Visualization of the distribution of autophosphorylated calcium/calmodulin-dependent protein kinase II after tetanic stimulation in the CA1 area of the hippocampus

Autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) at threonine-286 produces Ca2+-independent kinase activity and has been proposed to be involved in induction of long-term potentiation by tetanic stimulation in the hippocampus. We have used an immunocytochemical method to visualize and quantify the pattern of autophosphorylation of CaMKII in hippocampal slices after tetanization of the Schaffer collateral pathway. Thirty minutes after tetanic stimulation, autophosphorylated CaM kinase II (P-CaMKII) is significantly increased in area CA1 both in apical dendrites and in pyramidal cell somas. In apical dendrites, this increase is accompanied by an equally significant increase in staining for nonphosphorylated CaM kinase II. Thus, the increase in P-CaMKII appears to be secondary to an increase in the total amount of CaMKII. In neuronal somas, however, the increase in P-CaMKII is not accompanied by an increase in the total amount of CaMKII. We suggest that tetanic stimulation of the Schaffer collateral pathway may induce new synthesis of CaMKII molecules in the apical dendrites, which contain mRNA encoding its alpha-subunit. In neuronal somas, however, tetanic stimulation appears to result in long-lasting increases in P-CaMKII independent of an increase in the total amount of CaMKII. Our findings are consistent with a role for autophosphorylation of CaMKII in the induction and/or maintenance of long-term potentiation, but they indicate that the effects of tetanus on the kinase and its activity are not confined to synapses and may involve induction of new synthesis of kinase in dendrites as well as increases in the level of autophosphorylated kinase

Blood Transfusion Errors within a Health System: A Review of Root Cause Analyses

IntroductionBlood transfusions are lifesaving treatments which require critical attention to processes and details. If processes are not followed, grievous errors can lead to sentinel events. A review of investigations completed due to reported events will show the error trends associated with systems used throughout the blood transfusion process. MethodsThis study employed root cause analyses (RCAs) within the Veterans Health Administration (VHA) to review the events leading to blood transfusion errors. Data was pulled from the RCA databases within the VA National Center for Patient Safety. The time frame was October 2014 to August 2019. A total of 53 RCAs and aggregated reviews were included in the study. These were reviewed for common themes and gaps present within processes. ResultsThe most common events fell within the categories of incorrect or delayed blood orders, incorrect or lack of patient identification, and wrong blood given. The RCA for each event was reviewed and studied. The RCAs had a crossover of multiple causes; lack of a formal process, communication barriers, and technology barriers were the most frequent. ConclusionThese RCAs express great variation between VHA facilities, such as process created, number of staff reports, and number of RCAs completed. Lack of standard practices nationwide, training barriers, and technology barriers may explain the variation of transfusion errors throughout the VHA. This study brings to light questions about standardization of transfusion protocols. Future study regarding such standardization is necessary to determine its plausibility

Methylenetetrahydrofolate reductase polymorphism 677C>T is associated with peripheral arterial disease in type 2 diabetes

BACKGROUND: Individuals with diabetes are twice as likely to develop peripheral arterial disease (PAD), the manifestation of extensive atherosclerosis throughout the lower extremities. One putative determinant of PAD is the 677C>T polymorphism in the gene encoding methylenetetrahydrofolate reductase (MTHFR), which has previously been found to associate with various diabetic complications including retinopathy, nephropathy, atherosclerosis and coronary heart disease. The objective of this study was to investigate a possible role for the MTHFR 677C>T gene polymorphism with PAD in subjects with type 2 diabetes from an isolated aboriginal Canadian population. METHODS: The 677C>T MTHFR gene polymorphism was genotyped in 138 subjects of Oji-Cree descent. Participants were selected from a community-wide survey that included PAD assessment by ankle-brachial index (ABI) measurement, and also intermittent claudication assessment by the Rose questionnaire. RESULTS: MTHFR 677T allele carriers had an increased risk of PAD with an odds ratio of 3.54 (95% CI 1.01, 12.4), P = 0.049, after adjustment for age, sex, duration of diabetes, hypertension, current smoking habits, and use of insulin or oral treatment for diabetes. None of these additional co-variables was significantly associated with PAD. No association was found between MTHFR genotype and intermittent claudication. CONCLUSION: The genetic influence of the MTHFR 677C>T genotype on diabetic PAD is modest, yet for the Oji-Cree it is a major risk factor in comparison to other traditional risk factors

Fold Lens Flux Anomalies: A Geometric Approach

We develop a new approach for studying flux anomalies in quadruply-imaged fold lens systems. We show that in the absence of substructure, microlensing, or differential absorption, the expected flux ratios of a fold pair can be tightly constrained using only geometric arguments. We apply this technique to 11 known quadruple lens systems in the radio and infrared, and compare our estimates to the Monte Carlo based results of Keeton, Gaudi, and Petters. We show that a robust estimate for a flux ratio from a smoothly varying potential can be found, and at long wavelengths those lenses deviating from from this ratio almost certainly contain significant substructure.Comment: 16 pages, including 8 figure

Cardiovascular disease risk profile and microvascular complications of diabetes: comparison of Indigenous cohorts with diabetes in Australia and Canada

<p>Abstract</p> <p>Background</p> <p>Indigenous populations of Australia and Canada experience disproportionately high rates of chronic disease. Our goal was to compare cardiovascular (CVD) risk profile and diabetes complications from three recent comprehensive studies of diabetes complications in different Indigenous populations in Australia and Canada.</p> <p>Methods</p> <p>We compared participants from three recent studies: remote Indigenous Australians (2002-2003, n = 37 known diabetes), urban Indigenous Australians (2003-2005, n = 99 known diabetes), and remote Aboriginal Canadians (2001-2002, n = 188 known diabetes).</p> <p>Results</p> <p>The three groups were similar for HbA1c, systolic BP, diabetes duration. Although leaner by body-mass-index criteria, remote Indigenous Australians displayed a more adverse CVD risk profile with respect to: waist-hip-ratio (1.03, 0.99, 0.94, remote Indigenous Australians, urban Indigenous Australians, remote Canadians, p < 0.001); HDL-cholesterol (0.82, 0.96, 1.17 mmol/L, p < 0.001); urine albumin-creatinine-ratio (10.3, 2.4, 4.5 mg/mmol); and C-reactive protein. With respect to diabetes complications, microalbuminuria (50%, 25%, 41%, p = 0.001) was more common among both remote groups than urban Indigenous Australians, but there were no differences for peripheral neuropathy, retinopathy or peripheral vascular disease.</p> <p>Conclusions</p> <p>Although there are many similarities in diabetes phenotype in Indigenous populations, this comparison demonstrates that CVD risk profiles and diabetes complications may differ among groups. Irrespective, management and intervention strategies are required from a young age in Indigenous populations and need to be designed in consultation with communities and tailored to community and individual needs.</p

Prevalence of age-related macular degeneration in old persons: Age, Gene/environment Susceptibility Reykjavik Study.

To access publisher full text version of this article. Please click on the hyperlink in Additional Links field.PURPOSE: To describe the prevalence and signs of early and late age-related macular degeneration (AMD) in an old cohort. DESIGN: Population-based cohort study. PARTICIPANTS: We included 5272 persons aged ≥66 years, randomly sampled from the Reykjavik area. METHODS: Fundus images were taken through dilated pupils using a 45-degree digital camera and graded for drusen size, type, area, increased retinal pigment, retinal pigment epithelial depigmentation, neovascular lesions, and geographic atrophy (GA) using the modified Wisconsin Age-Related Maculopathy Grading System. MAIN OUTCOME MEASURES: Age-related macular degeneration in an elderly cohort. RESULTS: The mean age of participants was 76 years. The prevalence of early AMD was 12.4% (95% confidence interval [CI], 11.0-13.9) for those aged 66 to 74 years and 36% (95% CI, 30.9-41.1) for those aged ≥85 years. The prevalence of exudative AMD was 3.3% (95% CI, 2.8-3.8). The prevalence of pure GA was 2.4% (95% CI, 2.0-2.8). The highest prevalence of late AMD was among those aged ≥85 years: 11.4% (95% CI, 8.2-14.5) for exudative AMD and 7.6% (95% CI, 4.8-10.4) for pure GA. CONCLUSIONS: Persons aged ≥85 years have a 10-fold higher prevalence of late AMD than those aged 70 to 74 years. The high prevalence of late AMD in the oldest age group and expected increase of elderly people in the western world in coming years call for improved preventive measures and novel treatments.National Institutes of Health, National Institute on Ageing and the National Eye Institute Z01-EY00401 N01-AG-1-2100 IHA Icelandic Parliament University of Icelan

Computational reconstitution of spine calcium transients from individual proteins

We have built a stochastic model in the program MCell that simulates Ca^(2+) transients in spines from the principal molecular components believed to control Ca^(2+) entry and exit. Proteins, with their kinetic models, are located within two segments of dendrites containing 88 intact spines, centered in a fully reconstructed 6 × 6 × 5 μm^3 cube of hippocampal neuropil. Protein components include AMPA- and NMDA-type glutamate receptors, L- and R-type voltage-dependent Ca^(2+) channels, Na^+/Ca^(2+) exchangers, plasma membrane Ca^(2+) ATPases, smooth endoplasmic reticulum Ca^(2+) ATPases, immobile Ca2+ buffers, and calbindin. Kinetic models for each protein were taken from published studies of the isolated proteins in vitro. For simulation of electrical stimuli, the time course of voltage changes in the dendritic spine was generated with the desired stimulus in the program NEURON. Voltage-dependent parameters were then continuously re-adjusted during simulations in MCell to reproduce the effects of the stimulus. Nine parameters of the model were optimized within realistic experimental limits by a process that compared results of simulations to published data. We find that simulations in the optimized model reproduce the timing and amplitude of Ca^(2+) transients measured experimentally in intact neurons. Thus, we demonstrate that the characteristics of individual isolated proteins determined in vitro can accurately reproduce the dynamics of experimentally measured Ca^(2+) transients in spines. The model will provide a test bed for exploring the roles of additional proteins that regulate Ca^(2+) influx into spines and for studying the behavior of protein targets in the spine that are regulated by Ca^(2+) influx

Assessing the association of the HNF1A G319S variant with C-reactive protein in Aboriginal Canadians: a population-based epidemiological study

<p>Abstract</p> <p>Background</p> <p>C-reactive protein (CRP), a biomarker of inflammation, has been associated with increased risk of developing cardiovascular disease. Common variants of the hepatocyte nuclear factor 1A (<it>HNF1A) </it>gene encoding HNF-1α have been associated with plasma CRP in predominantly European Caucasian samples. <it>HNF1A </it>might therefore have an impact on vascular disease and diabetes risk that is mediated by CRP. In an Aboriginal Canadian population, a private polymorphism, <it>HNF1A </it>G319S, was associated with increased prevalence of type 2 diabetes. However, it has not been investigated whether this association is mediated by CRP. We aimed to investigate whether CRP was mediating the association between <it>HNF1A </it>G319S and type 2 diabetes in an Aboriginal Canadian population with a high prevalence of diabetes.</p> <p>Methods</p> <p>A total of 718 individuals who participated in a diabetes prevalence and risk factor survey were included in the current analysis. Participants were genotyped for <it>HNF1A </it>G319S. Fasting plasma samples were analyzed for CRP. Fasting plasma glucose and a 75-g oral glucose tolerance test were obtained to determine type 2 diabetes.</p> <p>Results</p> <p>The prevalence rate of type 2 diabetes was 17.4% (125/718) using the 1999 World Health Organization definition and was higher among S319 allele carriers compared to G/G homozygotes (p < 0.0001). Among participants without type 2 diabetes, CRP levels were higher among G/G homozygotes (1.64 [95% confidence interval 1.35-2.00] mg/l) than in S319 carriers (1.26 [1.04-1.54] mg/l) (p = 0.009) after adjustment for age, sex, 2-h post-load glucose, waist circumference, and serum amyloid A. CRP levels were elevated among those with diabetes after similar adjustment (4.39 [95% confidence interval 3.09-6.23] and 4.44 [3.13-6.30] mg/L, respectively), and no significant difference in CRP was observed between S319 carriers and non-carriers (p = 0.95).</p> <p>Conclusions</p> <p>CRP levels were lower in S319 allele carriers of the <it>HNF1A </it>gene compared to non-carriers among individuals without diabetes, but this difference was not present among those with diabetes, who uniformly had elevated CRP levels. Therefore, while <it>HNF1A </it>appears to influence CRP concentrations in the non-diabetic state, chronic elevation of CRP is unlikely mediating the association between the <it>HNF1A </it>polymorphism and the high prevalence of type 2 diabetes in this Aboriginal population.</p

Disparate associations of a functional promoter polymorphism in PCK1 with carotid wall ultrasound traits

Background and Purpose - Cytosolic phosphoenolpyruvate carboxykinase (PEPCK; EC 4.1.1.32), encoded by PCK1, catalyzes the first committed step in gluconeogenesis. We previously showed that a -232C\u3eG promoter polymorphism within a cis-acting element required for basal and cAMP-mediated PCK1 gene transcription results in loss of negative regulation by insulin, contributing to worsened metabolic control in the context of insulin resistance. We hypothesized that this polymorphism would be associated with carotid atherosclerosis in a sample of 150 aboriginal Canadians. Methods - Dependent variables were 2 distinct carotid traits, namely intima-media thickness (IMT) assessed using B-mode ultrasound and total carotid plaque volume (TPV) assessed using 3D ultrasound. Results - Multivariate analysis showed significant but opposite associations of PCK1 genotype with these traits. Specifically, subjects with the PCK1-232G/G genotype had more carotid IMT (0.80±0.02 versus 0.73±0.03 mm; P=0.007) but less TPV (0.10±0.09 versus 0.38±0.13; P=0.03) than subjects with other genotypes. Conclusions - The findings connect the key enzyme in gluconeogenesis with atherosclerosis. The meaning of the opposing associations of PCK1 genotype with IMT and TPV is unclear; more work is required to confirm whether these might be distinct quantitative traits with different biological determinants. © 2005 American Heart Association, Inc