Association Between Markers of Structural Racism and Mass Shooting Events in Major US Cities

Importance

The root cause of mass shooting events (MSEs) and the populations most affected by them are poorly understood.

Objective

To examine the association between structural racism and mass shootings in major metropolitan cities in the United States.

Design, Setting, and Participants

This cross-sectional study of MSEs in the 51 largest metropolitan statistical areas (MSAs) in the United States analyzes population-based data from 2015 to 2019 and the Gun Violence Archive. The data analysis was performed from February 2021 to January 2022.

Exposure

Shooting event where 4 or more people not including the shooter were injured or killed.

Main Outcome and Measures

MSE incidence and markers of structural racism from demographic data, Gini income coefficient, Black-White segregation index, and violent crime rate.

Results

There were 865 MSEs across all 51 MSAs from 2015 to 2019 with a total of 3968 injuries and 828 fatalities. Higher segregation index (ρ = 0.46, P = .003) was associated with MSE incidence (adjusted per 100 000 population) using Spearman ρ analysis. Percentage of the MSA population comprising Black individuals (ρ = 0.76, P < .001), children in a single-parent household (ρ = 0.44, P < .001), and violent crime rate (ρ = 0.34, P = .03) were other variables associated with MSEs. On linear regression, structural racism, as measured by percentage of the MSA population comprising Black individuals, was associated with MSEs (β = 0.10; 95% CI, 0.05 to 0.14; P < .001). Segregation index (β = 0.02, 95% CI, -0.03 to 0.06; P = .53), children in a single-parent household (β = -0.04, 95% CI, -0.11 to 0.04; P = .28), and Gini income coefficient (β = -1.02; 95% CI, -11.97 to 9.93; P = .93) were not associated with MSEs on linear regression.

Conclusions and Relevance

This study found that major US cities with higher populations of Black individuals are more likely to be affected by MSEs, suggesting that structural racism may have a role in their incidence. Public health initiatives aiming to prevent MSEs should target factors associated with structural racism to address gun violence.

Metabolic impact of high lipid low dextrose parenteral nutrition

BACKGROUND

Parenteral nutrition (PN) containing 100% soybean oil lipids and high amounts of dextrose may lead to liver dysfunction and hyperglycemia. Mixed lipids have less pro-inflammatory components, so higher doses may be given to decrease the amount of dextrose provided. The purpose of this study is to provide a descriptive analysis of patients who received PN with high mixed lipid and low dextrose content versus PN with lower 100% soybean oil lipid and high dextrose content.

METHODS

We retrospectively reviewed 62 patients aged ≥18 years receiving PN ≥ 7 days from 2016 to 2021 in an acute care hospital. Participants were divided into two groups: high lipid low dextrose (HLLD) containing a four-oil lipid (>30% kcal or ≥1 g/kg) vs adequate lipid high dextrose (ALHD) containing a 100% soybean oil lipid (<30% kcal or <1 g/kg SO-ILE).

RESULTS

Patients in the HLLD group (n = 31) had 64.1% lower incidence of blood glucose levels >180 mg/dL, decreased insulin requirements, 52.7% lower alkaline phosphatase levels, 40.6% higher prealbumin levels, and 42.6% lower c-reactive protein levels while maintaining similar calorie targets compared to the ALHD group (n = 31).

CONCLUSION

Changing from 100% soybean oil to a mixed lipid in PN is helpful to reduce soybean oil intake. However, it is also important to increase the mixed lipid dose to decrease the amount of dextrose provided. PNs containing higher amounts of mixed lipids (40-45% kcal) with lower amounts of dextrose (20-30% kcal) may have clinical benefits that warrant further exploration.

High lipid, low dextrose parenteral nutrition allows patient to achieve nutritional autonomy: A case report

INTRODUCTION

Prolonged use of parenteral nutrition can eventually lead to liver abnormalities. Causative factors include decreased enteral stimulation, high intakes of intravenous dextrose, proinflammatory 100 % soybean oil-based lipids, and increased burden on liver through 24-h infusions. We present a case report of a patient who received parenteral nutrition modifications to address liver dysfunction.

PRESENTATION OF CASE

Our patient was a 37-year-old African American male with a past medical history including refractory Crohn's disease complicated by multiple small bowel obstructions, several bowel surgeries, left lower quadrant colostomy placement, short bowel syndrome, severe protein calorie malnutrition, parenteral nutrition dependence, and elevated liver function tests. He was admitted for nutritional optimization before a planned takedown of multiple chronic enterocutaneous and perianal fistulas. His home parenteral nutrition order contained high amounts of dextrose (69 % kcal), and low amounts of 100 % soybean oil (11 % kcal).

DISCUSSION

Due to an elevated alkaline phosphatase level at baseline (1746 U/L), the Registered Dietitian maximized protein, decreased the dextrose by 62.5 %, and changed to SMOFlipid (a fish-oil containing lipid) at >1 g/kg/day to address liver abnormalities. Within 1.5 months of changing parenteral nutrition to high SMOFlipid (>30 % kcal) with low dextrose (<30 % kcal) content, alkaline phosphatase levels declined by 62 %, prealbumin levels increased by 56 %, and c-reactive protein levels decreased by 62 %.

CONCLUSION

Parenteral nutrition modifications led to reversal of chronic liver dysfunction. This patient ultimately underwent a successful high-risk fistula takedown procedure, allowing for complete weaning of parenteral nutrition and achievement of sustained nutritional autonomy.

Cost-Effectiveness of Universal Screening for Blunt Cerebrovascular Injury: A Markov Analysis

BACKGROUND

Blunt cerebrovascular injury (BCVI) is a significant cause of morbidity and mortality after blunt trauma. Numerous screening strategies exist, although which is used is institution- and physician-dependent. We sought to identify the most cost-effective screening strategy for BCVI, hypothesizing that universal screening would be optimal among the screening strategies studied.

STUDY DESIGN

A Markov decision analysis model was used to compare the following screening strategies for identification of BCVI: (1) no screening; (2) Denver criteria; (3) extended Denver criteria; (4) Memphis criteria; and (5) universal screening. The base-case scenario modeled 50-year-old patients with blunt traumatic injury excluding isolated extremity injures. Patients with BCVI detected on imaging were assumed to be treated with antithrombotic therapy, subsequently decreasing risk of stroke and mortality. One-way sensitivity analyses were performed on key model inputs. A single-year horizon was used with an incremental cost-effectiveness ratio threshold of $100,000 per quality-adjusted life-year.

RESULTS

The most cost-effective screening strategy for patients with blunt trauma among the strategies analyzed was universal screening. This method resulted in the lowest stroke rate, mortality, and cost, and highest quality-adjusted life-year. An estimated 3,506 strokes would be prevented annually as compared with extended Denver criteria (incremental cost-effectiveness ratio of $71,949 for universal screening vs incremental cost-effectiveness ratio of $12,736 for extended Denver criteria per quality-adjusted life-year gained) if universal screening were implemented in the US. In 1-way sensitivity analyses, universal screening was the optimal strategy when the incidence of BCVI was greater than 6%.

CONCLUSIONS

This model suggests universal screening may be the cost-effective strategy for BCVI screening in blunt trauma for certain trauma centers. Trauma centers should develop institutional protocols that take into account individual BCVI rates.

I text for I COUGH: A clinical pilot study to evaluate the impact of text messaging upon postoperative ambulation in the hospital

BACKGROUND

The "I COUGH" protocol is associated with improved postoperative pulmonary outcomes, and ambulation is an essential component. I COUGH is an acronym for Incentive spirometry, Coughing, Oral care, Understanding (patient and staff education), Getting-out-of-bed, and Head-of-bed elevation. This trial sought to enhance one component, specifically ambulation after operations.

METHODS

Randomized trial of inpatients in a safety-net, academic medical center. The intervention group received standard I COUGH education along with text message reminders to ambulate postoperatively, whereas the control group received standard education alone. Postoperative walking frequency was compared to each participant's ambulation on the day prior to enrollment.

RESULTS

The intervention group had an average improvement of 1.8 ± 1.8 walks per day per patient, while the average change for the control group was 0.2 ± 1.0 walks per day per patient. This represents a 9-fold increase in ambulation for the intervention group (p = 0.03).

CONCLUSIONS

Implementation of text message reminders increased ambulation and improved adherence to the I COUGH protocol following operations. This system should be further investigated as an adjunct to postoperative care.

Establishment and cryptic transmission of Zika virus in Brazil and the Americas

Transmission of Zika virus (ZIKV) in the Americas was first confirmed in May 2015 in northeast Brazil. Brazil has had the highest number of reported ZIKV cases worldwide (more than 200,000 by 24 December 2016) and the most cases associated with microcephaly and other birth defects (2,366 confirmed by 31 December 2016). Since the initial detection of ZIKV in Brazil, more than 45 countries in the Americas have reported local ZIKV transmission, with 24 of these reporting severe ZIKV-associated disease. However, the origin and epidemic history of ZIKV in Brazil and the Americas remain poorly understood, despite the value of this information for interpreting observed trends in reported microcephaly. Here we address this issue by generating 54 complete or partial ZIKV genomes, mostly from Brazil, and reporting data generated by a mobile genomics laboratory that travelled across northeast Brazil in 2016. One sequence represents the earliest confirmed ZIKV infection in Brazil. Analyses of viral genomes with ecological and epidemiological data yield an estimate that ZIKV was present in northeast Brazil by February 2014 and is likely to have disseminated from there, nationally and internationally, before the first detection of ZIKV in the Americas. Estimated dates for the international spread of ZIKV from Brazil indicate the duration of pre-detection cryptic transmission in recipient regions. The role of northeast Brazil in the establishment of ZIKV in the Americas is further supported by geographic analysis of ZIKV transmission potential and by estimates of the basic reproduction number of the virus.

High-performance liquid chromatography multiplex detection of two single nucleotide mutations associated with hereditary hemochromatosis

High-performance liquid chromatography (HPLC) has been applied to the multiplex detection of the two single nucleotide mutations commonly found in hereditary hemochromatosis (HH). HH is associated with a major G to A transition at position 845 (mutation Cys282Tyr) and a minor C to G transition at position 187 (mutation His63Asp) in the cDNA of the HFE gene. Two detection assays were developed based on HPLC analysis of restriction fragment length polymorphism (RFLP) or single nucleotide extension (SNE) products following multiplex PCR amplification. RFLP genotypes the two sites as dsDNA fragments of different lengths generated by restriction enzymes Rsa I/Bcl I. SNE extends primers 5'-adjacent to the sites of interest with a dideoxynucleotide triphosphate (ddNTP) to generate extended ssDNA. The identity of the added ddNTP reveals the identity of the original possible mutation site(s). Application of these methods with HPLC analysis provides simple and reliable genotyping for HH and can be applied to other single nucleotide polymorphism studies.

Detection of hemochromatosis through the analysis of single- nucleotide extension products by capillary electrophoresis

Hereditary hemochromatosis is one of the most common hereditary disorders in Caucasians.The disease is linked to two single-nucleotide polymorphisms (SNPs) in the HFE gene.The two point mutations result in a change of Cys to Tyr at position 282 and His to Asp at position 63 in the resultant protein.We have developed a single-nucleotide extension (SNE) assay for hereditary hemochromatosis genetic testing, which employs capillary electrophoresis to simultaneously detect the SNE products generated from the two SNP sites. An upstream or a downstream primer adjacent to the possible mutation site is designed and extended one nucleotide further at the 3' end, complementary to the nucleotide at the possible mutation site.The extended nucleotide is one of four fluorescently labeled dideoxynucleotide triphosphates that also act as terminators. Analysis of the extended products by laser-induced fluorescence capillary electrophoresis (LIF-CE) directly reflects the identity of the possible mutation site. Using one primer upstream or downstream from the possible mutation site, three genotypes at one mutation site can be distinguished. Using both upstream and downstream primers provides a second level of specificity and increases the accuracy of the genetic test. The protocol can also be applied to the study of other SNP analyses and to simultaneous detection of multiple mutation sites.

Regulation of transforming growth factor beta1 by nitric oxide

Many tumor cells or their secreted products suppress the function of tumor-infiltrating macrophages. Tumor cells often produce abundant transforming growth factor beta1 (TGF-beta1), which in addition to other immunosuppressive actions suppresses the inducible isoform of NO synthase. TGF-beta1 is secreted in a latent form, which consists of TGF-beta1 noncovalently associated with latency-associated peptide (LAP) and which can be activated efficiently by exposure to reactive oxygen species. Coculture of the human lung adenocarcinoma cell line A549 and ANA-1 macrophages activated with IFN-gamma plus lipopolysaccharide resulted in increased synthesis and activation of latent TGF-beta1 protein by both A549 and ANA-1 cells, whereas unstimulated cultures of either cell type alone expressed only latent TGF-beta1. We investigated whether exposure of tumor cells to NO influences the production, activation, or activity of TGF-beta1.A549 human lung adenocarcinoma cells exposed to the chemical NO donor diethylamine-NONOate showed increased immunoreactivity of cell-associated latent and active TGF-beta1 in a time- and dose-dependent fashion at 24-48 h after treatment. Exposure of latent TGF-beta1 to solution sources of NO neither led to recombinant latent TGF-beta1 activation nor modified recombinant TGF-beta1 activity. A novel mechanism was observed, however: treatment of recombinant LAP with NO resulted in its nitrosylation and interfered with its ability to neutralize active TGF-beta1. These results provide the first evidence that nitrosative stress influences the regulation of TGF-beta1 and raise the possibility that NO production may augment TGF-beta1 activity by modifying a naturally occurring neutralizing peptide.

Aldose reductase catalyzes the oxidation of naphthalene-1, 2-dihydrodiol for the formation of ortho-naphthoquinone

The oxidation of naphthalene-1,2-dihydrodiol (ND) to o-naphthoquinone (NQ) in the lens is believed to be responsible for the formation of cataracts in naphthalene-fed rats. Studies using either recombinant rat lens (RLAR) or human muscle aldose reductase (HMAR) incubated in vitro with ND in the presence of NAD(P) verified that aldose reductase (EC 1.1.1.21) is the dihydrodiol dehydrogenase that catalyzes the oxidation of ND to NQ. Kinetic studies of Vmax/Km indicated that RLAR catalyzes the NAD-dependent oxidation of ND with an optimal pH of 9.0. The corresponding activity of HMAR was lower than that of rat enzyme. The metabolite produced by the incubation of RLAR with ND in the presence of 2-mercaptoethanol and NAD in 20 mM phosphate buffer, pH 7.5, was isolated by C18 reversed-phase high-performance liquid chromatography. The elution profile showed the formation of a new peak that was identical with a peak generated when NQ was incubated under the same condition. The metabolite in both peaks was identified as 4-(2-hydroxyethylsulfanyl)-1, 2-dihydro-1,2-naphthalenedione (HNQ) by 1H and 13C NMR analyses using homonuclear correlation spectroscopy, heteronuclear multiple quantum coherence, and heteronuclear shift correlations via multiple bond connectivities as well as infrared analysis. HNQ is readily autoxidized to 2,3-dihydro-1-oxa-4-thia-9,10-phenanthrenedione. The stoichiometry of 1:1 between the consumption of ND and the formation of NADH for the formation of HNQ implies that rat lens aldose reductase catalyzes a 2e- oxidation of ND to yield the corresponding ketol, which is autoxidized to NQ.

Facile oxidative decarboxylation of 3,4-dihydroxyphenylacetic acid catalyzed by copper and manganese ions

Under physiological conditions, we observed the rapid, pH- and temperature-dependent, oxidative decarboxylation and hydration of 3,4-dihydroxyphenylacetic acid (DOPAC) to form 3,4-dihydroxybenzyl alcohol (DBAlc). This product was oxidized and underwent tautomerization to form 3,4-dihydroxybenzaldehyde (DBAld). This reaction did not occur in the presence of EDTA, was catalyzed by copper (CuI, CuII) and manganese (MnII) and was oxygen dependent. A variety of mono- and dihydroxyphenyl carboxylic acids were tested and the reaction producing DBAlc as an intermediate was observed to be unique to DOPAC. 3.4-Dihydroxymandelic acid (DOMA) was rapidly oxidatively decarboxylated to form DBAld directly. The substrate and catalyst selectivity of this reaction suggest that this may have physiological relevance in the neurotoxic consequences of manganese and copper to the dopaminergic system in man.

Analysis of amino acids in biological fluids by pentafluorobenzyl chloroformate derivatization and detection by electron capture negative ionization mass spectrometry

Pentafluorobenzyl chloroformate (PFBCF) has been utilized as a derivatization reagent for amino acids (AAs) in biological fluids with susequent detection by electron capture negative ionization mass spectrometry (ECNI/MS). AAs were derivatized in one step in aqueous solution, plasma, and whole blood at room temperature. To demonstrate quantitative analysis, phenylalanine concentrations were determined in human plasma. AAs were derivatized in one step using PFBCF and a mixture of water, ethanol, and pyridine/dimethylaminopyridine. The N-pentafluorobenzyloxycarbonyl amino acid ethyl esters (f phi-AA-OEt) exhibited good GC properties and the ECNI mass spectra are dominated by the [M-181]- ion. The f phi-AA-OEt derivatives can be easily detected at the femtomole level by selected ion monitoring. Phenethyl alcohol was also derivatized, using anhydrous conditions, and the resulting PFB carbonate's ECNI mass spectrum was dominated by the [M-181]- ion. The ECNI molar response of the PFB carbonate derivative is two times that of the corresponding pentafluorobenzoate.

Pentafluorobenzyl chloroformate derivatization for enhancement of detection of amino acids or alcohols by electron capture negative ion chemical ionization mass spectrometry

Pentafluorobenzyl chloroformate (PFB-chloroformate) has been utilized as a derivatization reagent to impart electron affinity and provide structurally relevant fragmentation in electron capture negative ion chemical ionization mass spectrometry (ECNICI-MS). Phenylalanine (Phe) and decanol were used as model analytes. The conditions used for their derivatization and the chromatographic and mass spectrometric properties of the derivatives are reported. Phenylalanine in aqueous solution was derivatized in one step by using PFB-chloroformate and a mixture of water, ethanol, and pyridine. The phenylalanine N-pentafluorobenzyl-oxycarbonyl ethyl ester (N-PFBC-Phe-OEt) exhibited good gas chromatographic properties and in ECNICI-MS, a dominant [M - 181](-) fragment carries most of the ion current. Selected ion monitoring experiments on N-PFBC-Phe-OEt resulted in the facile detection of 400 fmol of material. Decanol was derivatized by using anhydrous conditions, and the resultant pentafluorobenzyl carbonate also exhibited a predominant [M - 181](-) ion in ECNICI-MS. Initial results indicate that the ECNICI-MS molar response of the decyl pentafluorobenzyl carbonate derivative is six-fold that of the decyl pentafluorobenzoate.

Characterization of anthraquinone-2-carbonyl chloride as an alcohol derivatization reagent for negative ion chemical ionization mass spectrometry

Anthraquinone-2-carbonyl chloride has been utilized as a derivatization reagent for alcohols to impart electron affinity and aid in transport via a particle beam liquid chromatography-mass spectrometry (LC/MS) interface. In addition, the gas chromatographic-mass spectrometry, UV, fluorescence, and electrochemical characteristics of the derivatives were determined. A series of model compounds, 2-phenylethanol (phenethyl alcohol), 1-phenyl-2-propanol, 2-methyl-l-phenyl-2-propanol, hexanol, and methyl 2-methylglycerate, were used as analytes.The particle beam LC/MS properties of the resultant anthraquinone carboxylate esters were determined in electron impact (EI) and negative ion chemical ionization (NCI) modes. The NCI responses of these anthraquinone carboxylate esters were compared with the corresponding 3,5-dinitrobenzoate esters. The anthraquinone carboxylate esters exhibited an NCI to EI sensitivity enhancement of 113 and were detected in NCI at a tenfold lower concentration than the corresponding 3,5-dinitrobenzoate esters. A detection limit of 26 pg injected on column was achieved for phenethyl anthraquinone carboxylate in NCI by using selected ion monitoring.

Quantification of L-tryptophan and L-kynurenine by liquid chromatography/electron capture negative ion chemical ionization mass spectrometry

In a number of infectious and inflammatory diseases, stimulation of the immune system can lead to increased accumulation of tryptophan metabolites via induction of kynurenine pathway enzymes in extrahepatic tissues. We developed a liquid chromatographic/mass spectrometric (LC/MS) method suitable for tracing the disposition of 13C isotopomers of L-tryptophan and L-kynurenine in various cultured cell, tissue slice, and whole animal model systems used to investigate tryptophan flux through the kynurenine pathway. The method employs extractive derivatization of the analytes and their 2H internal standards with pentafluorobenzyl bromide in order to enhance the negative ion chemical ionization (NICI) mass spectrometric response. Normal-phase liquid chromatographic separation of derivatized analytes was optimized using a silica column with organic solvents, followed by particle beam transfer and NICI-MS. Standard curves were linear over the range 1-250 ng per sample. Particle beam and mass spectrometric operating parameters were optimized with direct flow injections of 1-(methylamino) anthraquinone, which is an ideal test compound for the evaluation of LC/NICI-MS. The developed method was used to quantify the conversion of (13C6)L-tryptophan to (13C6)L-kynurenine by human monocytes (THP-1) stimulated with interferon-gamma, lung and brain tissue slices obtained from gerbils immune-stimulated with pokeweed mitogen. The effect of whole body immune stimulation on the plasma levels of endogenous L-kynurenine in mice stimulated with interferon-gamma was also quantified.

Interaction of trichloromethyl free radicals with thymine in a model system: a mass spectrometric study

In previous studies from our laboratory we found that the CCl4 reactive metabolites produced during enzymatic in vitro or in vivo CCl4 biotransformation covalently bind to DNA. Further, chemically produced.CCl3 produce many adducts of unknown structure with the four DNA bases when the reaction proceeds in model systems. In the present work, we describe our attempt to elucidate by GLC/MS the structures of the adducts resulting when chemically generated.CCl3 interact with thymine. The following reaction products were identified: (i) 5-hydroxymethyl uracil; (ii) thymineglycol; (iii) 5-trichloroethyl uracil (tentative) and (iv) two isomeric 5,6-monochloro monohydroxy adducts of thymine (tentative). Reaction products found do not involve thymine positions directly participating in base-pairing processes. However, alterations in thymine structure reported if they occurred in DNA from livers of CCl4 poisoned animals, might potentially have biological significance that remains to be established.

Anandamide, an endogenous cannabimimetic eicosanoid, binds to the cloned human cannabinoid receptor and stimulates receptor-mediated signal transduction

Arachidonylethanolamide (anandamide), a candidate endogenous cannabinoid ligand, has recently been isolated from porcine brain and displayed cannabinoid-like binding activity to synaptosomal membrane preparations and mimicked cannabinoid-induced inhibition of the twitch response in isolated murine vas deferens. In this study, anandamide and several congeners were evaluated as cannabinoid agonists by examining their ability to bind to the cloned cannabinoid receptor, inhibit forskolin-stimulated cAMP accumulation, inhibit N-type calcium channels, and stimulate one or more functional second messenger responses. Synthetic anandamide, and all but one congener, competed for [3H]CP55,940 binding to plasma membranes prepared from L cells expressing the rat cannabinoid receptor. The ability of anandamide to activate receptor-mediated signal transduction was evaluated in Chinese hamster ovary (CHO) cells expressing the human cannabinoid receptor (HCR, termed CHO-HCR cells) and compared to control CHO cells expressing the muscarinic m5 receptor (CHOm5 cells). Anandamide inhibited forskolin-stimulated cAMP accumulation in CHO-HCR cells, but not in CHOm5 cells, and this response was blocked with pertussis toxin. N-type calcium channels were inhibited by anandamide and several active congeners in N18 neuroblastoma cells. Anandamide stimulated arachidonic acid and intracellular calcium release in both CHOm5 and CHO-HCR cells and had no effect on the release of inositol phosphates or phosphatidylethanol, generated after activation of phospholipase C and D, respectively. Anandamide appears to exhibit the essential criteria required to be classified as a cannabinoid/anandamide receptor agonist and shares similar nonreceptor effects on arachidonic acid and intracellular calcium release as other cannabinoid agonists.

Identification of major lipids from the scent gland secretions of Dumeril's ground boa (Acrantophis dumerili Jan) by gas chromatography-mass spectrometry

The scent gland secretions of Dumeril's ground boa (Acrantophis dumerili), pooled from two adult males and a female, were analyzed by gas chromatography-mass spectrometry. 2-Hydroxy-propanoic acid, hexadecanoic acid, cis-9-octadecenoic acid, octadecanoic acid, cholesterol, and 5-cholesten-3-one were indicated. These results are compared with those obtained in analyses of the scent gland secretions of other snakes.