Racial/Ethnic Disparities in Club Drug Use, Situational Club Drug Use during Sex, and Sexual Risk Behaviors among Alcohol-Using Men Who Have Sex with Men (MSM) in San Francisco

BACKGROUND

Club drug use-including 3,4-Methylenedioxymethamphetamine, ketamine, crack/cocaine, hallucinogens, gamma hydroxybutyrate, volatile nitrites, and methamphetamine-has been linked to sexual risk behaviors among MSM. Few studies examine how the use of club drugs and the association between club drug use during sex and sexual risk may differ by race/ethnicity.

METHODS

Using data from a cross-sectional study among alcohol-using MSM in San Francisco (n = 252), we examined the associations between the interaction of race/ethnicity and club drug use during sex, and the following behavioral outcomes: any condomless anal intercourse (CAI), insertive CAI, receptive CAI, and any serodiscordant sex in the past six months. All models controlled for income, HIV status, relationship status, age, and current use of a biomedical HIV prevention tool (i.e., Pre-Exposure Prophylaxis [PrEP] or antiretroviral therapy).

RESULTS

There were significant racial differences in club drug use (p < 0.001) and club drug use during sex (p = 0.01). Asian/Pacific Islander (API) and Latino participants reported using club drugs the most at 78.8% and 79%, respectively. Among users of club drugs, club drug use during sex was most common among Black (100%), and Latino MSM (93%). Significant interactions between race/ethnicity and club drug use during sex were observed for CAI (p = 0.02), insertive CAI (p = 0.01), and receptive CAI (p = 0.01). API participants who used club drug during sex had higher odds of reporting CAI (aOR = 15.27, CI = 1.50-155.34), insertive CAI (aOR = 21.11, CI = 2.04-218.10), and receptive CAI (aOR = 21.11, CI = 2.04-218.10).

CONCLUSIONS

Given the differing rates of club drug use during sex by race/ethnicity and the role race/ethnicity plays in modifying the relationships between club drug use during sex and sexual risk behaviors, culturally-tailored interventions may be needed to address the needs of ethnically-diverse, club drug-using MSM.

Role of Polyphenols from the Aqueous Extract of Aloysia citrodora in the Inhibition of Aflatoxin B1 Synthesis in Aspergillus flavus

Aflatoxin B1 (AFB1) is a mycotoxin considered a potent carcinogen for humans that contaminates a wide range of crops. Various strategies have been established to reduce or block the synthesis of AFB1 in food and feed. The use of aqueous extracts derived from plants with high antioxidant activity has been a subject of study in recent years due to their efficacy in inhibiting AFB1. In this study, we assessed the effect of Aloysia citrodora aqueous extract on Aspergillus flavus growth and on AFB1 production. A bio-guided fractionation followed by High Performance Liquid Chromatography (HPLC) and Mass spectrometry analysis of the active fraction were applied to identify the candidate molecules responsible for the dose-effect inhibition of AFB1 synthesis. Our results revealed that polyphenols are the molecules implicated in AFB1 inhibition, achieving almost a total inhibition of the toxin production (99%). We identified luteolin-7-diglucuronide as one of the main constituents in A. citrodora extract, and demonstrated that it is able to inhibit, by itself, AFB1 production by 57%. This is the first study demonstrating the anti-Aflatoxin B1 effect of this molecule, while other polyphenols surely intervene in A. citrodora anti-AFB1 activity.

Evidence of Chaos in Electroencephalogram Signatures of Human Performance: A Systematic Review

(1) Background: Chaos, a feature of nonlinear dynamical systems, is well suited for exploring biological time series, such as heart rates, respiratory records, and particularly electroencephalograms. The primary purpose of this article is to review recent studies using chaos theory and nonlinear dynamical methods to analyze human performance in different brain processes. (2) Methods: Several studies have examined chaos theory and related analytical tools for describing brain dynamics. The present study provides an in-depth analysis of the computational methods that have been proposed to uncover brain dynamics. (3) Results: The evidence from 55 articles suggests that cognitive function is more frequently assessed than other brain functions in studies using chaos theory. The most frequently used techniques for analyzing chaos include the correlation dimension and fractal analysis. Approximate, Kolmogorov and sample entropy account for the largest proportion of entropy algorithms in the reviewed studies. (4) Conclusions: This review provides insights into the notion of the brain as a chaotic system and the successful use of nonlinear methods in neuroscience studies. Additional studies of brain dynamics would aid in improving our understanding of human cognitive performance.

Prevalence and Correlates of Violence Experienced by Trans Women

Objectives: To measure the prevalence and correlates of intimate partner, physical, and sexual violence experienced by trans women. Materials and Methods: A National HIV Behavioral Surveillance (NHBS) Study of 201 trans women was conducted in San Francisco from July 2019 to February 2020 using respondent-driven sampling. Prevalence ratio tests were used to test differences in the prevalence of violence by demographic characteristics including housing status. Results: Among 201 trans women interviewed, 26.9% were currently homeless. In the past year, 59.7% had been homeless, 34.3% changed housing, 60.7% had a housing situation other than renting or owning. Experiences of violence were common: 36.8% experienced any form of violence, including sexual (16.9%), intimate partner (14.9%), and other physical (25.4%) in the past year. Experiences of violence were significantly associated with multiple measures of housing insecurity. Younger age, being misgendered, and substance use were also associated with experiences of violence. Conclusions: Trans women face dual crises in housing and violence. Affordable, subsidized, and safe housing has the potential to reduce the exposure and vulnerability to violence faced by trans women.

Enhanced Automatic Segmentation for Superficial White Matter Fiber Bundles for Probabilistic Tractography Datasets

This paper presents an enhanced algorithm for automatic segmentation of superficial white matter (SWM) bundles from probabilistic dMRI tractography datasets, based on a multi-subject bundle atlas. Previous segmentation methods use the maximum Euclidean distance between corresponding points of the subject fibers and the atlas centroids. However, this scheme might include noisy fibers. Here, we propose a three step approach to discard noisy fibers improving the identification of fibers. The first step applies a fiber clustering and the segmentation is performed between the centroids of the clusters and the atlas centroids. This step removes outliers and enables a better identification of fibers with similar shapes. The second step applies a fiber filter based on two different fiber similarities. One is the Symmetrized Segment-Path Distance (SSPD) over 2D ISOMAP and the other is an adapted version of SSPD for 3D space. The last step eliminates noisy fibers by removing those that connect regions that are far from the main atlas bundle connections. We perform an experimental evaluation using ten subjects of the Human Connectome (HCP) database. The evaluation only considers the bundles connecting precentral and postcentral gyri, with a total of seven bundles per hemisphere. For comparison, the bundles of the ten subjects were manually segmented. Bundles segmented with our method were evaluated in terms of similarity to manually segmented bundles and the final number of fibers. The results show that our approach obtains bundles with a higher similarity score than the state-of-the-art method and maintains a similar number of fibers.Clinical relevance-Many brain pathologies or disorders can occur in specific regions of the SWM automatic segmentation of reliable SWM bundles would help applications to clinical research.

Modifying the Gut Microbiome Through Diet or Antibiotics Alters Bone Phenotypes in Older Mice

Objectives

Gut microbiota have been shown to influence bone quality and quantity, both risk determinants for osteoporosis. Previous research in young mice showed oral antibiotic treatment during rapid bone gain impaired bone tissue quality. We sought to determine if modifying the gut microbiome of aged mice through diet or antibiotic treatment affects bone geometry and/or strength.

Methods

A high (HG) or low glycemic (LG) diet was fed in equal amounts to 12-mo. male mice. The diets differed only by starch composition, which was 100% rapidly digested amylopectin in the HG diet or 30% amylopectin/70% amylose in the LG diet. A third group received the LG diet containing antibiotics (ampicillin and neomycin; LGAbx). Feces were collected at baseline and after 10 months of treatment and 16s rRNA sequencing was performed followed by ecological diversity and differential abundance analysis. Femora were harvested after 12 months of treatment for analysis of bone geometry and strength via mechanical testing and imaging.

Results

Antibiotic treatment reduced alpha diversity, including an average 92% reduction in observed OTUs from baseline compared with 30% reduction in the other groups. Both diet and antibiotic treatment significantly altered taxonomic composition, including an expansion of Proteobacteria in response to antibiotics.

Whole bone strength is determined by a combination of the section modulus (the measure of geometry most closely related to bending strength) and the mechanical properties of the bone tissue itself. In HG-fed mice the section modulus was greater than that of the other groups and the bone showed a correspondingly greater strength. However, in LGAbx-fed mice the whole bone strength was 22% lower than bones with similar section modulus in the LG and HG-fed groups, indicating impaired bone tissue material properties.

Conclusions

Altering diet resulted in significant changes to bone geometry and strength, while changes in the gut microbiota associated with antibiotic treatment resulted in a reduction to bone strength which could not be explained by bone geometry. Our study indicates that dietary or antibiotics treatments applied to mice later in life can alter bone properties, which suggests that interventions to improve bone strength may be effective in older adults.

Funding Sources

NIH/NIAMS, BrightFocus Foundation, Stanley N. Gershoff Scholarship.

Mimosa tenuiflora Aqueous Extract: Role of Condensed Tannins in Anti-Aflatoxin B1 Activity in Aspergillus flavus

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.

Abstract P684: Treatment of Hypercoagulability-Induced New Neurovascular Events Using Enoxaparin vs DOACs (THINNED): A Retrospective Study

Introduction: The incidence of stroke is higher in patients with malignancy, especially within a few months of diagnosis and in more aggressive cancers. This phenomenon may be explained by an inherent hypercoagulable state, tumor embolism, vessel infiltration, or as a side effect from cancer treatment. Notably, stroke in cancer patients is associated with poor functional outcomes and reduced survival. Currently, however, there are no clear guidelines for antithrombotic management for prevention of recurrent strokes in these patients.

Methods: We conducted a single-center retrospective chart review from 2013-2019. All adult patients with an ischemic stroke occurring with active malignancy and who then received either a direct oral anticoagulant (DOAC) or low molecular weight heparin (LMWH) were included. Patients with hemorrhagic stroke, an intracranial malignancy, or who were immediately admitted to hospice were excluded.

Results: A total of 55 patients were included with a mean age of 71.8 years (range 28-96), 60% females, 87.3% first-time strokes, and 54.9% with metastatic disease. After stroke, 25 patients received a DOAC and 30 received LMWH for anticoagulation with a mean follow-up of 403 days. Between these two groups, most presentation and treatment characteristics were similar except for baseline hypertension, hyperlipidemia, additional initiation of an antiplatelet, and follow-up time. There was no difference in either stroke recurrence (DOAC vs LMWH: OR 2.61 [0.51-13.45], p=0.252) or time to recurrent stroke (DOAC vs LMWH: HR 1.68, p=0.446), but both analyses required adjustment for additional initiation of an antiplatelet—which was significantly protective regardless of anticoagulation choice (p=0.021* and p=0.017*, respectively). There was a trend towards improved survival if placed on a DOAC (HR 0.27, p=0.051), even after adjusting for metastatic disease.

Conclusions: In this initial study of cancer patients with ischemic stroke, anticoagulation choice made no difference on stroke recurrence; however, addition of an antiplatelet agent was significantly protective. There was also a trend towards improved survival on a DOAC. Additional prospective data incorporating a larger sample size could further validate these findings.

Distribution of Burkholderia cepacia complex species isolated from industrial processes and contaminated products in Argentina

Burkholderia cepacia complex (Bcc) members have clinical relevance as opportunistic pathogens in patients with cystic fibrosis and are responsible of numerous nosocomial infections. These closely related bacteria are also reported as frequent contaminants of industrial products. In this retrospective study, we use PCR and recA gene sequence analysis to identify at species level Bcc isolates recovered from massive consumption products and industrial processes in Argentina during the last 25 years. The sequences obtained were also compared with recA sequences from clinical Bcc isolates deposited in GenBank database. We detected Bcc in purified water and preserved products from pharmaceutics, cosmetics, household cleaning articles, and beverages industries. B. contaminans (which is prevalent among people with cystic fibrosis in Argentina) was the most frequent Bcc species identified (42% of the Bcc isolates studied). B. cepacia (10%), B. cenocepacia (5%), B. vietnamiensis (16%), B. arboris (3%), and the recently defined B. aenigmatica (24%) were also detected. Rec A sequences from all B. cepacia and most B. contaminans industrial isolates obtained in this study displayed 100% identity with recA sequences from isolates infecting Argentinean patients. This information brings evidence for considering industrial massive consumption products as a potential source of Bcc infections. In addition, identification at species level in industrial microbiological laboratories is necessary for a better epidemiological surveillance. Particularly in Argentina, more studies are required in order to reveal the role of these products in the acquisition of B. contaminans infections.

The dance of the nanobubbles: detecting acoustic backscatter from sub-micron bubbles using ultra-high frequency acoustic microscopy

Nanobubbles have gained attention for their use as highly stable ultrasound (US) contrast agents, but assessment of individual nanobubble size remains a challenge. Current sizing techniques require either extensive sample preparation or depend on assumed values of nanobubble density that are not well characterized. An US based approach would be desirable; however, probing individual nanobubbles using US transducers at clinical frequencies is not feasible due to the comparatively long acoustic wavelengths employed. Here we present a technique which can be used to estimate nano- or microbubble size by virtue of the amount of motion detected in an M-Mode image acquired using an acoustic microscope equipped with a 200 MHz transducer. A sample of a bubble-containing solution is incorporated into a phantom composed of molten agarose. The solidified agarose gel contains pores with well-defined sizes dictated by the agarose concentration. Bubbles in the gel matrix that are smaller in diameter than the gel pore size are capable of undergoing stochastic motion which manifests as intensity fluctuations in M-Mode images. Conversely, bubbles which are larger than the agarose pores become trapped and produce static M-Mode intensity patterns. In this study, agarose gels with concentrations ranging from 0.25% to 1.25% (mean pore sizes ranging from 2.68 μm to 0.34 μm) were loaded with either nanobubbles (mean diameter 0.326 μm) or microbubbles (mean diameter 2.71 μm) and imaged at 200 MHz. In the nanobubble loaded gels, M-Mode fluctuations were clearly visible up to a gel concentration of 1% (pore size of 0.39 μm). In contrast, the microbubble loaded gels exhibited minimal M-Mode fluctuation even at agarose concentrations of 0.25% (2.68 μm pore size). Autocorrelation curves generated from the M-Mode data demonstrated a clear trend of curve flattening (loss of motion) when the pore size was comparable to mean bubble diameter, indicating that individual bubbles trapped in the agarose pores are the main source of acoustic backscatter. In the future, decay parameters extracted from the autocorrelation curves could potentially be used as indicators of mean bubble diameter for bubble populations of unknown size.

Hepatocellular Carcinoma Demonstrates Heterogeneous Growth Patterns in a Multicenter Cohort of Patients With Cirrhosis

BACKGROUND AND AIMS

There are limited data on hepatocellular carcinoma (HCC) growth patterns, particularly in Western cohorts, despite implications for surveillance, prognosis, and treatment. Our study's aim was to quantify tumor doubling time (TDT) and identify correlates associated with indolent and rapid growth.

APPROACH AND RESULTS

We performed a retrospective multicenter cohort study of patients with cirrhosis diagnosed with HCC from 2008 to 2017 at six US and European health systems with two or more contrast-enhanced imaging studies performed ≥ 30 days apart prior to HCC treatment. Radiologists independently measured tumors in three dimensions to calculate TDT and specific growth rate (SGR). We used multivariable ordinal logistic regression to identify factors associated with indolent (TDT > 365 days) and rapid (TDT < 90 days) tumor growth. In the primary cohort (n = 242 patients from four centers), median TDT was 229 days (interquartile range [IQR], 89-627) and median SGR was 0.3% per day (IQR, 0.1%-0.8%). Over one-third (38%) of HCCs had indolent growth, 36.8% intermediate growth, and 25.2% rapid growth. In multivariable analysis, indolent growth was associated with larger tumor diameter (odds ratio [OR], 1.15, 95% confidence interval [CI], 1.03-1.30) and alpha-fetoprotein < 20 ng/mL (OR, 1.90; 95% CI, 1.12-3.21). Indolent growth was more common in nonviral than viral cirrhosis (50.9% versus 32.1%), particularly in patients with T1 HCC (OR, 3.41; 95% CI, 1.08-10.80). Median TDT (169 days; IQR 74-408 days) and SGR (0.4% per day) were similar in an independent cohort (n = 176 patients from two centers).

CONCLUSIONS

In a large Western cohort of patients with HCC, we found heterogeneous tumor growth patterns, with one-fourth exhibiting rapid growth and over one-third having indolent growth. Better understanding different tumor growth patterns may facilitate a precision approach to prognostication and treatment.

The effect of hybrid zinc oxide/graphene oxide (ZnO/GO) nano-catalysts on the photocatalytic degradation of simazine

The photocatalytic degradation of simazine (SIM) was investigated using zinc oxide/graphene oxide (ZnO/GO) composite materials under visible light irradiation. The reaction kinetics was studied to optimize the reaction parameters for efficient degradation of SIM. Batch studies were performed to investigate the effects of initial reaction pH, the loading of the ZnO onto GO, and mass of catalyst on the removal of SIM from aqueous solution. A pH of 2 was determined to be the optimal reaction pH for the different ZnO-loaded GO catalysts. In addition, a mass of 40 mg of catalyst in the reaction was observed to be the most effective for the catalysts synthesized using 20 and 30 mmol of Zn²⁺ ions; whereas a mass of 10 mg was most effective for the ZnO/GO composite material synthesized using 10 mmol Zn²⁺ ions. The reaction was observed to follow a second-order kinetics for the degradation process. Furthermore, the synthesized ZnO/GO composite catalysts resulted in higher reaction rates than those observed for pure ZnO. The 30 mmol ZnO/GO composite expressed a rate of SIM degradation ten times greater than the rate observed for pure ZnO, and sixty-two times greater than the rate of photolysis. In addition, the catalyst cycling exhibited a constant photocatalytic activity for the ZnO/GO composite over three reaction cycles without the need of a conditioning cycle.

Investigation of Vitamin K Quinone Metabolism by Human Gut Bacteria

Objectives

Vitamin K (VK) is a family of structurally-related quinones, phylloquinone (PK) and menaquinones (MKn, n = prenyl units in side chain), that share a common napthoquinone ring (menadione, MD). VK quinones function as an essential dietary nutrient for humans. MD is considered a pro-vitamin form of VK. Plants and bacteria that produce VK quinones (PK and MKn, respectively) use them as an electron carrier in energy production. Little is known about the interaction of dietary VK quinones with gut bacteria, which may be bi-directional. The objective of this study was to investigate the influence of VK quinones and MD on human gut bacteria composition and MKn production.

Methods

Stool from 5 healthy male donors was pooled and inoculated in bioreactors under conditions mimicking the colon (anaerobic, pH 6.8, 37°C) for 48 h. Bioreactors were treated with deuterium (2H)-labeled quinones (2H-PK, 2H-MK4, 2H-MK9 or 2H-MD); no quinones (cell controls); or 2H-quinone treatment with no stool (cell-free controls). Culture aliquots were collected at 0, 5, 10, 24, and 48 h, and separated into pellet and supernatant fractions. Experiments were conducted in triplicate. All fractions were analyzed for VK quinone content using LC-MS. DNA from 0 and 24 h pellet fractions was extracted and amplified for paired-end 16S sequencing on an Illumina MiSeq 2500. Differences in bacterial composition were assessed using PERMANOVA.

Results

Supplemented 2H-quinones accumulated in the pellet fraction over time. This was not observed in cell-free controls and was thus not a function of culture media solubility. Endogenous (unlabeled) production of MKn was unaffected by supplementation of 2H-quinones. Generated 2H-MKn (2H-MK4, 2H-MK9, 2H-MK10, and 2H-MK11) were only detected in 2H-MD supplemented vessels. Community-wide bacterial composition significantly differed between 0 h and 24 h (r2 = 0.85, P = 0.001), but not by quinone treatment.

Conclusions

PK and MKn, dietary viamin K quinones, were not transformed by gut microbes to MKn in vitro, whereas the pro-vitamin quinone MD was transformed to MKn of multiple side chain lengths. Although no quinone induced community-wide changes in bacteria composition, additional analyses are needed to assess species-specific growth promotion.

Funding Sources

USDA ARS and DOD Health Program.

Contrast-enhanced ultrasound with sub-micron sized contrast agents detects insulitis in mouse models of type1 diabetes

In type1 diabetes (T1D) autoreactive T-cells infiltrate the islets of Langerhans, depleting insulin-secreting β-cells (insulitis). Insulitis arises during an asymptomatic phase, prior to clinical diagnosis of T1D. Methods to diagnose insulitis and β-cell mass changes during this asymptomatic phase are limited, precluding early therapeutic intervention. During T1D the islet microvasculature increases permeability, allowing nanoparticles to access the microenvironment. Contrast enhanced ultrasound (CEUS) uses shell-stabilized gas bubbles to provide acoustic backscatter in vasculature. Here, we report that sub-micron sized 'nanobubble' ultrasound contrast agents can be used to measure increased islet microvasculature permeability and indicate asymptomatic T1D. Through CEUS and histological analysis, pre-clinical models of T1D show accumulation of nanobubbles specifically within pancreatic islets, correlating with insulitis. Importantly, accumulation is detected early in disease progression and decreases with successful therapeutic intervention. Thus, sub-micron sized nanobubble ultrasound contrast agents provide a predicative marker for disease progression and therapeutic reversal early in asymptomatic T1D.

Modafinil in Recovery after Stroke (MIRAS): A Retrospective Study

BACKGROUND AND PURPOSE

Acute rehabilitation is known to enhance stroke recovery. However, poststroke lethargy and fatigue can hinder participation in rehabilitation therapies. We hypothesized that in patients with moderate to severe stroke complicated by poststroke fatigue and lethargy early stimulant therapy with modafinil increases favorable discharge disposition defined as transfer to acute inpatient rehabilitation or home.

METHODS

We retrospectively reviewed a cohort of patients with acute stroke admitted to the stroke service over a 3-year period. All patients 18 years or older with confirmed ischemic or hemorrhagic stroke, an NIHSS greater than or equal to 5 and documentation of fatigue/lethargy in clinical documentation were included. We compared patients that were treated with modafinil 50-200 mg to those managed with standard care. The primary outcome measure was discharge disposition. Secondary outcome was 90 day modified Rankin score (mRS). Statistical significance was determined using chi-square test for association and logistic regression models. Logistic regression models were derived in 2 ways with both raw data and an adjusted model that accounted for age, sex, and NIHSS score to account for the lack of randomization.

RESULTS

This study included 199 stroke patients (145 ischemic, 54 hemorrhagic). Seventy-two (36.2%) were treated with modafinil and 129 (64.8%) were discharged to acute inpatient rehabilitation, while none were recommended for discharge home. Median NIHSS for modafinil patients was 13.5 versus 11 for standard care patients (P = .059). In adjusted models, modafinil was associated with higher odds of favorable discharge disposition (OR 2.00, 95% CI 1.01-3.95). Favorable outcome at 90 days defined as mRS less than or equal to 2 occurred more frequently with modafinil (5.6% versus 3.3%) but this did not achieve statistical significance (P > .1). These results occurred despite the modafinil group requiring longer ICU stays and having more in-hospital complications such as infections and need for percutaneous gastrostomy tubes. The benefit of modafinil was seen across all subgroups except those with severe stroke (NIHSS ≥ 15). There were no significant adverse events associated with modafinil administration.

CONCLUSIONS

Modafinil use in acute in-hospital stroke patients with moderate stroke complicated by lethargy and fatigue was associated with improved discharge disposition. Randomized controlled trials are needed to further study the safety, efficacy, and long-term effects of modafinil in this patient population.

Abstract WP381: Modafinil in Recovery After Stroke: A Retrospective Study

Background: Acute rehabilitation is known to enhance stroke recovery. However, post-stroke lethargy and fatigue can hinder participation in rehabilitation therapies. We hypothesized that in patients with moderate to severe stroke, early stimulant therapy with modafinil increases favorable discharge disposition defined as transfer to acute rehabilitation.

Methods: We retrospectively reviewed a cohort of patients with acute stroke admitted over a 3 year period. Patients were excluded for low NIH Stroke Scale score (below 5) or absence of confirmed stroke on brain imaging. We compared patients that were treated with modafinil 50-200mg to those managed with standard care. The primary outcome measure was discharge disposition. Secondary outcome was modified Rankin Score after discharge. Statistical significance was determined using chi-square test for association and logistic regression models.

Results: The study cohort included 199 patients (145 ischemic, 54 hemorrhagic). 72 (36.2%) were treated with modafinil and 129 (64.8%) were discharged to acute rehab. Median NIHSS for modafinil patients vs standard care patients was higher but did not reach statistical significance (median (IQR): 13.5 (15) vs 11 (10), p=0.059). In adjusted models, modafinil was associated with higher odds of favorable discharge disposition (OR 2.00, 95% CI 1.01-3.95). Favorable outcome at 90 days (mRS ≤ 2) occurred more frequently with modafinil (5.6% vs. 3.3%) but this did not achieve statistical significance (p>0.1). The benefit of modafinil was seen across all subgroups of patients, except those with severe stroke (NIHSS > 15). There were no significant complications clearly linked to modafinil administration.

Conclusions: Modafinil use in acute stroke patients with moderate to severe stroke was associated with improved discharge disposition. Randomized controlled trials are needed to further study the safety, efficacy, and long-term effects of modafinil in this population.

Evaluation of the VIDAS Staph Enterotoxin II (SET 2) Immunoassay Method for the Detection of Staphylococcal Enterotoxins in Selected Foods: Collaborative Study

A multilaboratory study was conducted to determine the limit of detection (LOD) of Staphylococcal enterotoxins (SET) in 5 foods. Cooked chicken, ham, potato salad, pasteurized liquid whole milk, and canned mushrooms were each spiked with a different enterotoxin (A, B, C1, D, or E), and tested at 0.25 and 0.5 ng/g SET levels to determine the LOD of the assay for those foods in a collaborative study. Unspiked controls were also included. A total of 19 laboratories representing government and industry participated. In this study, 1674 test portions were analyzed, of which 1638 were used in the statistical analysis. Of the 1638 test portions used in the statistical analysis, 1104 were spiked test portions, of which 1073 were positive by the VIDAS Staph enterotoxin II (SET 2) method. The detection rates at the 0.25 ng/mL level were cooked chicken, 98.2; ham, 99.0; potato salad, 99.1; liquid whole milk, 85.2; and canned mushrooms, 100. The detection rates at the 0.5 ng/mL level were cooked chicken, 97.4; ham, 98.1; potato salad, 100; liquid whole milk, 99.0; and canned mushrooms, 100. The data indicate that the SET 2 method is capable of detecting SET at 0.25 ng/g in cooked chicken, ham, potato salad, and canned mushrooms and at 0.5 ng/g in pasteurized liquid whole milk.

Enumeration of Total Aerobic Microorganisms in Foods by SimPlate® Total Plate Count–Color Indicator Methods and Conventional Culture Methods: Collaborative Study

The relative efficacy of the SimPlate® Total Plate Count–Color Indicator (TPC–CI) method (SimPlate 35°C) was compared with the AOAC Official Method 966.23 (AOAC 35°C) for enumeration of total aerobic microorganisms in foods. The SimPlate TPC–CI method, incubated at 30°C (SimPlate 30°C), was also compared with the International Organization for Standardization (ISO) 4833 method (ISO 30°C). Six food types were analyzed: ground black pepper, flour, nut meats, frozen hamburger patties, frozen fruits, and fresh vegetables. All foods tested were naturally contaminated. Nineteen laboratories throughout North America and Europe participated in the study. Three method comparisons were conducted. In general, there was &lt;0.3 mean log count difference in recovery among the SimPlate methods and their corresponding reference methods. Mean log counts between the 2 reference methods were also very similar. Repeatability (sr) and reproducibility (sR) standard deviations were similar among the 3 method comparisons. The SimPlate method (35°C) and the AOAC method were comparable for enumerating total aerobic microorganisms in foods. Similarly, the SimPlate method (30°C) was comparable to the ISO method when samples were prepared and incubated according to the ISO method.

Visual Immunoprecipitate Assay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.09): Collaborative Study

AOAC Official Method 996.09, Visual Immunoprecipitate Assay (VIP®) for Escherichia coli O157:H7, was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by VIP assay and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment procedure and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 15 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level, where predominantly positive results were expect d, and a low level where fractional recovery was anticipated. Collaborators tested 396 test portions and controls by both methods, for a total of 792 test portions. Of the 396 paired test portions, 75 were positive and 230 were negative by both the VIP and culture methods. Eleven test portions were presumptively positive by VIP and could not be confirmed culturally; 32 were negative by VIP, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the VIP method. There was no statistical difference between results obtained with the VIP for EHEC 8 h method and the culture method except for cooked beef, where the VIP had significantly higher recovery for one inoculation level.

Assurance® Enzyme Immunoassay Eight Hour Method for Detection of Enterohemorrhagic Escherichia coli O157:H7 in Raw and Cooked Beef (Modification of AOAC Official Method 996.10): Collaborative Study

AOAC Official Method 996.10, Assurance® Enzyme Immunoassay (EIA) for Escherichia coli O157:H7 (EHEC), was modified to incorporate a new enrichment protocol using BioControl EHEC8™ medium for testing raw and cooked beef. Foods were tested by EIA and the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) enrichment conditions and the FDA Bacteriological Analytical Manual (BAM) isolation and confirmation techniques. A total of 14 collaborators participated. Raw and cooked ground beef were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. Collaborators tested 378 test portions and controls by both the 8 h EIA and the USDA/FSIS enrichment methods, for a total of 756 test portions. Of the 378 paired test portions, 75 were positive and 212 were negative by both methods. Thirteen test portions were presumptively positive by EIA and could not be confirmed culturally; 30 were negative by EIA, but confirmed positive by culture; and 65 were negative by the culture method, but confirmed positive by the EIA method. There was no statistical difference between results obtained with the Assurance EIA for EHEC 8 h method and the culture method for raw ground beef. The Assurance EIA had a significantly higher recovery for cooked beef.

Contrast enhanced ultrasound imaging by nature-inspired ultrastable echogenic nanobubbles

Advancement of ultrasound molecular imaging applications requires not only a reduction in size of the ultrasound contrast agents (UCAs) but also a significant improvement in the in vivo stability of the shell-stabilized gas bubble. The transition from first generation to second generation UCAs was marked by an advancement in stability as air was replaced by a hydrophobic gas, such as perfluoropropane and sulfur hexafluoride. Further improvement can be realized by focusing on how well the UCAs shell can retain the encapsulated gas under extreme mechanical deformations. Here we report the next generation of UCAs for which we engineered the shell structure to impart much better stability under repeated prolonged oscillation due to ultrasound, and large changes in shear and turbulence as it circulates within the body. By adapting an architecture with two layers of contrasting elastic properties similar to bacterial cell envelopes, our ultrastable nanobubbles (NBs) withstand continuous in vitro exposure to ultrasound with minimal signal decay and have a significant delay on the onset of in vivo signal decay in kidney, liver, and tumor. Development of ultrastable NBs can potentially expand the role of ultrasound in molecular imaging, theranostics, and drug delivery.

Enhancing Tumor Drug Distribution With Ultrasound-Triggered Nanobubbles

Issues with limited intratumoral drug penetration and heterogeneous drug distribution continue to impede the therapeutic efficacy of nanomedicine-based delivery systems. Ultrasound (US)-enhanced drug delivery has emerged as one effective means of overcoming these challenges. Acoustic cavitation in the presence of nanoparticles has shown to increase the cellular uptake and distribution of chemotherapeutic agents in vivo. In this study, we investigated the potential of a drug-loaded echogenic nanoscale bubbles in combination with low frequency (3 MHz), high energy (2 W/cm2) US for antitumor therapy. The doxorubicin-loaded nanobubbles (Dox-NBs) stabilized with an interpenetrating polymer mesh were 171.5 ± 20.9 nm in diameter. When used in combination with therapeutic US, Dox-NBs combined with free drug showed significantly higher (*p < 0.05) intracellular uptake and therapeutic efficacy compared with free drug. When injected intravenously in vivo, Dox-NBs + therapeutic US showed significantly higher (*p < 0.05) accumulation and better distribution of Dox in tumors when compared with free drug. This strategy provides an effective and simple method to increase the local dose and distribution of otherwise systemically toxic chemotherapeutic agents for cancer therapies.

Acute kidney injury after cardiac surgery: prevalence, impact and management challenges

Acute kidney injury (AKI) is a major medical problem that is of particular concern after cardiac surgery. Perioperative AKI is independently associated with an increase in short-term morbidity, costs of treatment, and long-term mortality. In this review, we explore the definition of cardiac surgery-associated acute kidney injury (CSA-AKI) and identify diverse mechanisms and risk factors contributing to the renal insult. Current theories of the pathophysiology of CSA-AKI and description of its clinical course will be addressed in this review. Data on the most promising renal protective strategies in cardiac surgery, from well-designed studies, will be scrutinized. Furthermore, diagnostic tools such as novel biomarkers of AKI and their potential utility will be discussed.

Surgical approach significantly affects the complication rates associated with total hip arthroplasty

AIMS

A variety of surgical approaches are used for total hip arthroplasty (THA), all with reported advantages and disadvantages. A number of common complications can occur following THA regardless of the approach used. The purpose of this study was to compare five commonly used surgical approaches with respect to the incidence of surgery-related complications.

PATIENTS AND METHODS

The electronic medical records of all patients who underwent primary elective THA at a single large-volume arthroplasty centre, between 2011 and 2016, with at least two years of follow-up, were reviewed. After exclusion, 3574 consecutive patients were included in the study. There were 1571 men (44.0%) and 2003 women (56.0%). Their mean age and body mass index (BMI) was 63.0 years (sd 11.8) and 29.1 kg/m² (sd 6.1), respectively. Data gathered included the age of the patient, BMI, the American Society of Anesthesiologists (ASA) score, estimated blood loss (EBL), length of stay (LOS), operating time, the presence of intra- or postoperative complications, type of complication, and the surgical approach. The approaches used during the study were posterior, anterior, direct lateral, anterolateral, and the northern approach. The complications that were recorded included prolonged wound drainage without infection, superficial infection, deep infection, dislocation, aseptic loosening, and periprosthetic fracture. Finally, the need for re-operation was recorded. Means were compared using analysis of variance (ANOVA) and Student's t-tests where appropriate and proportions were compared using the chi-squared test.

RESULTS

A total of 248 patients had 263 complications related to the surgery, with an incidence of 6.94%. The anterior approach had the highest incidence of complications (8.5% (113/1329)) and the posterior approach had the lowest, at 5.85% (97/1657; p = 0.006). Most complications were due to deep infection (22.8%), periprosthetic fracture (22.4%), and prolonged wound drainage (21.3%). The rate of dislocation was 0.84% (14/1657) with the posterior approach and 1.28% (17/1329) with the anterior approach (p = 0.32).

CONCLUSION

Overall, THA has a relatively low complication rate. However, the surgical approach plays a role in the incidence of complications. We found that the posterior approach had a significantly lower overall complication rate compared with the anterior approach, with an equal dislocation rate. Periprosthetic fracture and surgical site infection contributed most to the early complication rates. Cite this article: Bone Joint J 2019;101-B:646-651.

Dietary and Supplemental Menaquinones Accumulate in Liver and Feces of C57BL6 Mice (P06-006-19)

Objectives

Vitamin K (VK) exists in multiple forms. Plant-based phylloquinone (PK) is considered the predominant dietary VK form. However, recent studies have shown bacterially-produced menaquinones (MKn; n = number of prenyl units in side chain) are prevalent in food such as dairy, fermented products, and meat, including pork. It is unknown if dietary MKn are absorbed and metabolized. The objective of this study was to compare MKn concentrations in blood, liver, and feces of mice given purified and food-based MKn to mice fed a VK-deficient (VKD) diet.

Methods

Thirty male and 30 female 8-week old C57BL6 mice were acclimated on a VKD diet for 4 weeks and then maintained on VKD diet, or given a diet containing dietary MK9 (VKD + MK9), or pork (24% of diet, VKD + pork) for 4 weeks. VK forms in diets, blood, liver, and feces were measured using LC-MS. Within each sex, Kruskall-Wallis rank-sum tests were used to compare VK concentrations in VKD + MK9 mice to VKD mice, and to compare VKD + pork mice to VKD mice. VK concentrations are reported as mean ± SD (diets) or geometric mean ± SEM. Significance was set at α = 0.05.

Results

The VKD diet contained 20.6 ± 1.9 ng PK/g diet; the VKD + MK9 diet contained PK (9.2 ± 1.6 ng/g) and MK9 (3820 ± 600 ng/g); and the VKD + pork diet contained PK (11.1 ± 0.6 ng/g), MK4 (38.5 ± 7.8 ng/g), MK9 (34.7 ± 9.8 ng/g), and MK10 (33.2 ± 10 ng/g). Liver MK9 was higher in the VKD + MK9 group than the VKD group (males: 16.8 ± 3.5 vs 3.3 ± 1.1 pmol/g, p = 0.002; females: 192 ± 26 vs 2.4 ± 3.1 pmol/g, p = 0.0001). Liver MK10 was higher in the VKD + pork group than the VKD group (males: 22.9 ± 8.0 vs 5.6 ± 1.3 pmol/g, p = 0.0007; females: 19.5 ± 5.0 vs 6.2 ± 4.0 pmol/g, p = 0.01). In feces, MK9 was higher in the VKD + MK9 group as compared to the VKD group (males: 3460 ± 430 vs 213 ± 56 pmol/g; females: 5360 ± 500 vs 344 ± 84 pmol/g, both p = 0.002). MK6 was greater in the VKD group than the VKD + pork group (males: 828 ± 210 vs 279 ± 49 pmol/g, p = 0.009; females: 679 ± 143 vs 404 ± 57 pmol/g, p = 0.04). No MKn forms were detected in blood.

Conclusions

MKn forms in liver reflect dietary MKn intake. Fecal MKn partially reflect intake, but presence of fecal forms absent in the diet suggests fecal MKn also reflect production by the gut microbiota.

Funding Sources

Supported by the USDA ARS CA 58-1950-7-707 and the Iowa Pork Producers Association.

Rhythmic Food Intake Drives Rhythmic Gene Expression More Potently than the Hepatic Circadian Clock in Mice

Every mammalian tissue exhibits daily rhythms in gene expression to control the activation of tissue-specific processes at the most appropriate time of the day. Much of this rhythmic expression is thought to be driven cell autonomously by molecular circadian clocks present throughout the body. By manipulating the daily rhythm of food intake in the mouse, we here show that more than 70% of the cycling mouse liver transcriptome loses rhythmicity under arrhythmic feeding. Remarkably, core clock genes are not among the 70% of genes losing rhythmic expression, and their expression continues to exhibit normal oscillations in arrhythmically fed mice. Manipulation of rhythmic food intake also alters the timing of key signaling and metabolic pathways without altering the hepatic clock oscillations. Our findings thus demonstrate that systemic signals driven by rhythmic food intake significantly contribute to driving rhythms in liver gene expression and metabolic functions independently of the cell-autonomous hepatic clock.

Sink or float? Characterization of shell-stabilized bulk nanobubbles using a resonant mass measurement technique

Nano-sized shell-stabilized gas bubbles have applications in various fields ranging from environmental science to biomedical engineering. A resonant mass measurement (RMM) technique is demonstrated here as a new and only method capable of simultaneously measuring the size and concentration of buoyant and non-buoyant particles in a nanobubble sample used as a next-generation ultrasound contrast agent.

Reevaluating the Substrate Specificity of the L-Type Amino Acid Transporter (LAT1)

The L-type amino acid transporter 1 (LAT1, SLC7A5) transports essential amino acids across the blood-brain barrier (BBB) and into cancer cells. To utilize LAT1 for drug delivery, potent amino acid promoieties are desired, as prodrugs must compete with millimolar concentrations of endogenous amino acids. To better understand ligand-transporter interactions that could improve potency, we developed structural LAT1 models to guide the design of substituted analogues of phenylalanine and histidine. Furthermore, we evaluated the structure-activity relationship (SAR) for both enantiomers of naturally occurring LAT1 substrates. Analogues were tested in cis-inhibition and trans-stimulation cell assays to determine potency and uptake rate. Surprisingly, LAT1 can transport amino acid-like substrates with wide-ranging polarities including those containing ionizable substituents. Additionally, the rate of LAT1 transport was generally nonstereoselective even though enantiomers likely exhibit different binding modes. Our findings have broad implications to the development of new treatments for brain disorders and cancer.

Characterization of different bubble formulations for blood-brain barrier opening using a focused ultrasound system with acoustic feedback control

Focused ultrasound combined with bubble-based agents serves as a non-invasive way to open the blood-brain barrier (BBB). Passive acoustic detection was well studied recently to monitor the acoustic emissions induced by the bubbles under ultrasound energy, but the ability to perform reliable BBB opening with a real-time feedback control algorithm has not been fully evaluated. This study focuses on characterizing the acoustic emissions of different types of bubbles: Optison, Definity, and a custom-made nanobubble. Their performance on reliable BBB opening under real-time feedback control based on acoustic detection was evaluated both in-vitro and in-vivo. The experiments were conducted using a 0.5 MHz focused ultrasound transducer with in-vivo focal pressure ranges from 0.1-0.7 MPa. Successful feedback control was achieved with all three agents when combining with infusion injection. Localized opening was confirmed with Evans blue dye leakage. Microscopic images were acquired to review the opening effects. Under similar total gas volume, nanobubble showed a more reliable opening effect compared to Optison and Definity (p < 0.05). The conclusions obtained from this study confirm the possibilities of performing stable opening using a feedback control algorithm combined with infusion injection. It also opens another potential research area of BBB opening using sub-micron bubbles.

Role of Surface Tension in Gas Nanobubble Stability Under Ultrasound

Shell-stabilized gas nanobubbles have recently captured the interest of the research community for their potential application as ultrasound contrast agents for molecular imaging and therapy of cancer. However, the very existence of submicron gas bubbles (especially uncoated bubbles) has been a subject of controversy in part due to their predicted Laplace overpressure reaching several atmospheres, making them supposedly thermodynamically unstable. In addition, the backscatter resulting from ultrasound interactions with nanoparticles is not predicted to be readily detectable at clinically relevant frequencies. Despite this, a number of recent reports have successfully investigated the presence and applications of nanobubbles for ultrasound imaging. The mechanism behind these observations remains unclear but is thought to be, in part, influenced heavily by the biophysical properties of the bubble-stabilizing shell. In this study, we investigated the effects of incorporating the triblock copolymer surfactant, Pluronic, into the lipid monolayer of nanobubbles. The impact of shell composition on membrane equilibrium surface tension was investigated using optical tensiometry, using both pendant drop and rising drop principles. However, these techniques proved to be insufficient in explaining the observed behavior and stability of nanobubbles under ultrasound. Additionally, we sought to investigate changes in membrane surface tension (surface pressure) at different degrees of compression (analogous to the bubble oscillations in the ultrasound field) via Langmuir-Blodgett experiments. Results from this study show a significant decrease ( p < 0.0001) in the nanobubble equilibrium surface tension through the incorporation of Pluronic L10, especially at a ratio of 0.2, where this value decreased by 28%. However, this reduction in surface pressure was seen only for specific compositions and varied with monolayer structure (crystalline phase or liquid-crystalline packing). These results indicate a potential for optimization wherein surface pressure can be maximized for both contraction and expansion phases with the proper lipid to Pluronic balance and microstructure.