Gut microbiome composition may be an indicator of preclinical Alzheimer's disease

Alzheimer's disease (AD) pathology is thought to progress from normal cognition through preclinical disease and ultimately to symptomatic AD with cognitive impairment. Recent work suggests that the gut microbiome of symptomatic patients with AD has an altered taxonomic composition compared with that of healthy, cognitively normal control individuals. However, knowledge about changes in the gut microbiome before the onset of symptomatic AD is limited. In this cross-sectional study that accounted for clinical covariates and dietary intake, we compared the taxonomic composition and gut microbial function in a cohort of 164 cognitively normal individuals, 49 of whom showed biomarker evidence of early preclinical AD. Gut microbial taxonomic profiles of individuals with preclinical AD were distinct from those of individuals without evidence of preclinical AD. The change in gut microbiome composition correlated with β-amyloid (Aβ) and tau pathological biomarkers but not with biomarkers of neurodegeneration, suggesting that the gut microbiome may change early in the disease process. We identified specific gut bacterial taxa associated with preclinical AD. Inclusion of these microbiome features improved the accuracy, sensitivity, and specificity of machine learning classifiers for predicting preclinical AD status when tested on a subset of the cohort (65 of the 164 participants). Gut microbiome correlates of preclinical AD neuropathology may improve our understanding of AD etiology and may help to identify gut-derived markers of AD risk.

Cardiovascular events (CVEs) associated with tyrosine kinase inhibitor (TKI) therapy in patients with metastatic renal cell carcinoma (mRCC) at a regional cancer center

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Background: Recent studies suggest the incidence of CVEs associated with TKIs has been underestimated. Phase III trials have reported low incidences of heart failure, cardiac ischemia and hypertension. A recent observational study reported that one third of patients taking sunitinib or sorafenib experienced a cardiovascular event often without symptoms. We assessed the incidence of CVEs in mRCC patients who received TKIs at our centre. Methods: Eligible mRCC patients were identified from a mRCC database between January 2006 and November 2008. Data was retrospectively extracted including age, sex, diagnosis, histology, past cardiac history, cardiac risk factors, number and type of TKI regimens, and CVEs. A CVE was defined as unexplained death, acute coronary syndrome (ACS), heart failure, or arrhythmia requiring intervention. We also identified any new or exacerbated cases of hypertension after the start of TKI therapy, as a CVE. Results: Eighty-five eligible patients were identified. Average age was 61 years (range, 23–78), 72% were male and 80% were clear cell in origin. A total of 31 CVEs occurred in 28 patients (33%). These events occurred at a median of 5 weeks of TKI therapy (range, 1 - 64 weeks). There were 8 cases of ACS, 2 of heart failure, 2 of arrhythmia, and 3 unknown causes of death. Only 2 of these particular CVEs were associated with new or increased hypertension. There were 16 cases of hypertension alone. Those who had CVEs had a higher mean number of cardiac risk factors. They were also more likely to have an echocardiogram during treatment, and less likely to receive sorafenib following sunitinib. Conclusions: Our study suggests a lower rate of CVEs than recent studies, but the true rate may be underestimated, as routine cardiac studies were not performed in all patients. Rational surveillance strategies for patients receiving TKI therapies should be developed. Prospective trials should address predictive and prognostic factors for CVEs. [Table: see text]

[Table: see text]

The institute of medicine's "dietary reference intake" for phosphorus: a critical perspective

Two questions relevant to the safety of phosphate additives have been raised in the literature: 1) Is the dietary ratio of calcium to phosphorus clinically significant in humans? Specifically, can a high-phosphorus, low-calcium diet cause hypocalcemia and/or secondary hyperparathyroidism in humans? 2) Does the growing use of phosphate-containing food additives increase the risk of low bone density and/or fracture in humans? In 1999, the Institute of Medicine published a monograph which addressed these two questions. This article critically reviews the findings and conclusions of the Institute of Medicine in the light of recent research.

Characteristics of spatiotemporal integration in the priming and rewarding effects of medial forebrain bundle stimulation

Only the function relating the required pulse frequency to the interburst interval discriminates between the priming effect and the rewarding effect: Separating two short bursts of pulses has no effect on their combined rewarding effect, but it enhances their priming effect. There are significant nonscalar differences between animals in the number-current and charge-duration functions for priming and reward, but there are no significant differences in these functions between effects within animals. Substantially more electrical-stimulation is required to produce good priming than to produce a reward that sustains maximum possible levels of performance. These findings suggest that the priming effect is a transient excitement generated by the receipt of one or more very large rewards. The discussion elaborates a model that reconciles this hypothesis with the earlier finding that the rewarding effect may be blocked pharmacologically without blocking priming.

Yohimbine does not affect fat distribution in men

Forty-seven men with a mean age of 42 years were assigned in random, double-blind fashion to treatment with either placebo or high-dose yohimbine (peak dose, 43 mg/day). Thirty-three subjects completed the six-month program. Variables assessed throughout the study included: body weight and body mass index; total cholesterol and HDL; body fat; and fat distribution as measured both by waist-to-hip ratio and by CT scan. Treatment with yohimbine had no effect on any variable in comparison with the control group.

Pesticide poisoning surveillance through regional poison control centers

The purpose of this study is to describe pesticide exposure in the population of callers to Minnesota Regional Poison Centers. Case files from 1988 reporting pesticide exposure to humans were identified in cooperation with the Minnesota Center for Health Statistics. Data analysis was conducted by computer using SAS statistical package. Of the 1,428 case files indicating pesticide as the primary substance of exposure to Minnesota residents, a mean age of 5 years (range, one month to 85 years) was identified; 50 percent of all cases were below age 3 years. Males accounted for 1.3 times as many cases as females. Insecticide was identified in the largest percentage of case files (74 percent) followed by herbicide (12 percent), rodenticide (11 percent) and fungicide-nonmedicinal (3 percent). Ingestion was the most common route of exposure; 85 percent of all calls originated from a residence. While insecticides are still the most common types of pesticide call, herbicide has surpassed insecticide in production and sales in the US. In this study, herbicide type exposure calls present a much different picture than other pesticide types. The usefulness of poison control centers for examination of pesticide poisoning is explored. Since reporting occurs coincidental with the exposure and its associated symptoms, each pesticide poisoning report could potentially serve as a true sentinel health event.

Characteristics of spatiotemporal integration in the priming and rewarding effects of medial forebrain bundle stimulation

Only the function relating the required pulse frequency to the interburst interval discriminates between the priming effect and the rewarding effect: Separating two short bursts of pulses has no effect on their combined rewarding effect, but it enhances their priming effect. There are significant nonscalar differences between animals in the number-current and charge-duration functions for priming and reward, but there are no significant differences in these functions between effects within animals. Substantially more electrical-stimulation is required to produce good priming than to produce a reward that sustains maximum possible levels of performance. These findings suggest that the priming effect is a transient excitement generated by the receipt of one or more very large rewards. The discussion elaborates a model that reconciles this hypothesis with the earlier finding that the rewarding effect may be blocked pharmacologically without blocking priming.

Unsupervised waveform classification for multi-neuron recordings: a real-time, software-based system. I. Algorithms and implementation

We describe a new, mostly software-based device for the sorting of waveforms in an extracellular multi-neuron recording situation. The sorting algorithm is largely unattended, and, after an initial 'learning' process, works in real time. Shape comparisons are based on up to 8 time points in the waveform; these points (the reduced feature set) are chosen automatically by analyzing the current incoming data stream. A feasibility version has been implemented on a LSI-11/2 system, using FORTRAN for set-up calculations and assembler for the real-time operations. Detailed comparisons with performance of other sorting devices are presented in the companion paper.