County-Level Socio-Environmental Factors Associated With Stroke Mortality in the United States: A Cross-Sectional Study.

We used machine learning methods to explore sociodemographic and environmental determinants of health (SEDH) associated with county-level stroke mortality in the USA. We conducted a cross-sectional analysis of individuals aged ≥15 years who died from all stroke subtypes between 2016 and 2020. We analyzed 54 county-level SEDH possibly associated with age-adjusted stroke mortality rates/100,000 people. Classification and Regression Tree (CART) was used to identify specific county-level clusters associated with stroke mortality. Variable importance was assessed using Random Forest analysis. A total of 501,391 decedents from 2397 counties were included. CART identified 10 clusters, with 77.5% relative increase in stroke mortality rates across the spectrum (28.5 vs 50.7 per 100,000 persons). CART identified 8 SEDH to guide the classification of the county clusters. Including, annual Median Household Income ($), live births with Low Birthweight (%), current adult Smokers (%), adults reporting Severe Housing Problems (%), adequate Access to Exercise (%), adults reporting Physical Inactivity (%), adults with diagnosed Diabetes (%), and adults reporting Excessive Drinking (%). In conclusion, SEDH exposures have a complex relationship with stroke. Machine learning approaches can help deconstruct this relationship and demonstrate associations that allow improved understanding of the socio-environmental drivers of stroke and development of targeted interventions.

Medical and Personal Characteristics Can Predict the Risk of Lung Metastasis.

AIMS: Understanding the correlations between underlying medical and personal characteristics of a patient with cancer and the risk of lung metastasis may improve clinical management and outcomes. We used machine learning methodologies to predict the risk of lung metastasis using readily available predictors. MATERIALS AND METHODS: We retrospectively analysed a cohort of 11 164 oncological patients, with clinical records gathered between 2000 and 2020. The input data consisted of 94 parameters, including age, body mass index (BMI), sex, social history, 81 primary cancer types, underlying lung disease and diabetes mellitus. The strongest underlying predictors were discovered with the analysis of the highest performing method among four distinct machine learning methods. RESULTS: Lung metastasis was present in 958 of 11 164 oncological patients. The median age and BMI of the study population were 63 (±19) and 25.12 (±5.66), respectively. The random forest method had the most robust performance among the machine learning methods. Feature importance analysis revealed high BMI as the strongest predictor. Advanced age, smoking, male gender, alcohol dependence, chronic obstructive pulmonary disease and diabetes were also strongly associated with lung metastasis. Among primary cancers, melanoma and renal cancer had the strongest correlation. CONCLUSIONS: Using a machine learning-based approach, we revealed new correlations between personal and medical characteristics of patients with cancer and lung metastasis. This study highlights the previously unknown impact of predictors such as obesity, advanced age and underlying lung disease on the occurrence of lung metastasis. This prediction model can assist physicians with preventive risk factor control and treatment strategies.

Basilar artery curvature is associated with migraine with aura in the Northern Manhattan Study.

INTRODUCTION: Genetic and imaging studies demonstrate a link between vascular morphology and migraine with aura (MA). We examined the relationship between basilar artery (BA) curvature and MA in a population-based cohort of stroke-free participants. METHODS: This cross-sectional study included participants from the MRI substudy of the Northern Manhattan Study. Participants had structured migraine assessments at enrollment and underwent brain MR angiography. BA curvature was defined as the sum of the total BA horizontal deviation from midline at the distal tip, mid-pons, and vertebrobasilar junction, and was the primary independent variable in logistic regression analyses. BA measurements were obtained blinded to migraine status. We compared groups of all migraine vs no migraine, migraine without aura (MwoA) vs no migraine, and MA vs no migraine. RESULTS: Of 880 participants, 146 had MwoA and 32 had MA. Average BA curvatures were 15.2 ± 8.9 mm in non-migraineurs, 15.8 ± 9.3 mm in MwoA, and 18.5 ± 11.4 mm in MA. In an adjusted model, greater BA curvature was associated with MA (OR 1.042 per mm, 95% CI 1.006-1.080) but not with MwoA (OR 1.014 per mm, 95% CI 0.993-1.035), when compared to non-migraineurs. CONCLUSIONS: Greater BA curvature was associated with MA. Given aura typically originates from the occipital cortex, understanding the physiopathology of this association may provide clues to migraine's underlying mechanisms and relationship with stroke.

Clinical Impact of Thrombophilia Screening in Young Adults with Ischemic Stroke.

OBJECTIVE: We evaluated the ability of genetic and serological testing to diagnose clinically relevant thrombophilias in young adults with ischemic stroke. METHODS: We performed a retrospective cohort study of patients aged 18-65 years diagnosed with acute ischemic stroke at a comprehensive stroke center between 2011 and 2015 with laboratory testing for thrombophilia. The primary outcome was any positive thrombophilia screening test. The secondary outcome was a change in clinical management based on thrombophilia testing results. Logistic regression was used to assess whether the prespecified risk factors of age, sex, prior venous thromboembolism, family history of stroke, stroke subtype, and presence of patent foramen ovale were associated with outcomes. RESULTS: Among 196 young ischemic stroke patients, at least 1 positive thrombophilia test was identified in 85 patients (43%; 95% CI, 36%-51%) and 16 (8%; 95% CI, 5%-13%) had a resultant change in management. Among 111 patients with cryptogenic strokes, 49 (44%) had an abnormal thrombophilia test and 9 (8%) had a change in management. After excluding cases of isolated hyperhomocysteinemia or methylenetetrahydrofolate reductase or Factor V Leiden gene mutation heterozygosity, the proportion of patients with an abnormal thrombophilia screen decreased to 24%. Prespecified risk factors were not significantly associated with positive thrombophilia testing or a change in management. CONCLUSIONS: Two-of-five young patients with ischemic stroke who underwent thrombophilia screening at our institution had at least 1 positive test but only one-in-twelve had a resultant change in clinical management. Neither cryptogenic stroke subtype nor other studied clinical factors were associated with a prothrombotic state.

A rapid introduction to neurological biochemistry using Drosophila melanogaster.

Short, cost-effective teaching activities are a useful way of providing an integrated view on biological processes. Here we describe a brief, hands-on workshop that allows pre-university students to explore their understanding of a neurological pathway from its chemical bases to phenotype. The workshop effectively introduces the students to data collection and analysis in an enjoyable way and at an appropriate level, determined by an end of session feedback survey. The design of the workshop can be adapted and scaled to generate diverse sessions such as university teaching practicals or summer school training workshops.

Comparative Risks of Ischemic Stroke in Atrial Flutter versus Atrial Fibrillation.

INTRODUCTION: The aim of this study was to compare the risk of ischemic stroke in patients who have atrial fibrillation and patients who have atrial flutter. METHODS: Using inpatient and outpatient Medicare claims data from 2008 to 2014 for a 5% sample of all beneficiaries 66 years of age or older, we identified patients diagnosed with atrial fibrillation and those diagnosed with atrial flutter. The primary outcome was ischemic stroke. In the primary analysis, patients with atrial flutter were censored upon converting to fibrillation; in a secondary analysis, they were not. Survival statistics were used to compare incidence of stroke in patients with flutter and patients with fibrillation. Cox proportional hazards analysis was used to compare the associations of flutter and fibrillation with ischemic stroke after adjustment for demographics and risk factors. RESULTS: We identified 14,953 patients with flutter and 318,138 with fibrillation. During a mean follow-up period of 2.8 (±2.3) years, we identified 18,900 ischemic strokes. The annual incidence of ischemic stroke in patients with flutter was 1.38% (95% confidence interval [CI] 1.22%-1.57%) compared with 2.02% (95% CI 1.99%-2.05%) in patients with fibrillation. After adjustment for demographics and stroke risk factors, flutter was associated with a lower risk of stroke compared with fibrillation (hazard ratio .69; 95% CI .60-.79, P < .05). Within 1 year, 65.7% (95% CI 64.9%-66.4%) of patients with flutter converted to fibrillation but remained at a lower risk of ischemic stroke (hazard ratio .85; 95% CI .78-.92). CONCLUSIONS: Patients with atrial flutter faced a lower risk of ischemic stroke than patients with atrial fibrillation.

Homozygous missense mutation in fibulin-5 in an Iranian autosomal recessive cutis laxa pedigree and associated haplotype.

Cutis laxa is a rare group of inherited and acquired disorders characterized by loose and redundant skin with reduced elasticity. Mutations in the elastin coding gene have been shown to cause autosomal dominant cutis laxa in three families. A homozygous mutation in the fibulin-5 coding gene was discovered in a Turkish pedigree showing recessive inheritance, and a different mutation in this gene was found in the heterozygous state in a sporadic case of the disease. Here, we report the third case of a mutation in the fibulin-5 coding gene in a recessive Iranian cutis laxa pedigree. The mutation is the same as previously reported in the Turkish pedigree, further confirming that it is causative of disease. A haplotype consisting of seven intragenic sequence variations common to both pedigrees is described for the mutation-carrying fibulin-5 allele.

In vitro assays for kinetoplastid U insertion-deletion editing and associated activities.

This chapter describes biochemical assays that have been used in analyzing RNA editing in kinetoplastid mitochondria and to characterize the general mechanism of editing by the editosome. Studies using these assays have shown that the characteristics of each activity contribute to editing site selection, U addition and removal, and RNA ligation resulting in accurately edited mRNAs.

Separate insertion and deletion subcomplexes of the Trypanosoma brucei RNA editing complex.

The Trypanosoma brucei editosome catalyzes the maturation of mitochondrial mRNAs through the insertion and deletion of uridylates and contains at least 16 stably associated proteins. We examined physical and functional associations among these proteins using three different approaches: purification of complexes via tagged editing ligases TbREL1 and TbREL2, comprehensive yeast two-hybrid analysis, and coimmunoprecipitation of recombinant proteins. A purified TbREL1 subcomplex catalyzed precleaved deletion editing in vitro, while a purified TbREL2 subcomplex catalyzed precleaved insertion editing in vitro. The TbREL1 subcomplex contained three to four proteins, including a putative exonuclease, and appeared to be coordinated by the zinc finger protein TbMP63. The TbREL2 subcomplex had a different composition, contained the TbMP57 terminal uridylyl transferase, and appeared to be coordinated by the TbMP81 zinc finger protein. This study provides insight into the molecular architecture of the editosome and supports the existence of separate subcomplexes for deletion and insertion editing.

Dyskinetoplastic Trypanosoma brucei contains functional editing complexes.

Mitochondrial pre-mRNAs undergo posttranscriptional RNA editing as directed by small guide RNAs (gRNAs) to produce functional mRNAs in kinetoplastid protozoa. The pre-mRNAs and gRNAs are encoded in the maxicircle and minicircle components, respectively, of the kinetoplastid mitochondrial DNA (kDNA), and editing is catalyzed by a multienzyme protein complex. Trypanosoma evansi AnTat3/3, which lacks maxicircles but retains a single class of minicircles, and a dyskinetoplastic mutant of Trypanosoma brucei EATRO164, which is devoid of kDNA, were both shown to retain genes and proteins for the editing complex. The proteins are present in complexes that immunoprecipitate and sediment indistinguishably from wild-type complexes. The complexes catalyze precleaved insertion and deletion editing as well as full-round deletion editing in vitro. Thus, mutants which lack the natural substrates for RNA editing and all or most gRNAs retain editing complexes that contain the four primary catalytic activities of editing and function in editing, at least in vitro. Therefore neither pre-mRNA nor gRNA is required to form functional RNA-editing complexes.

TbMP44 is essential for RNA editing and structural integrity of the editosome in Trypanosoma brucei.

RNA editing produces mature mitochondrial mRNAs in trypanosomatids by the insertion and deletion of uridylates. It is catalyzed by a multiprotein complex, the editosome. We identified TbMP44 among the components of enriched editosomes by a combination of mass spectrometry and DNA sequence database analysis. Inactivation of an ectopic TbMP44 allele in cells in which the endogenous alleles were disrupted abolished RNA editing, inhibited cell growth, and was eventually lethal to bloodstream form trypanosomes. Loss of TbMP44 mRNA was followed initially by a reduction in the editosome sedimentation coefficient and then by the absence of other editosome proteins despite the presence of the mRNA. Reactivation of TbMP44 gene expression resulted in the resumption of cell growth and the reappearance of editosomes. These data indicate that TbMP44 is a component of the editosome that is essential for editing and critical for the structural integrity of the editosome.

Kinetoplastid RNA editing ligases: complex association, characterization, and substrate requirements.

RNA editing processes kinetoplastid mitochondrial transcripts post-transcriptionally by inserting and deleting uridylates (Us) to produce functional mRNAs. The activities of the RNA ligases in the multienzyme complex (the editosome) that catalyzes editing and of the recombinant proteins were characterized and found to be similar. Ligation of two RNA fragments was enhanced when bridged by a complementary RNA or DNA, which left no gaps or overhangs. An acceptor nucleotide preference of G>U>C>A was observed in the absence of exogenous ATP but U was preferred upon addition of ATP and ligase activity was increased. The substrate specificity and catalytic characteristics indicate that RNA ligase activity contributes to the accuracy of RNA editing.

TbMP81 is required for RNA editing in Trypanosoma brucei.

Most mitochondrial mRNAs are edited in Trypano soma brucei by a series of steps that are catalyzed by a multienzyme complex that is in its initial stages of characterization. RNA interference (RNAi)-mediated repression of the expression of TbMP81, a zinc finger protein component of the complex, inhibited growth of bloodstream and insect forms, and blocked in vivo RNA editing. This repression preferentially inhibited insertion editing compared with deletion editing in vitro. It resulted in reduced specific endoribonucleolytic cleavage and a greater reduction of U addition and associated RNA ligation activities than U removal and associated RNA ligation activities. The repressed cells retained 20S editing complexes with several demonstrable proteins and adenylatable TbMP52 RNA ligase, but adenlyatable TbMP48 was not detected. Elimination of TbMP48 by RNAi repression did not inhibit cell growth or in vivo editing in either bloodstream or procyclic forms. These results indicate that TbMP81 is required for RNA editing and suggest that the editing complex is functionally partitioned.

Endoribonuclease activities of Trypanosoma brucei mitochondria.

RNA editing in kinetoplastids is a type of post-transcriptional processing that changes mitochondrial mRNA sequences by the addition or deletion of uridines. Multiple enzymatic activities, such as endoribonuclease and RNA ligase, are associated with this process and exist in a multienzyme complex. Endonuclease activities from Trypanosoma brucei mitochondrial extracts were fractionated by sequential ion exchange and gel filtration chromatography. The RNA editing specific endonuclease activity co-fractionated with in vitro editing while another endonuclease activity with a different substrate specificity, and the majority of mtRNase P activity fractionated away from the editing activity. The pH, salt, temperature, and Mg(2+) optima of all three endonucleases were determined. All three activities are sensitive to high temperature and protease digestion. In addition, treatment with micrococcal nuclease resulted in partial disruption of the editing complex and decreased pre-cleaved in vitro insertion editing activity, suggesting that both RNA(s) and protein(s) are necessary in the intact functional complex.