CLL cells with PCI-32765 results in inhibition of BTK tyrosine phosphorylation and also effectively abrogates downstream survival pathways activated by this kinase including ERK1/2, PI3K, and NF-κB. In addition, PCI-32765 inhibits activation-induced proliferation of CLL cells in vitro, and effectively blocks survival signals provided externally to CLL cells from the microenvironment including soluble factors (CD40L, BAFF, IL-6, IL-4, and TNF-α), fibronectin engagement, and stromal cell contact. Based on these collective data, future efforts targeting BTK with the irreversible inhibitor PCI-32765 in clinical trials of CLL patients is warranted.
The causes of cognitive impairment in dementia with Lewy bodies (DLB) and Parkinson disease (PD) are multifactorial. Tau pathologic changes are commonly observed at autopsy in individuals with DLB ...and PD dementia, but their contribution to these diseases during life is unknown.
To contrast tau aggregation in DLB, cognitively impaired persons with PD (PD-impaired), cognitively normal individuals with PD (PD-normal), and healthy persons serving as control participants, and to evaluate the association between tau aggregation, amyloid deposition, and cognitive function.
This cross-sectional study was conducted from January 1, 2014, to April 28, 2016, in a tertiary care center's memory and movement disorders units. Twenty-four patients with Lewy body disease (7 DLB, 8 PD-impaired, and 9 PD-normal) underwent multimodal brain imaging, cognitive testing, and neurologic evaluation, and imaging measures were compared with those of an independently acquired group of 29 controls with minimal brain amyloid burden as measured with carbon 11-labeled Pittsburgh Compound B (11CPiB) positron emission tomography (PET).
Imaging with fluorine 18-labeled AV-1451 (18FAV-1451) (formerly known as 18FT807), 11CPiB PET, magnetic resonance imaging (MRI), neurologic examination, and detailed cognitive testing using the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating scale.
Main outcomes were differentiation of diagnostic groups on the basis of 18FAV-1451 binding, the association of 18FAV-1451 binding with 11CPiB binding, and the association of 18FAV-1451 binding with cognitive impairment. All but 3 individuals underwent amyloid imaging with 11CPiB PET. The hypotheses being tested were formulated before data collection. Mini-Mental State Examination (range, 0-30, with 30 being best) and Clinical Dementia Rating scale sum-of-boxes scale (range, 0-18, with 0 being best) were used for assessment of cognitive function.
In patients with DLB, cortical 18FAV-1451 uptake was highly variable and greater than in the controls, particularly in the inferior temporal gyrus and precuneus. Foci of increased 18FAV-1451 binding in the inferior temporal gyrus and precuneus were also evident in PD-impaired patients. Elevated cortical 18FAV-1451 binding was observed in 4 of 17 patients with Lewy body disease with low cortical 11CPiB retention. For DLB and PD-impaired patients, greater 18FAV-1451 uptake in the inferior temporal gyrus and precuneus was associated with increased cognitive impairment as measured with the MMSE and the Clinical Dementia Rating scale sum-of-boxes score.
Patients with Lewy body disease manifest a spectrum of tau pathology. Cortical aggregates of tau are common in patients with DLB and in PD-impaired patients, even in those without elevated amyloid levels. When present, tau deposition is associated with cognitive impairment. These findings support a role for tau copathology in the Lewy body diseases.
To examine neuropsychiatric and neuropsychological predictors of progression from normal to early clinical stages of Alzheimer disease (AD).
From a total sample of 559 older adults from the ...Massachusetts Alzheimer's Disease Research Center longitudinal cohort, 454 were included in the primary analysis: 283 with clinically normal cognition (CN), 115 with mild cognitive impairment (MCI), and 56 with subjective cognitive concerns (SCC) but no objective impairment, a proposed transitional group between CN and MCI. Two latent cognitive factors (memory-semantic, attention-executive) and two neuropsychiatric factors (affective, psychotic) were derived from the Alzheimer's Disease Centers' Uniform Data Set neuropsychological battery and Neuropsychiatric Inventory brief questionnaire. Factors were analyzed as predictors of time to progression to a worse diagnosis using a Cox proportional hazards regression model with backward elimination. Covariates included baseline diagnosis, gender, age, education, prior depression, antidepressant medication, symptom duration, and interaction terms.
Higher/better memory-semantic factor score predicted lower hazard of progression (hazard ratio HR = 0.4 for 1 standard deviation SD increase, p <0.0001), and higher/worse affective factor score predicted higher hazard (HR = 1.3 for one SD increase, p = 0.01). No other predictors were significant in adjusted analyses. Using diagnosis as a sole predictor of transition to MCI, the SCC diagnosis carried a fourfold risk of progression compared with CN (HR = 4.1, p <0.0001).
These results identify affective and memory-semantic factors as significant predictors of more rapid progression from normal to early stages of cognitive decline and highlight the subgroup of cognitively normal elderly with SCC as those with elevated risk of progression to MCI.
The complement system is a key component regulation influences susceptibility to age-related macular degeneration, meningitis, and kidney disease. Variation includes genomic rearrangements within the ...complement factor H-related (CFHR) locus. Elucidating the mechanism underlying these associations has been hindered by the lack of understanding of the biological role of CFHR proteins. Here we present unique structural data demonstrating that three of the CFHR proteins contain a shared dimerization motif and that this hitherto unrecognized structural property enables formation of both homodimers and heterodimers. Dimerization confers avidity for tissue-bound complement fragments and enables these proteins to efficiently compete with the physiological complement inhibitor, complement factor H (CFH), for ligand binding. Our data demonstrate that these CFHR proteins function as competitive antagonists of CFH to modulate complement activation in vivo and explain why variation in the CFHRs predisposes to disease.
Summary Background Chemoimmunotherapy has led to improved numbers of patients achieving disease response, and longer overall survival in young patients with chronic lymphocytic leukaemia; however, ...its application in elderly patients has been restricted by substantial myelosuppression and infection. We aimed to assess safety and activity of ibrutinib, an orally administered covalent inhibitor of Bruton tyrosine kinase (BTK), in treatment-naive patients aged 65 years and older with chronic lymphocytic leukaemia. Methods In our open-label phase 1b/2 trial, we enrolled previously untreated patients at clinical sites in the USA. Eligible patients were aged at least 65 years, and had symptomatic chronic lymphocytic leukaemia or small lymphocytic lymphoma requiring therapy. Patients received 28 day cycles of once-daily ibrutinib 420 mg or ibrutinib 840 mg. The 840 mg dose was discontinued after enrolment had begun because comparable activity of the doses has been shown. The primary endpoint was the safety of the dose-fixed regimen in terms of frequency and severity of adverse events for all patients who received treatment. This study is registered with ClinicalTrials.gov , number NCT01105247. Findings Between May 20, 2010, and Dec 18, 2012, we enrolled 29 patients with chronic lymphocytic leukaemia and two patients with small lymphocytic lymphoma. Median age was 71 years (range 65–84), and 23 (74%) patients were at least 70 years old. Toxicity was mainly of mild-to-moderate severity (grade 1–2). 21 (68%) patients had diarrhoea (grade 1 in 14 45% patients, grade 2 in three 10% patients, and grade 3 in four 13% patients). 15 (48%) patients developed nausea (grade 1 in 12 39% patients and grade 2 in three 10% patients). Ten (32%) patients developed fatigue (grade 1 in five 16% patients, grade 2 in four 13% patients, and grade 3 in one 3% patient). Three (10%) patients developed grade 3 infections, although no grade 4 or 5 infections occurred. One patient developed grade 3 neutropenia, and one developed grade 4 thrombocytopenia. After a median follow-up of 22·1 months (IQR 18·4–23·2), 22 (71%) of 31 patients achieved an objective response (95% CI 52·0–85·8); four patients (13%) had a complete response, one patient (3%) had a nodular partial response, and 17 (55%) patients had a partial response. Interpretation The safety and activity of ibrutinib in elderly, previously untreated patients with symptomatic chronic lymphocytic leukaemia, or small lymphocytic lymphoma is encouraging, and merits further investigation in phase 3 trials. Funding Pharmacyclics, Leukemia and Lymphoma Society, D Warren Brown Foundation, Mr and Mrs Michael Thomas, Harry Mangurian Foundation, P50 CA140158 to Prof J C Byrd MD.
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