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UC Davis Previously Published Works

Dietary resistant starch supplementation increases gut luminal deoxycholic acid abundance in mice

(2024)

Bile acids (BA) are among the most abundant metabolites produced by the gut microbiome. Primary BAs produced in the liver are converted by gut bacterial 7-α-dehydroxylation into secondary BAs, which can differentially regulate host health via signaling based on their varying affinity for BA receptors. Despite the importance of secondary BAs in host health, the regulation of 7-α-dehydroxylation and the role of diet in modulating this process is incompletely defined. Understanding this process could lead to dietary guidelines that beneficially shift BA metabolism. Dietary fiber regulates gut microbial composition and metabolite production. We tested the hypothesis that feeding mice a diet rich in a fermentable dietary fiber, resistant starch (RS), would alter gut bacterial BA metabolism. Male and female wild-type mice were fed a diet supplemented with RS or an isocaloric control diet (IC). Metabolic parameters were similar between groups. RS supplementation increased gut luminal deoxycholic acid (DCA) abundance. However, gut luminal cholic acid (CA) abundance, the substrate for 7-α-dehydroxylation in DCA production, was unaltered by RS. Further, RS supplementation did not change the mRNA expression of hepatic BA producing enzymes or ileal BA transporters. Metagenomic assessment of gut bacterial composition revealed no change in the relative abundance of bacteria known to perform 7-α-dehydroxylation. P. ginsenosidimutans and P. multiformis were positively correlated with gut luminal DCA abundance and increased in response to RS supplementation. These data demonstrate that RS supplementation enriches gut luminal DCA abundance without increasing the relative abundance of bacteria known to perform 7-α-dehydroxylation.

Prenatal exposure to social adversity and infant cortisol in the first year of life

(2024)

Exposure to social adversity has been associated with cortisol dysregulation during pregnancy and in later childhood; less is known about how prenatal exposure to social stressors affects postnatal cortisol of infants. In a secondary analysis of data from a longitudinal study, we tested whether a pregnant woman's reports of social adversity during the third trimester were associated with their infant's resting cortisol at 1, 6, and 12 months postnatal. Our hypothesis was that prenatal exposure to social adversity would be associated with elevation of infants' cortisol. Measures included prenatal survey reports of social stressors and economic hardship, and resting cortisol levels determined from infant saliva samples acquired at each postnatal timepoint. Data were analyzed using linear mixed effects models. The final sample included 189 women and their infants (46.56% assigned female sex at birth). Prenatal economic hardship was significantly associated with infant cortisol at 6 months postnatal; reports of social stressors were not significantly associated with cortisol at any time point. Factors associated with hardship, such as psychological distress or nutritional deficiencies, may alter fetal HPA axis development, resulting in elevated infant cortisol levels. Developmental changes unique to 6 months of age may explain effects at this timepoint. More work is needed to better comprehend the complex pre- and post-natal physiologic and behavioral factors that affect infant HPA axis development and function, and the modifying role of environmental exposures.

Cover page of Investigation of the seroprevalence to equine coronavirus and SARS-CoV-2 in healthy adult horses recently imported to the United States.

Investigation of the seroprevalence to equine coronavirus and SARS-CoV-2 in healthy adult horses recently imported to the United States.

(2024)

Adult horses are susceptible to equine coronavirus (ECoV) and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), although, only ECoV has been linked to clinical disease. Little information is available regarding the seroprevalence against ECoV and SARS-CoV-2 in adult healthy horses. The goal of the present study was to determine the seroprevalence against two coronaviruses known to infect horses using convenience samples collected from horses recently imported from Europe to the United States from 2019 to 2023. A total of 385 banked serum samples were tested against ECoV and SARS-CoV-2 using previously validated ELISA assays. Prevalence factors including date of arrival in the United States, signalment and country of origin were available for the majority of the horses. A total of 9/385 (2.3%) and 4/385 (1.0%) horses tested seropositive for ECoV and SARS-CoV-2, respectively. The ECoV seropositive horses were all mares, ages 4 to 26 years (median 9 years) and originated from Germany, the Netherlands, Ireland, Belgium and Italy. These mares were predominantly imported during the summer and fall months. All SARS-CoV-2 seropositive horses were mares ages 5 to 10 years (median 7.5 years) imported from the Netherlands and the United Kingdom. The majority of the SARS-CoV-2 seropositive horses were imported during the colder months of the year. The study results support the presence of ECoV in Europe and report on the first SARS-CoV-2 seropositive healthy adult horses outside the United States. Commingling for movements by air and close contact to humans may predispose transmission with ECoV and SARS-CoV-2, respectively.

Cover page of Digital health outreach to promote postpartum screening after gestational diabetes: A randomized factorial pilot study.

Digital health outreach to promote postpartum screening after gestational diabetes: A randomized factorial pilot study.

(2024)

OBJECTIVE: We examined the acceptability and feasibility of a multi-component digital health outreach intervention to promote uptake of guideline-recommended postpartum screening for type 2 diabetes among patients with gestational diabetes (GDM). METHODS: We conducted a 24 randomized factorial experiment as part of the Multiphase Optimization Strategy (MOST) preparation phase for developing behavioral interventions. Participants with current or recent GDM in an integrated healthcare system were randomized to receive an outreach message with up to four intervention components, designed to be self-administered in about 10 min and efficiently delivered online via REDCap: a streamlined values affirmation, personalized information on diabetes risk, an interactive motivational interviewing-based component, and an interactive action planning component. Patient-reported acceptability and feasibility outcomes were assessed via survey. RESULTS: Among 162 participants, 72% self-identified with a racial/ethnic minority group. Across components, acceptability scores averaged 3.9/5; ≥91% of participants read most or all of the outreach message; ≥89% perceived the amount of information as about right; and ≥ 87% completed ≥1 interactive prompt. CONCLUSION: Each intervention component was acceptable to diverse patients and feasible to deliver in a brief, self-directed, online format. INNOVATION: These novel components target unaddressed barriers to patient engagement in guideline-recommended postpartum diabetes screening and adapt theory-based behavior change techniques for large-scale use.

Cover page of Analysis of mousy off-flavor compound 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization in sour beer.

Analysis of mousy off-flavor compound 2-Acetyl-tetrahydropyridine using Liquid Chromatography Mass Spectrometry with Electrospray Ionization in sour beer.

(2024)

Mousy off-flavor describes N-heterocycles compounds related to spoilage in the brewing industry. It has also been identified in sour beers through sensory analysis. Therefore, preventing spoilage N-heterocycles development is essential to preserve end-products and obviate economic losses. To this day, no methods or protocols have been reported to identifying mousy off-flavor compounds in a beer matrix. The main objective of this work was to develop a standardized quantification method for 2-acetyl-3,4,5,6-tetrahydropyridine (ATHP) in beer matrix, by Liquid Chromatography Mass Spectrometry with Electrospray Ionization (LC-MS-ESI). Extraction of ATHP in the samples was performed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique. Over a dozen different potentially mousy cask-aged sour beers including other spontaneously fermented beverages were provided, based on sensory analysis, to determine the variation in ATHP levels. Results indicated ATHP was found in all the samples, ranging from 1.64 ± 0.06 to 57.96 ± 2.15 µg L-1. Herein, we described our detection method of mousy-off flavor compounds which enables future research to mitigate the occurrence of such defects in fermented beverages matrix.•ATHP content in samples varied from 1.64 ± 0.06 to 57.96 ± 2.15 µg L-1.•The recovery range of ATHP using LC-MS-ESI varied from 71% to 97%.•Basified QuEChERS salting-out procedure is applicable for ATHP extraction from beer and other fermented beverages matrices.

Cover page of Helping Faculty Teach Software Performance Engineering

Helping Faculty Teach Software Performance Engineering

(2024)

Over the academic year 2022–23, we discussed the teaching of software performance engineering with more than a dozen faculty across North America and beyond. Our outreach was centered on research-focused faculty with an existing interest in this course material. These discussions revealed an enthusiasm for making software performance engineering a more prominent part of a curriculum for computer scientists and engineers. Here, we discuss how MIT’s longstanding efforts in this area may serve as a launching point for community development of a software performance engineering curriculum, challenges in and solutions for providing the necessary infrastructure to universities, and future directions.

Quantitative T2 mapping-based longitudinal assessment of brain injury and therapeutic rescue in the rat following acute organophosphate intoxication

(2024)

Acute intoxication with organophosphate (OP) cholinesterase inhibitors poses a significant public health risk. While currently approved medical countermeasures can improve survival rates, they often fail to prevent chronic neurological damage. Therefore, there is need to develop effective therapies and quantitative metrics for assessing OP-induced brain injury and its rescue by these therapies. In this study we used a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP), to test the hypothesis that T2 measures obtained from brain magnetic resonance imaging (MRI) scans provide quantitative metrics of brain injury and therapeutic efficacy. Adult male Sprague Dawley rats were imaged on a 7T MRI scanner at 3, 7 and 28 days post-exposure to DFP or vehicle (VEH) with or without treatment with the standard of care antiseizure drug, midazolam (MDZ); a novel antiseizure medication, allopregnanolone (ALLO); or combination therapy with MDZ and ALLO (DUO). Our results show that mean T2 values in DFP-exposed animals were: (1) higher than VEH in all volumes of interest (VOIs) at day 3; (2) decreased with time; and (3) decreased in the thalamus at day 28. Treatment with ALLO or DUO, but not MDZ alone, significantly decreased mean T2 values relative to untreated DFP animals in the piriform cortex at day 3. On day 28, the DUO group showed the most favorable T2 characteristics. This study supports the utility of T2 mapping for longitudinally monitoring brain injury and highlights the therapeutic potential of ALLO as an adjunct therapy to mitigate chronic morbidity associated with acute OP intoxication.

Cover page of METformin for the MINimization of Geographic Atrophy Progression (METforMIN): A Randomized Trial

METformin for the MINimization of Geographic Atrophy Progression (METforMIN): A Randomized Trial

(2024)

Purpose

Metformin use has been associated with a decreased risk of age-related macular degeneration (AMD) progression in observational studies. We aimed to evaluate the efficacy of oral metformin for slowing geographic atrophy (GA) progression.

Design

Parallel-group, multicenter, randomized phase II clinical trial.

Participants

Participants aged ≥ 55 years without diabetes who had GA from atrophic AMD in ≥ 1 eye.

Methods

We enrolled participants across 12 clinical centers and randomized participants in a 1:1 ratio to receive oral metformin (2000 mg daily) or observation for 18 months. Fundus autofluorescence imaging was obtained at baseline and every 6 months.

Main outcome measures

The primary efficacy endpoint was the annualized enlargement rate of the square root-transformed GA area. Secondary endpoints included best-corrected visual acuity (BCVA) and low luminance visual acuity (LLVA) at each visit.

Results

Of 66 enrolled participants, 34 (57 eyes) were randomized to the observation group and 32 (53 eyes) were randomized to the treatment group. The median follow-up duration was 13.9 and 12.6 months in the observation and metformin groups, respectively. The mean ± standard error annualized enlargement rate of square root transformed GA area was 0.35 ± 0.04 mm/year in the observation group and 0.42 ± 0.04 mm/year in the treatment group (risk difference = 0.07 mm/year, 95% confidence interval = -0.05 to 0.18 mm/year; P = 0.26). The mean ± standard error decline in BCVA was 4.8 ± 1.7 letters/year in the observation group and 3.4 ± 1.1 letters/year in the treatment group (P = 0.56). The mean ± standard error decline in LLVA was 7.3 ± 2.5 letters/year in the observation group and 0.8 ± 2.2 letters/year in the treatment group (P = 0.06). Fourteen participants in the metformin group experienced nonserious adverse events related to metformin, with gastrointestinal side effects as the most common. No serious adverse events were attributed to metformin.

Conclusions

The results of this trial as conducted do not support oral metformin having effects on reducing the progression of GA. Additional placebo-controlled trials are needed to explore the role of metformin for AMD, especially for earlier stages of the disease.

Financial disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Cover page of Understanding the mechanical behavior of intrauterine devices during simulated removal

Understanding the mechanical behavior of intrauterine devices during simulated removal

(2024)

Objective

To evaluate differences based on intrauterine device (IUD) frame geometry in force, and stress, and strain at the stem/arms junction during simulated IUD removal.

Study design

We manufactured injection-molded frame models for three Nova-T IUDs (Mirena [model M]; Liletta [model L]; Kyleena [model K]) and a Tatum-T IUD (Paragard [model P]) at two-times scaling. We created a custom fixture to simulate the uterus and used a screw-driven machine to pull models at various displacement rates through the 10 cm fixture cavity to measure force and strain and calculate stress at the IUD stem/arms junction. We tested models at 30 mm/min and higher displacement rates for exploratory analyses. We used Mann-Whitney U test for statistical testing.

Results

We completed testing at 30 mm/min using five of each Nova-T model and nine model P samples. Resistance against the cavity walls created significantly more force on model P (11.83, interquartile range [IQR] 11.61-12.31) than any Nova-T model samples (p < 0.001). The smaller model K created slightly more median stress (MPa) than the larger model M (0.36 [IQR 0.33-0.38] and 0.79 [IQR 0.76-0.80], respectively, p = 0.008); model P samples generated significantly more median stress than other models (1.70 [IQR 1.67-1.77], p < 0.001). Strain plots demonstrated permanent deformation for some samples during IUD removal simulation. We tested 20 samples at various higher displacement rates up to 2500 mm/min, with stress notably increasing for model P samples with increasing rates. No fractures occurred.

Conclusions

Force and stress at the stem/arms junction are higher with Tatum-T-shaped compared to Nova-T-shaped IUD models under the same testing conditions, and a higher speed of extraction causes more stress.

Implications

Sharp corners create vulnerability under static and fatigue loading in structural components due to increased local stresses. Our findings suggest that IUDs with Tatum-T frames should be removed slowly to minimize the stress at the stem/arms junction. Future studies can provide more information if performed with commercially available products.