MRI of hippocampal volume loss in early Alzheimer's disease in relation to ApoE genotype and biomarkers

Hippocampal volume change over time, measured with MRI, has huge potential as a marker for Alzheimer's disease. The objectives of this study were: (i) to test if constant and accelerated hippocampal loss can be detected in Alzheimer's disease, mild cognitive impairment and normal ageing over short periods, e.g. 6–12 months, with MRI in the large multicentre setting of the Alzheimer's Disease Neuroimaging Initiative (ADNI); (ii) to determine the extent to which the polymorphism of the apolipoprotein E (ApoE) gene modulates hippocampal change; and (iii) to determine if rates of hippocampal loss correlate with cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease, such as the β-amyloid (Aβ1–42) and tau proteins (tau). The MRI multicentre study included 112 cognitive normal elderly individuals, 226 mild cognitive impairment and 96 Alzheimer's disease patients who all had at least three successive MRI scans, involving 47 different imaging centres. The mild cognitive impairment and Alzheimer's disease groups showed hippocampal volume loss over 6 months and accelerated loss over 1 year. Moreover, increased rates of hippocampal loss were associated with presence of the ApoE allele ɛ4 gene in Alzheimer's disease and lower CSF Aβ1–42 in mild cognitive impairment, irrespective of ApoE genotype, whereas relations with tau were only trends. The power to measure hippocampal change was improved by exploiting correlations statistically between successive MRI observations. The demonstration of considerable hippocampal loss in mild cognitive impairment and Alzheimer's disease patients over only 6 months and accelerated loss over 12 months illustrates the power of MRI to track morphological brain changes over time in a large multisite setting. Furthermore, the relations between faster hippocampal loss in the presence of ApoE allele ɛ4 and decreased CSF Aβ1–42 supports the concept that increased hippocampal loss is an indicator of Alzheimer's disease pathology and a potential marker for the efficacy of therapeutic interventions in Alzheimer's disease

Microneurosurgical Anastomoses for Cerebral Ischemia [Contents]

From jacket: The purpose of this volume is to present a series of important papers on the rapidly growing surgical field of microneurosurgical anastomoses for cerebral ischemia. It includes papers on the indications and results of microneurosurgical bypass anastomoses; on the techniques used to study patients before and after surgery, including cerebral blood flow psychometic testing, etc.; and on the basic mechanisms of cerebral ischemia studies in animals. New ideas are suggested for techniques involving increased use of the occipital arteries and the development of vein, arterial, or prosthetic grafts in place of the STA (superficial temporal artery). Also discussed are the importance of measuring blood flow in the STA where possible, and the measurement of cerebral blood flow pre- and postoperatively to monitor the results. Psychometric studies are shown to be of importance pre- and postoperatively in addition to careful neurologic evaluation

Report of the Topical Group on Top quark physics and heavy flavor production for Snowmass 2021

This report summarizes the work of the Energy Frontier Topical Group on EW Physics: Heavy flavor and top quark physics (EF03) of the 2021 Community Summer Study (Snowmass). It aims to highlight the physics potential of top-quark studies and heavy-flavor production processes (bottom and charm) at the HL-LHC and possible future hadron and lepton colliders and running scenarios

Link between Chemotactic Response to Ni²⁺ and Its Adsorption onto the Escherichia Coli Cell Surface

Bacterial chemotaxis is of medical, biological, and geological significance. Despite its importance, current chemotaxis measurements fail to account for the speciation of the chemical effector and the protonation state of the bacterial surface. We hypothesize that adsorption of Ni2+ onto the surface of Escherichia coli can influence its effective concentration and therefore influence its ability to induce a repellent response. By measuring repellent response at different pH values, the influence of Ni2+ adsorption on chemotaxis was assessed. In addition, we tested the effect of different Ni2+ chelating agents. Our data indicate that adsorption reactions influence the chemotactic response to Ni2+. We use potentiometric titration and Ni2+ adsorption experiments to develop and constrain a thermodynamic model capable of quantifying the concentration of Ni2+ at the bacteria/solution interface. Results from this model predict that the concentration of adsorbed Ni2+ is linearly proportional to the magnitude of the chemotactic response in E. coli. If adsorption is linked to chemotaxis in other cases, then chemotactic responses in realistic settings depend on a number of environmental factors such as pH, competing binding agents (e.g., aqueous organic acids, natural organic matter, mineral surfaces, etc.), and ionic strength. Our modeling approach quantifies adsorbed species on bacterial surfaces and may be used to predict the responses of different species to a variety of chemoeffectors. Our data suggest that specified changes in environmental conditions can be used to tune chemotactic responses in natural biological and geological settings