bluuebunny/crossref_metadata_2025_split huggingface dataset:
HDLs and LDLs in the Brain: Characterizing the Lipid Secretome of Astrocytes
Authors: Nguyen Amanda 
Published: November 2023

Comprising up to a hundred‐fold more lipid than a typical cell, a neuron has extensive processes like dendrites and axons. The magnitude of the neuronal membrane surface area suggests the importance of the regulation of the lipids in the membrane to maintain normal neuronal function. While particles like high density lipoproteins (HDL), low density lipoproteins (LDL), and very low density lipoproteins (VLDL) normally circulate throughout the body for lipid regulation, these particles cannot pass the blood brain barrier. The brain must synthesize lipids locally in order to fulfill the biosynthetic/repair needs of the neurons. Lipid synthesis and transportation in the brain are facilitated by astrocytes, the helper glial cells of the nervous system. Astrocytes package and secrete lipids into “HDL/LDL‐like” particles, comprising a lipid core and a shell of proteins, like apolipoproteins, on the exterior. These particles function to regulate the lipid membrane of adjacent neurons, but they also vary in functionality depending on the particles' ratio of lipids to proteins (or how “LDL‐like” or “HDL‐like” the particles are). For example, apolipoprotein E (apoE) is a protein that is synthesized by astrocytes and is essential for cholesterol transportation to neurons. In Alzheimer's Disease (AD) specifically, the apoE4 polymorphism is implicated in higher AD frequency than other apoE polymorphisms because apoE4 is a weaker carrier of cholesterol than the other apoE variants. The apoE variant functionality suggests the imperative role of cholesterol homeostasis to maintain normal function in neurons. ApoE has also been shown to be the main constituent of the HDL‐like particles in the brain. Our initial studies of the lipid secretome of primary cultured mouse astrocytes revealed that the younger astrocytes secreted nearly ten‐fold less cholesterol than the older astrocytes while protein secretions between the different ages were not significantly different. These results suggest the “HDL‐like” particles are secreted more by the younger astrocytes while the “LDL‐like” particles are secreted by older astrocytes, revealing how aging plays a role in lipid homeostasis. We are continuing to isolate the lipid secretome of our primary astrocytes by using the lipid‐binding resin, Cleanascite. In order to understand the composition of these lipid particles, we are using thin layer chromatography to observe the presence of different lipids qualitatively and quantitatively.Support or Funding InformationMach Research Fellowship and Cowles Professorship
Lessons from evolutionary medicine for sepsis and critical care
Authors: Alcock Joe 
Published: November 2023

Sepsis remains a leading cause of death, causing approximately 60,000 deaths yearly. Despite hundreds of clinical trials and billions of dollars, only one agent aimed specifically at sepsis was ever approved by the FDA. It was subsequently withdrawn from the market after it was shown to be ineffective. Despite this and similar failures, researchers continue to search for therapies aimed at blocking inflammation and other physiologic changes in sepsis. These approaches have failed to improve mortality in human sepsis in part because they overlook functional adaptations and evolved tradeoffs in sepsis physiology. We have followed a series of 160 patients with severe sepsis admitted to the intensive care unit at the University of New Mexico, with the aim of predicting mortality based on initial measures of lactate, glucose, and kidney function in sepsis. Many of these parameters, e.g. blood glucose, follow similar distributions in survivors as compared to non‐survivors. Recent randomized controlled trials aimed at normalizing these parameters have generally failed to improve survival. These lines of evidence indicate that many sepsis “abnormalities” are in fact adaptive, not dysfunctional. This presentation will give examples of how evolutionary and evidence‐based medicine can work in concert to produce better outcomes in sepsis and critical care.Support or Funding InformationValente Foundation and the University of New Mexico Department of Emergency Medicine
Structural and Functional Characterization of Outer Membrane Usher Activation in Uropathogenic E. coli
Authors: Omattage Natalie , Deng Zengqin , Yuan Peng , Hultgren Scott J. 
Published: November 2023

Gram‐negative bacteria assemble extracellular fibers termed chaperone‐usher pathway (CUP) pili to adhere to host tissues and promote colonization. This has been best studied in the establishment of urinary tract infections (UTIs), which affect 60% of women in their lifetime. Uropathogenic Escherichia coli (UPEC) is the causative agent of 85% of community‐acquired UTIs. UPEC utilize the type 1 pilus, via its tip‐located FimH adhesin, to bind and adhere to mannosylated receptors on the surface of bladder epithelium. Type 1 pilus assembly is an intricate molecular process that requires the passage and polymerization of hundreds of subunits across both the inner and outer membranes of the bacterium. To accomplish this, the dedicated periplasmic chaperone, FimC, binds to and facilitates folding and maintenance of pilus subunits in a high‐energy conformation suitable for polymerization; and the outer membrane usher, FimD, serves as a multi‐domain assembly platform to catalyze subunit polymerization. Pilus assembly is initiated by the high‐affinity binding of the chaperone‐adhesin complex (FimCH) to the N‐terminal periplasmic domain of FimD. By some unknown mechanism, this binding event results in the “activation” of the usher for its catalytic activity. Usher activation results in marked rearrangements within the transmembrane and periplasmic FimD domains, but it remains unclear how chaperone‐adhesin binding to FimD triggers these conformational changes. We have conducted extensive structure‐function studies to gain insight into the molecular mechanism by which the chaperone‐adhesin primes the FimD usher for activation. Using mutagenesis and in vivo functional assays, we have identified interaction interfaces important for usher activation. We have developed systems for large‐scale expression and purification of the FimD usher and for reconstitution of pilus assembly intermediates in vitro. We are currently characterizing the structural basis for chaperone‐adhesin complex engagement of the N‐terminal domain of the FimD usher using X‐ray crystallography, single particle cryo‐electron microscopy (cryo‐EM) and small angle X‐ray scattering (SAXS) methods. Taken together, these biochemical and biophysical studies will provide unprecedented insight into how allostery primes the usher and drives pilus biogenesis. Ultimately, these studies have the potential to inform the development of innovative small molecules that block events at the outer membrane usher and prevent assembly of one of the bacterium's major virulence factors.Support or Funding InformationNSF GRFP DGE‐1143954 (NSO) and NIH R01 AI029549‐24 (SJH)
In vitro Activity of a Purified Natural Anion Channelrhodopsin
Authors: Li Hai , Sineshchekov Oleg , Wu Gang , Spudich John 
Published: November 2023

Natural anion channelrhodopsins (ACRs) recently discovered in cryptophyte algae are the most active rhodopsin channels known. They are of interest both because of their unique natural function of light‐gated chloride conductance, and their unprecedented efficiency of membrane hyperpolarization for optogenetic neuron silencing. Light‐induced currents of ACRs have been studied in HEK cells and neurons, but light‐gated channel conductance of ACRs in vitro has not been demonstrated. Here we report light‐induced chloride channel activity of a purified ACR protein reconstituted in large unilamellar vesicles (LUVs). Electron paramagnetic resonance (EPR) measurements establish that the channels are inserted uniformly ‘inside‐out’ with their cytoplasmic surface facing the medium of the LUV suspension. We show by time‐resolved flash spectroscopy that the photochemical reaction cycle of a functional purified ACR from Guillardia theta (GtACR1) in LUVs exhibits similar spectral shifts indicating similar photocycle intermediates as GtACR1 in detergent micelles. Furthermore, the photocycle rate is dependent on electric potential generated by chloride gradients in the LUVs in the same manner as in voltage‐clamped animal cells. We confirm with this system that, opposite to cation‐conducting channelrhodopsins, opening of the channel occurs prior to deprotonation of the Schiff‐base. However, the photointermediate transitions in the LUVs exhibit faster kinetics. The ACR‐incorporated LUVs provides a purified defined system amenable to EPR, optical and vibrational spectroscopy, and fluorescence resonance energy transfer measurements of structural changes of ACRs with the molecules in a demonstrably functional state.Support or Funding InformationThis work was supported by NIH grant R01GM027750 and Endowed Chair AU‐0009 from the Robert A. Welch Foundation.
Probing the structural basis of P‐glycoprotein transport of μ‐opioid receptor agonists: methadone and loperamide
Authors: Gibbs Morgan Elizabeth , Ledwitch Kaitlyn , Roberts Arthur 
Published: November 2023

P‐glycoprotein (Pgp) protects the brain from toxic insults by acting as a gatekeeper at the blood‐brain barrier. In addition to effluxing toxins, Pgp can also limit penetration of therapeutics into the brain for the treatment of central nervous system (CNS) disorders and diseases, including μ‐opioid receptor agonists that are used in pain management. Although they are structurally similar, the μ‐opioid receptor agonist loperamide (Imodium®) is effluxed out of the CNS by Pgp at four times the rate of methadone. Because of these differences, methadone and loperamide were used as model drugs to probe the mechanism of Pgp‐mediated μ‐opioid receptor agonist efflux. We hypothesize that higher Pgp‐mediated efflux rates of loperamide are the result of multiple loperamide binding to Pgp, allowing more drug to be transported per ATP hydrolyzed. We found that loperamide was a more potent activator of Pgp‐mediated ATP hydrolysis than methadone. Consistent with our hypothesis, the loperamide‐induced activation of ATP hydrolysis suggested at least two loperamide binding sites on Pgp, while methadone‐induced activation of ATP hydrolysis suggested a single methadone binding site. NMR and fluorescence were used to investigate the interactions of these drugs with the transporter and develop a structural model for transport. The saturation transfer double difference (STDD) NMR technique identified the functional groups involved in molecular recognition of Pgp and revealed that loperamide had more interactions with the transporter than methadone, which is consistent with the higher transport rate of loperamide. Acrylamide quenching of Pgp fluorescence to probe transporter conformation indicated that loperamide shifts Pgp into a conformation that promotes ATP hydrolysis and transport, while methadone shifts Pgp into an inhibitory conformation. This information combined with paramagnetic relaxation enhancement (PRE) NMR experiments and computer modelling was used to pinpoint the binding locations of loperamide and methadone on Pgp. The drug‐bound Pgp models suggest that multiple drug binding and conformational changes play a critical role in Pgp transport of this class of drugs.Support or Funding InformationThis work was funded and supported by the National Institute of Health R15 Area Grant (1R15GM107913‐01A1).
Combining Same‐Day Student Food Diaries With ASA‐24 Interviews and Coding to Accurately Assess the in‐School Food Consumption of 4th to 6th Graders
Authors: Niland Katherine , Cohen Rhoda , Briefel Ronette , Hu Mindy , Magness Allison , Crepinsek Mary Kay 
Published: November 2023

Accuracy in the collection of children's food consumption remains an important issue in nutrition research and policy. For an evaluation of the Canned, Frozen, and Dried pilot project for the Fresh Fruit and Vegetable Program, we collected student dietary recalls and menu surveys of school meal and FFVP offerings in 34 pilot schools in 4 pilot states in school year 2014–2015. We collected in‐school dietary recalls for elementary school students in grades 4–6 (1,255 in the fall semester and 1,236 in the spring semester). We implemented a dietary recall method that engaged students, minimized time away from class, and improved accuracy in coding foods and their amounts. During data collection for a target week in each school, trained interviewers met with selected students in the morning to describe how to list the items consumed in school on the Foods Eaten in School Today (FEST) food diary. During the school day, trained interviewers also completed a menu survey about the school meal and FFVP offerings with the school's foodservice manager. At the end of the school day, the same interviewer met individually with each student to administer the recall interview, using the foods listed on the diary and school menu survey as a guide. The interviewer recorded the foods and their amounts consumed using the Automated Self‐Administered 24—Adult Version, 2014 (ASA‐24) software developed by the National Cancer Institute. We selected the ASA‐24‐Adult version because it contained more detailed food‐level probes than the child version (ASA‐24‐Kids). We also modified the ASA‐24 to capture specific school sources of foods as: school breakfast, FFVP snack, school lunch, home, or other. USDA's Survey Net system (version 4.0) was used to manually code hard copy menu survey items including all FFVP snacks as well as school lunch and breakfast items. To provide standardized food codes and more accurate portion size information for the in‐school dietary intake, school foods reported in the dietary recall were matched to the coded school menu survey file for the dietary recall student‐level food and nutrient level analysis. We believe this represents the first time that student record‐keeping (the FEST form) combined with ASA‐24 administration by interviewers was used in a large scale study of U.S. elementary school students.Support or Funding InformationEvaluation funded by the Food and Nutrition Service, USDA.
Determination of a Lower Limit of Para‐Aminobenzoic Acid (PABA) Recovery for Identifying Complete 24‐h Urine Collections by High‐Performance Liquid Chromatography (HPLC)
Authors: Taylor Brittney R. , Sagi‐Kiss Virag , Freedman Laurence , O'Brien Diane , Johnston Carol , Tasevska Natasha 
Published: November 2023

BackgroundPara‐aminobenzoic acid (PABA) is a marker commonly used to assess the completeness of 24‐h urine collections in dietary biomarker studies.[1] Spectrophotometry and High‐Performance Liquid Chromatography (HPLC) are the two techniques applied to quantify the percent recovery of orally administered PABA in urine. While the spectrophotometric method uses instrumentation widely available in laboratories, the HPLC method has higher specificity for quantifying PABA.[2] The lower limit of the acceptable recovery of PABA in urine for identifying complete 24‐h urine collections by the spectrophotometric method is 85%,[1] while an agreed limit by the HPLC method is lacking.MethodsUnder highly controlled conditions, 12 participants took three tablets of potassium aminobenzoate (POTABA) per day containing 240 mg of PABA in total, and collected 24‐h urine samples every other day over a 15‐day period (8 collections in total). Eighteen of 96 24‐h urine collections were excluded due to being identified as incomplete based on the spectrophotometric method (n=3) or self‐report (n=10), invalid HPLC data (n=1), use of medications with similar structure to PABA by participants (n=3), or missed POTABA tablet (n=1). Seventy‐eight 24‐h urine collections were available for analysis, and were measured for PABA using both spectrophotometry and HPLC. The 5th percentile of the distribution of the PABA percent recoveries was used as the lower limit for accepting complete 24‐h urine collections by the HPLC method.ResultsThe mean ± SD of 24‐h PABA recoveries measured by spectrophotometry was 108.3 ± 11.9% and 259.9 ± 28.6 mg/24‐h urine, ranging from 86 to 134% and 207 to 322 mg/24‐h urine, respectively. The PABA recoveries as measured by the HPLC method were 87.4 ± 8.6 % and 209.7 ± 20.8 mg/24‐h urine, ranging from 72 to 114% and 173 to 274 mg/24‐h urine, respectively. The 5th percentile of the distribution of the PABA percent recovery in urine by the HPLC was 76% and 181.7 mg/24‐h urine of the orally administered dose.ConclusionAs expected, the mean PABA percent recovery in urine by the spectrophotometric method was higher than by the HPLC. Based on the distribution of PABA recoveries determined by the HPLC method in our study population, the lower limit for accepting a 24‐h urine collection as complete was found to be 76% of the orally administered PABA dose, similar to what has been suggested by other authors.[2]Support or Funding InformationNCI R01 CA197902
Household dietary diversity indicators in rural Central America
Authors: Sibrian Ricardo , de Fulladolsa Patricia Palma 
Published: November 2023

ObjectiveFANTA (2006) and FAO (2012) proposed household dietary diversity scores (HDDS) derived from minimal food consumption data. D'Errico et al (2016) proposed the Shannon‐Wiener and Simpson indices applied to HDDS for food security resilience. WFP (2008) proposed a Food Consumption Score (FCS) weighting HDDS by number of days in a week food was consumed and nutritional importance. This paper proposes new HDDS weighted by utilization coefficients (HDDSU), by nutrient content (HDDSN) and by both (HDDSUN).MethodsThe data on food consumption from 702 households were collected for a seven‐day period in bordering rural communities of El Salvador, Guatemala, Honduras and Nicaragua in 2013, 2014 and 2015. HDDS and new scores HDDSU, HDDSN and HDDSUN for FAO, FANTA and WFP considered 16, 12 and nine food groups respectively and nine for WFP‐FCS with relative nutritional weights only. HDDS and new scores distributions for FAO, FANTA and WFP, and WFP FCS with relative nutritional weights only were estimated as well as correlations between food energy and all scores.ResultsHDDS, HDDSU, HDDSE and HDDSUE distributions based on FAO and FANTA food groupings were similar for small number of food groups consumed, while those based on WFP food groupings behaved differently. Main food groups identified by HDDS were ten in 16 for FAO, ten in 12 for FANTA HDDS, and all nine for WFP; while by FCS, HDDSU, HDDSE and HDDSUE scores identified fewer important food groups for FAO, FANTA and WFP dietary diversity. The correlations between energy intake and dietary diversity scores for FAO, FANTA and WFP were close, ranging from 0.28 to 0.35.ConclusionsIn rural populations of bordering communities in Central America, New scores HDDSU, HDDSE, and HDDSUE provided better results for assessing household dietary diversity than HDDS scores. The new scores weighting by utilization coefficients (HDDSU), nutrient content (HDDSE for example food energy), and both (HDDSUE) identified better the importance of food groups for food and nutrition security. Correlations between dietary energy intake and all household dietary diversity scores analysed were very similar. Policy implications refer to the promotion of main food groups and enhancing potential food groups identified by new scores for improving household dietary diversity in vulnerable populations.
Gender analysis of dishes with high contribution of energy and nutrient intakes among Korean adults
Authors: Kang Minji , Lee Jung Eun , Shim Jae Eun , Paik Hee‐Young 
Published: November 2023

Although differences in food preferences and food choices between men and women were observed, gender differences have been considered scarcely during the development of food frequency questionnaire (FFQ). We previously reported that only 2.5% of the FFQs have been developed in a gender‐specific way in dish item selection.1) We aim to proceed to develop gender‐specific FFQs to compare the selection of dish items between men and women. We investigated the gender differences in a list of dish items with high contribution of energy and 15 nutrients. The study used one day 24h recall data of 7,952 participants (n=3,250 for men; n=4,702 for women) aged 19–64 years who participated in the 2013–2014 Korean National Health and Nutrition Examination Survey (KNHANES). Dish items were selected by analyzing contribution to absolute intake and variability in energy and 15 nutrient intakes. Dish items covering more than 80% of between‐person variation in each nutrient intake were chosen separately among three groups; men and women combined, men, and women. The numbers of dish items selected were 133 in men and women combined, 126 in men, and 153 in women. Compared to 133‐dish items selected in men and women combined, 15‐dish items (11.9%) from the list of men and 30‐dish items (19.6%) from the list of women were not included. These results indicate that developing FFQ without considering gender may produce erroneous results of dietary assessment, possibly with larger errors in women. Further studies are warranted.Support or Funding InformationThis research was supported by Support Program for Women in Science, Engineering and Technology through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (Grant no. 2016H1C3A1903202).