Transcriptomic analysis of paired healthy human skeletal muscles to identify modulators of disease severity in DMD

Muscle damage and fibro-fatty replacement of skeletal muscles is a main pathologic feature of Duchenne muscular dystrophy (DMD) with more proximal muscles affected earlier and more distal affected later in the disease course, suggesting that different skeletal muscle groups possess distinctive characteristics that influence their susceptibility to disease. To explore transcriptomic factors driving differential gene expression and modulating DMD skeletal muscle severity, we characterized the transcriptome of vastus lateralis (VL), a more proximal and susceptible muscle, relative to tibialis anterior (TA), a more distal and protected muscle, in 15 healthy individuals using bulk RNA sequencing to identify gene expression differences that may mediate their relative susceptibility to damage with loss of dystrophin. Matching single nuclei RNA sequencing data was generated for 3 of the healthy individuals, to infer cell composition in the bulk RNA sequencing dataset and to improve mapping of differentially expressed genes to their cell source of expression. A total of 3,410 differentially expressed genes were identified and mapped to cell type using single nuclei RNA sequencing of muscle, including long non-coding RNAs and protein coding genes. There was an enrichment of genes involved in calcium release from the sarcoplasmic reticulum, particularly in the myofibers and these myofiber genes were higher in the VL. There was an enrichment of genes in "Collagen-Containing Extracellular Matrix" expressed by fibroblasts, endothelial, smooth muscle and pericytes, with most genes higher in the TA, as well as genes in "Regulation Of Apoptotic Process" expressed across all cell types. Previously reported genetic modifiers were also enriched within the differentially expressed genes. We also identify 6 genes with differential isoform usage between the VL and TA. Lastly, we integrate our findings with DMD RNA sequencing data from the TA, and identify "Collagen-Containing Extracellular Matrix" and "Negative Regulation Of Apoptotic Process" as differentially expressed between DMD compared to healthy. Collectively, these findings propose novel candidate mechanisms that may mediate differential muscle susceptibility in muscular dystrophies and provide new insight into potential therapeutic targets.

Expression of SRP-9001 dystrophin and stabilization of motor function up to 2 years post-treatment with delandistrogene moxeparvovec gene therapy in individuals with Duchenne muscular dystrophy

Introduction: Delandistrogene moxeparvovec (SRP-9001) is an investigational gene transfer therapy designed for targeted expression of SRP-9001 dystrophin protein, a shortened dystrophin retaining key functional domains of the wild-type protein. Methods: This Phase 2, double-blind, two-part (48 weeks per part) crossover study (SRP-9001-102 [Study 102]; NCT03769116) evaluated delandistrogene moxeparvovec in patients, aged ≥4 to <8 years with Duchenne muscular dystrophy. Primary endpoints (Part 1) were change from baseline (CFBL) in SRP-9001 dystrophin expression (Week 12), by Western blot, and in North Star Ambulatory Assessment (NSAA) score (Week 48). Safety assessments included treatment-related adverse events (TRAEs). Patients were randomized and stratified by age to placebo (n = 21) or delandistrogene moxeparvovec (n = 20) and crossed over for Part 2. Results: SRP-9001 dystrophin expression was achieved in all patients: mean CFBL to Week 12 was 23.82% and 39.64% normal in Parts 1 and 2, respectively. In Part 1, CFBL to Week 48 in NSAA score (least-squares mean, LSM [standard error]) was +1.7 (0.6) with treatment versus +0.9 (0.6) for placebo; p = 0.37. Disparity in baseline motor function between groups likely confounded these results. In 4- to 5-year-olds with matched baseline motor function, CFBL to Week 48 in NSAA scores was significantly different (+2.5 points; p = 0.0172), but not significantly different in 6-to-7-year-olds with imbalanced baseline motor function (-0.7 points; p = 0.5384). For patients treated with delandistrogene moxeparvovec in Part 2, CFBL to Week 48 in NSAA score was +1.3 (2.7), whereas for those treated in Part 1, NSAA scores were maintained. As all patients in Part 2 were exposed to treatment, results were compared with a propensity-score-weighted external control (EC) cohort. The LSM difference in NSAA score between the Part 2 treated group and EC cohort was statistically significant (+2.0 points; p = 0.0009). The most common TRAEs were vomiting, decreased appetite, and nausea. Most occurred within the first 90 days and all resolved. Discussion: Results indicate robust expression of SRP-9001 dystrophin and overall stabilization in NSAA up to 2 years post-treatment. Differences in NSAA between groups in Part 1 were not significant for the overall population, likely because cohorts were stratified only by age, and other critical prognostic factors were not well matched at baseline.

SPTSSA variants alter sphingolipid synthesis and cause a complex hereditary spastic paraplegia

Sphingolipids are a diverse family of lipids with critical structural and signalling functions in the mammalian nervous system, where they are abundant in myelin membranes. Serine palmitoyltransferase, the enzyme that catalyses the rate-limiting reaction of sphingolipid synthesis, is composed of multiple subunits including an activating subunit, SPTSSA. Sphingolipids are both essential and cytotoxic and their synthesis must therefore be tightly regulated. Key to the homeostatic regulation are the ORMDL proteins that are bound to serine palmitoyltransferase and mediate feedback inhibition of enzymatic activity when sphingolipid levels become excessive. Exome sequencing identified potential disease-causing variants in SPTSSA in three children presenting with a complex form of hereditary spastic paraplegia. The effect of these variants on the catalytic activity and homeostatic regulation of serine palmitoyltransferase was investigated in human embryonic kidney cells, patient fibroblasts and Drosophila. Our results showed that two different pathogenic variants in SPTSSA caused a hereditary spastic paraplegia resulting in progressive motor disturbance with variable sensorineural hearing loss and language/cognitive dysfunction in three individuals. The variants in SPTSSA impaired the negative regulation of serine palmitoyltransferase by ORMDLs leading to excessive sphingolipid synthesis based on biochemical studies and in vivo studies in Drosophila. These findings support the pathogenicity of the SPTSSA variants and point to excessive sphingolipid synthesis due to impaired homeostatic regulation of serine palmitoyltransferase as responsible for defects in early brain development and function.

Continuing a search for a diagnosis: the impact of adolescence and family dynamics

The "diagnostic odyssey" describes the process those with undiagnosed conditions undergo to identify a diagnosis. Throughout this process, families of children with undiagnosed conditions have multiple opportunities to decide whether to continue or stop their search for a diagnosis and accept the lack of a diagnostic label. Previous studies identified factors motivating a family to begin searching, but there is limited information about the decision-making process in a prolonged search and how the affected child impacts a family's decision. This study aimed to understand how families of children with undiagnosed diseases decide whether to continue to pursue a diagnosis after standard clinical testing has failed. Parents who applied to the Undiagnosed Disease Network (UDN) at the National Institutes of Health (NIH) were recruited to participate in semi-structured interviews. The 2015 Supportive Care Needs model by Pelenstov, which defines critical needs in families with rare/undiagnosed diseases, provided a framework for interview guide development and transcript analysis (Pelentsov et al in Disabil Health J 8(4):475-491, 2015. https://doi.org/10.1016/J.DHJO.2015.03.009 ). A deductive, iterative coding approach was used to identify common unifying themes. Fourteen parents from 13 families were interviewed. The average child's age was 11 years (range 3-18) and an average 63% of their life had been spent searching for a diagnosis. Our analysis found that alignment or misalignment of parent and child needs impact the trajectory of the diagnostic search. When needs and desires align, reevaluation of a decision to pursue a diagnosis is limited. However, when there is conflict between parent and child desires, there is reevaluation, and often a pause, in the search. This tension is exacerbated when children are adolescents and attempting to balance their dependence on parents for medical care with a natural desire for independence. Our results provide novel insights into the roles of adolescents in the diagnostic odyssey. The tension between desired and realistic developmental outcomes for parents and adolescents impacts if, and how, the search for a diagnosis progresses.

A well-tolerated core needle muscle biopsy process suitable for children and adults

Serial muscle biopsies within clinical trials for Duchenne muscular dystrophy (DMD) are critical to document therapeutic responses. Less invasive means of sampling muscle are needed. We analyzed a retrospective consecutive case-series cohort of vacuum-assisted core needle muscle biopsy procedures performed on healthy and dystrophic individuals at a single institution assessing for safety and reliability of obtaining sufficient high-quality biopsy tissue for histologic assessment in adult and pediatric subjects. Of 471 muscle cores from 128 biopsy procedures, 377-550 mg of total muscle tissue was obtained per procedure with mean core weight of 129 mg (SD, 25.1 mg). All biopsies were adequate for histological assessment. There were no significant adverse events. This core needle biopsy approach, when combined with improved sample processing, provides a safe means to consistently obtain muscle samples for diagnostic and clinical trial applications.

Myopathy associated with homozygous PYROXD1 pathogenic variants detected by genome sequencing

Biallelic pathogenic variants in the gene PYROXD1 have recently been described to cause early-onset autosomal recessive myopathy. Myopathy associated with PYROXD1 pathogenic variants is rare and reported in only 17 individuals. Known pathogenic variants in PYROXD1 include missense, insertion and essential splice-site variants. Here we describe a consanguineous family of individuals affected with late-onset myopathy and homozygous PYROXD1 missense variants (NM_024854.5:c.464A>G [p.Asn155Ser]) expanding our understanding of the possible disease phenotypes of PYROXD1-associated myopathy.

De novo EIF2AK1 and EIF2AK2 Variants Are Associated with Developmental Delay, Leukoencephalopathy, and Neurologic Decompensation

EIF2AK1 and EIF2AK2 encode members of the eukaryotic translation initiation factor 2 alpha kinase (EIF2AK) family that inhibits protein synthesis in response to physiologic stress conditions. EIF2AK2 is also involved in innate immune response and the regulation of signal transduction, apoptosis, cell proliferation, and differentiation. Despite these findings, human disorders associated with deleterious variants in EIF2AK1 and EIF2AK2 have not been reported. Here, we describe the identification of nine unrelated individuals with heterozygous de novo missense variants in EIF2AK1 (1/9) or EIF2AK2 (8/9). Features seen in these nine individuals include white matter alterations (9/9), developmental delay (9/9), impaired language (9/9), cognitive impairment (8/9), ataxia (6/9), dysarthria in probands with verbal ability (6/9), hypotonia (7/9), hypertonia (6/9), and involuntary movements (3/9). Individuals with EIF2AK2 variants also exhibit neurological regression in the setting of febrile illness or infection. We use mammalian cell lines and proband-derived fibroblasts to further confirm the pathogenicity of variants in these genes and found reduced kinase activity. EIF2AKs phosphorylate eukaryotic translation initiation factor 2 subunit 1 (EIF2S1, also known as EIF2α), which then inhibits EIF2B activity. Deleterious variants in genes encoding EIF2B proteins cause childhood ataxia with central nervous system hypomyelination/vanishing white matter (CACH/VWM), a leukodystrophy characterized by neurologic regression in the setting of febrile illness and other stressors. Our findings indicate that EIF2AK2 missense variants cause a neurodevelopmental syndrome that may share phenotypic and pathogenic mechanisms with CACH/VWM.

Non-Cystic Fibrosis-Related Meconium Ileus: GUCY2C-Associated Disease Discovered through Rapid Neonatal Whole-Exome Sequencing

Meconium ileus is caused by cystic fibrosis; however, mutations in the GUCY2C gene also cause this disease. We report non-cystic fibrosis meconium ileus in an infant of non-Middle Eastern origin with compound heterozygous mutations in GUCY2C.

Lego bricks and the octet rule: Molecular models for biochemical pathways with plastic, interlocking toy bricks

The 8 studs on a 2 × 4 Lego brick conveniently represent the outer shell of electrons for carbon, nitrogen, and oxygen atoms. We used Lego bricks to model these atoms, which are then joined together to form molecules by following the Lewis octet rule. A variety of small biological molecules can be modeled in this way, such as most amino acids, fatty acids, glucose, and various intermediate metabolites. Model building with these familiar toys can be a helpful, hands-on exercise for learning-or re-learning-biochemical pathways. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(1):54-57, 2018.

Optical model for use in oceanic ecosystem models

Modeling the plankton ecosystem requires a code for simulating the profile of irradiance from the chlorophyll profile at each time step of the integration. We have compared two existing codes with data from the Biogeochemical Ocean Flux Study: the Hydrolight radiative transfer model is accurate but too slow to use interactively in ecological models; Morel's [J. Geophys. Res. 93, 10, 749 (1988)] empirical model is much faster but produces substantial error. We have developed a streamlined version of the Hydrolight radiative transfer model that is 20 times faster than the full Hydrolight code, while limiting errors to less than 12% within the euphotic zone. This new code is both fast and accurate and is, therefore, suitable for use interactively in oceanic ecosystem models.

Clinical and biochemical correlates of starting "daily" hemodialysis

BACKGROUND

Daily hemodialysis has been proposed to improve outcomes for patients with end-stage renal disease. There has been increasing evidence that daily hemodialysis might have potential advantages over intermittent dialysis. However, despite these potential advantages, daily hemodialysis is infrequently used in the United States, and published accounts on the technique are few.

METHODS

We describe patient outcomes after increasing their hemodialysis frequency from three to six times per week in a cohort of 72 patients treated at nine centers during 1972 to 1996. Analyses of predialysis blood pressure and laboratory parameters from 6 months before until 12 months after starting frequent hemodialysis used a repeated-measures statistical technique.

RESULTS

Predialysis systolic and diastolic blood pressures fell by 7 and 4 mm Hg, respectively, after starting frequent hemodialysis (P = 0.02). Reductions were greatest among patients being treated with antihypertensive medications, despite a reduction in their dosage of medications. Postdialysis weight fell by 1.0% within one month of starting frequent hemodialysis and improved control of hypertension. After the initial drop, postdialysis weight increased at a rate of 0.85 kg per six months. Serum albumin rose by 0.29 g/dl (P < 0.001) between months 1 to 12 of treatment with daily hemodialysis. Hematocrit rose by 3.0 percentage points (P = 0.02) among patients (N = 56) not treated with erythropoietin during this period. Two years after the start of daily hemodialysis, Kaplan-Meier analyses showed a patient survival of 93%, a technique survival of 77%, and an arteriovenous fistula patency of 92%. Vascular access patency was excellent despite more frequent use of the access.

CONCLUSIONS

These results suggest that in certain patients, daily hemodialysis might have advantages over three times per week hemodialysis.

Prospects for a bioartificial kidney

The developing technologies of cell therapy and tissue engineering may, in the next two decades, provide alternatives to current methods of renal replacement therapy. First, suitable organs for xenotransplantation from animals to humans may be developed, or second, as described in this report, application of tissue engineering may result in development of a range of devices to aid care of patients with renal failure. The simplest and easiest achievable devices could replace a specific aspect of renal function, such as an implantable device to produce erythropoietin. Both a bioartificial hemofilter and a renal tubule device may be developed. Ultimately this work may result in an implantable bioartificial kidney.

Vascular access survival among incident hemodialysis patients in the United States

Vascular access failure causes substantial morbidity to hemodialysis patients. We sought to identify factors determining survival of the permanent vascular access in use at the start of end-stage renal disease during 1990 in a national sample of 784 incident hemodialysis patients insured by Medicare. Medicare claims records were used to identify access failures or revisions among patients with an arteriovenous (AV) fistula (n = 245) and an AV vascular graft (n = 539). A proportional hazards analysis of time to first failure or revision, controlled by stratification for sex, race, and cause of end-stage renal disease, was used to determine the effect of age, access type, and peripheral vascular disease on vascular access survival. Patients with an AV fistula and who were older than 65 years had a risk of access failure that was 24% lower than similar patients with an AV graft (P < 0.02). The relative risk of access failure for an AV fistula, but not an AV graft, varied significantly with age for patients younger than 65 years (P < 0.01). The relative risk of access failure for a patient with an AV fistula, compared with a patient of the same age with an AV graft, was 67% lower at the age of 40 years, 54% lower at the age of 50 years, and 24% lower at the age of 65 years. A history of peripheral vascular disease was associated with a 24% higher risk of AV graft or fistula failure (P = 0.05). Measures to decrease vascular access-related morbidity among hemodialysis patients should include reversing the current trend toward increasing use of AV grafts, particularly in patients younger than 65 years.

Predictors of type of vascular access in hemodialysis patients

OBJECTIVE

Complications from vascular access account for 15% of hospital admissions among US hemodialysis patients. Complications are less frequent with arteriovenous fistulas than with synthetic grafts. We assessed clinical and nonclinical predictors of whether patients with end-stage renal disease (ESRD) starting hemodialysis receive a fistula or graft. We also investigated changes in practice between 1986-1987 and 1990.

DESIGN

Cross-sectional study.

SETTING

United States hemodialysis population.

PATIENTS

Random, national samples of ESRD patients who started hemodialysis in 1986-1987 (n=2741) or 1990 (n=1409) from United States Renal Data System Special Studies.

MAIN OUTCOME MEASURE

Type of permanent vascular access (arteriovenous fistula vs synthetic graft), analyzed using multivariate logistic regression.

RESULTS

Clinical and demographic factors as well as socioeconomic status, region of residence, and year starting hemodialysis predicted the type of vascular access. Overall, 56% of patients had grafts 30 days after starting dialysis, but graft use increased from 51% in 1986-1987 to 65% in 1990 (adjusted odds ratio [AOR], 1.67 for 1990 vs 1986-1987; 95% confidence interval [CI], 1.43-1.95; P<.001). Graft use (relative to fistula) varied by region of residence (ranging from AOR, 0.20; 95% CI, 0.14-0.28; P<.001 [New England], to AOR, 2.69; 95% CI, 2.03-3.58; P<.001 [East South Central]; both relative to the national average).

CONCLUSIONS

This national study documents large variations in the relative use of fistulas and grafts and a trend away from fistulas. The prevalence of comorbid conditions fails to explain these findings. Presentation and referral of patients early in the process of their ESRD, teaching surgeons to place fistulas, and training dialysis nurses to access fistulas may increase their use.

Comparison of mortality with home hemodialysis and center hemodialysis: a national study

We sought to determine whether lower mortality rates reported with hemodialysis (HD) at home compared to hemodialysis in dialysis centers (center HD) could be explained by patient selection. Data are from the United States Renal Data System (USRDS) Special Study Of Case Mix Severity, a random national sample of 4,892 patients who started renal replacement therapy in 1986 to 1987. Intent-to-treat analyses compared mortality between home HD (N = 70) and center HD patients (N = 3,102) using the Cox proportional hazards model. Home HD patients were younger and had a lower frequency of comorbid conditions. The unadjusted relative risk (RR) of death for home HD patients compared to center HD was 0.37 (P < 0.001). The RR adjusted for age, sex, race and diabetes, was 44% lower in home HD patients (RR = 0.56, P = 0.02). When additionally adjusted for comorbid conditions, this RR increased marginally (RR = 0.58, P = 0.03). A different analysis using national USRDS data from 1986/7 and without comorbid adjustment showed patients with training for self care hemodialysis at home or in a center (N = 418) had a lower mortality risk (RR = 0.78, P = 0.001) than center HD patients (N = 43,122). Statistical adjustment for comorbid conditions in addition to age, sex, race, and diabetes explains only a small amount of the lower mortality with home HD.

Prostacyclin biosynthesis in essential hypertension before and during treatment

Protacyclin biosynthesis was investigated in 133 untreated newly diagnosed patients with uncomplicated essential hypertension. Urinary excretion of 6-oxo-prostaglandin F1 alpha and of 2,3-dinor-6-oxo-prostaglandin F1 alpha, stable breakdown products of prostacyclin, was measured following a 1 month run-in period. To determine whether lowering blood pressure (BP) influenced prostacyclin biosynthesis, 106 consenting patients with diastolic pressure 90-120 mm Hg were allocated randomly to treatment with bendrofluazide, metoprolol, quinapril or amlodipine in an open parallel group design. Dose was increased to reduce diastolic arterial pressure to <90 mm Hg. Terazosin was added if this target BP was not achieved, and its dose increased if necessary. Urinary excretion rates of prostaglandins were measured after 1 year in patients in whom the target diastolic pressure was achieved. Mean arterial pressure varied from 106-168 mm Hg in untreated patients and excretion of both prostacyclin-derived products varied from <5 to >350 ng/g creatinine. Arterial pressure and prostaglandin excretion were not significantly correlated. In 57 patients in whom target pressure was achieved, BP before treatment was 166 +/- 2/100 +/- 1 at baseline and 144 +/- 2/86 +/- 1 mm Hg at 1 year. Excretion rates of each prostacyclin-derived product were similar before treatment and at 1 year, with no significant differences between the drugs. These findings do not support the hypothesis that deficient prostacyclin biosynthesis contributes to the pathogenesis of essential hypertension, or that increased prostacyclin biosynthesis plays a part in the response to treatment with antihypertensive medication.

Inhibition by nitroprusside of platelet calcium mobilization: evidence for reduced sensitivity to nitric oxide in essential hypertension

OBJECTIVE

Although platelets from patients with moderate hypertension are abnormally sensitive to agonist-induced aggregation, their sensitivity to antagonists is not known. Nitric oxide (NO) is an endogenous antagonist of platelet function. The objective of this study was to determine whether platelet sensitivity to the inhibitory activity of sodium nitroprusside, a donor of NO, is abnormal in hypertension.

DESIGN AND METHODS

Untreated patients with uncomplicated essential hypertension (mean arterial pressure > 120 mmHg) were studied. The rise in cytosolic calcium in response to 9,11-deoxy-11 alpha, 9 alpha-epoxymethanoprostaglandin F2 alpha (U46619, a thromboxane mimetic) was measured in fura-2-loaded platelets from 20 patients and 15 normotensive healthy subjects. Inhibition by sodium nitroprusside was measured in a further group of 14 patients and 20 normotensive subjects.

RESULTS

Basal cytosolic calcium concentration and the rise in this parameter induced by U46619 were significantly greater in platelets from hypertensive patients than in those from normotensive controls. The mean half-maximal inhibitory concentration of nitroprusside to calcium mobilization induced by 3 mumol/l U46619 was 3.1-fold greater in platelets from hypertensive patients than in those from controls (95% confidence interval 1.6-6.0).

CONCLUSION

The sensitivity of platelets to nitroprusside is reduced in essential hypertension. This reduced sensitivity to NO might influence the risk of arterial thrombosis in hypertensives.

Is this the right time to come out? Case study

In this fictional case study, Adam Lawson is a promising young associate at Kirkham McDowell Securities, a St. Louis underwriting and financial advisory firm. Recently, Adam helped to bring in an extremely lucrative deal, and soon he and a few other associates will be honored for their efforts at the firm's silver anniversary dinner. George Campbell, vice president in mergers and acquisitions, is caught unprepared when Adam tells him that, after serious reflection, he has decided to bring his partner, Robert Collins, to the banquet. George is one of Adam's biggest supporters at the firm, and he personally has no problem with Adam being gay. But it is one thing for Adam to come out of the closet at the office. It is quite another to do so at a public company-client event. After all, Kirkham McDowell's client roster includes some very conservative companies--one of the country's largest defense contractors, for example. George is concerned with how Adam's openness about his sexual orientation will play with their clients and, as a result, how senior management will react. Adam has not come to George for permission to bring Robert to the dinner. But clearly Adam wants some sort of response. George has never faced sexual diversity issues in the workplace before, and there is no company policy to guide him. Just how negative an effect could Robert have on Adam's career with the firm and the firm's relationship with its clients? Isn't it possible that even the firm's most conservative clients will simply decide that Adam's choice of guest is a personal matter--not a business one?(ABSTRACT TRUNCATED AT 250 WORDS)

Disopyramide kinetics in patients with acute myocardial infarction

The kinetic behavior of disopyramide was studied in 20 patients with suspected myocardial infarction: in 13 of these, the diagnosis was subsequently confirmed. All received a 400-mg oral loading dose of disopyramide base followed by an oral maintenance regimen of either 100 or 200 mg 4 times daily. The elimination half-life (t1/2beta) was longer (p less than 0.05) in patients with confirmed infarction than in patients with unconfirmed infarction [38.0 +/- 3.7 hr (mean +/- SEM) compared to 24.3 +/- 0.8 hr, and 21.2 +/- 2.1 hr compared to 7.2 +/- 2.4 hr for the 100- and 200-mg maintenance dose regimens, respectively]. The t1/2beta was dose dependent for infarct and noninfarct patients. Two of the patients with confirmed infarction failed to reach trough plasma levels equal to or exceeding the lower end of the manufacturer's recommended therapeutic range (3.3 mug/ml) during the study. For the remaining 11 patients the time taken to achieve trough plasma levels of 3.3 mug/ml varied from 18 to 170 hr; hence plasma disopyramide concentration in these patients was suboptimal at a time when the risk of arrhythmias is high. Modification of existing oral loading dose regimens is therefore required for optimization of oral disopyramide therapy.

Acute transmural myocardial infarction associated with active Coxsackie virus B infection

Out of a total of 233 patients suffering from transmural myocardial infarction, 20 patients were found to have serologic evidence of a concurrent active Coxsackie virus B infection. While the infection may have been coincidental, it is also possible that the virus may have played some part in the illness. Conceivably, myocarditis could be mistaken for infarction or, by some mechanism as yet unknown, the virus might precipitate infarction in susceptible subjects.