Sampling rate requirement for accurate calculation of heart rate and its variability based on the electrocardiogram.

Objective. To develop analytical formulas which can serve as quantitative guidelines for the selection of the sampling rate for the electrocardiogram (ECG) required to calculate heart rate (HR) and heart rate variability (HRV) with a desired level of accuracy.Approach. We developed analytical formulas which relate the ECG sampling rate to conservative bounds on HR and HRV errors: (i) one relating HR and sampling rate to a HR error bound and (ii) the others relating sampling rate to HRV error bounds (in terms of root-mean-square of successive differences (RMSSD) and standard deviation of normal sinus beats (SDNN)). We validated the formulas using experimental data collected from 58 young healthy volunteers which encompass a wide HR and HRV ranges through strenuous exercise.Main results. The results strongly supported the validity of the analytical formulas as well as their tightness. The formulas can be used to (i) predict an upper bound of inaccuracy in HR and HRV for a given sampling rate in conjunction with HR and HRV as well as to (ii) determine a sampling rate to achieve a desired accuracy requirement at a given HR or HRV (or its range).Significance. HR and its variability (HRV) derived from the ECG have been widely utilized in a wide range of research in physiology and psychophysiology. However, there is no established guideline for the selection of the sampling rate for the ECG required to calculate HR and HRV with a desired level of accuracy. Hence, the analytical formulas may guide in selecting sampling rates for the ECG tailored to various applications of HR and HRV.

Prediction of knee adduction moment using innovative instrumented insole and deep learning neural networks in healthy female individuals.

BACKGROUND: The knee adduction moment, a biomechanical risk factor of knee osteoarthritis, is typically measured in a gait laboratory with expensive equipment and inverse dynamics modeling software. We aimed to develop a framework for a portable knee adduction moment estimation for healthy female individuals using deep learning neural networks and custom instrumented insole and evaluated its accuracy compared to the standard inverse dynamics approach. METHODS: Feed-forward, convolutional, and recurrent neural networks were applied to the data extracted from five piezo-resistive force sensors attached to the insole of a shoe. RESULTS: All models predicted knee adduction moment variables during walking with high correlation coefficients, r > 0.72, and low root mean squared errors (RMSE), ranging from 0.5% to 1.2%. The convolutional neural network is the most accurate predictor of average knee adduction moment (r = 0.96; RMSE = 0.5%) followed by the recurrent and feed-forward neural networks. CONCLUSION: These findings and the methods presented in the current study are expected to facilitate a cost-effective clinical analysis of knee adduction moment for healthy female individuals and to facilitate future research on prediction of other biomechanical risk factors using similar methods.

County trajectories of pyramid scheme victimization.

Community-level vulnerability to pyramid scheme fraud may be affected by place-based sources of strain and opportunity. Using national victim data from a pyramid scheme fraud case from 2000-2013, this research explores pyramid scheme adoption with group-based trajectory modeling (GBTM). GBTM is used to look for distinct trajectories of pyramid scheme join rates and to explore the effect of strain, as measured by a county's Social Vulnerability Index and unemployment rate, and opportunity or protection, as measured by a series of social capital variables, on the group trajectories. Findings suggest that county-level strain, including the county's Social Vulnerability Index and unemployment rate are related to pyramid scheme victimization, especially early adoption. We also find that social capital variables - which can, in theory, reduce strain or increase opportunity - have a nuanced relationship with fraud victimization. While our findings are drawn from a single pyramid scheme, they point to the potential to analyze case data to inform preventative and monitoring strategies appropriate to local-level characteristics.

NMUR1 in the NMU-Mediated Regulation of Bone Remodeling.

Neuromedin-U (NMU) is an evolutionarily conserved peptide that regulates varying physiologic effects including blood pressure, stress and allergic responses, metabolic and feeding behavior, pain perception, and neuroendocrine functions. Recently, several lines of investigation implicate NMU in regulating bone remodeling. For instance, global loss of NMU expression in male and female mice leads to high bone mass due to elevated bone formation rate with no alteration in bone resorption rate or observable defect in skeletal patterning. Additionally, NMU treatment regulates the activity of osteoblasts in vitro. The downstream pathway utilized by NMU to carry out these effects is unknown as NMU signals via two G-protein-coupled receptors (GPCRs), NMU receptor 1 (NMUR1), and NMU receptor 2 (NMUR2), and both are expressed in the postnatal skeleton. Here, we sought to address this open question and build a better understanding of the downstream pathway utilized by NMU. Our approach involved the knockdown of Nmur1 in MC3T3-E1 cells in vitro and a global knockout of Nmur1 in vivo. We detail specific cell signaling events (e.g., mTOR phosphorylation) that are deficient in the absence of NMUR1 expression yet trabecular bone volume in femora and tibiae of 12-week-old male Nmur1 knockout mice are unchanged, compared to controls. These results suggest that NMUR1 is required for NMU-dependent signaling in MC3T3-E1 cells, but it is not required for the NMU-mediated effects on bone remodeling in vivo. Future studies examining the role of NMUR2 are required to determine the downstream pathway utilized by NMU to regulate bone remodeling in vivo.

Thinking Outside the Lungs: A Case of Disseminated Abdominal Tuberculosis.

BACKGROUND Extrapulmonary tuberculosis (TB) occurs in up to one-fifth of all cases of TB, with abdominal TB accounting for 5% of all cases. It is an uncommon diagnosis in the Western world, where it is primarily identified in immigrant and immunocompromised populations. CASE REPORT We review a case in which a 47-year-old Nepalese woman with a history of cognitive dysfunction secondary to epilepsy presented with decreased appetite and diffuse abdominal pain. She was hypoxic and febrile on initial exam, and imaging indicated lung consolidation, right-sided pleural effusion, and thickening and nodularity of the omentum with patchy wall thickening of the colon. After failing to improve on a standard antibiotic regimen for treatment of pneumonia and colitis, the differential was broadened to include TB. Interferon-g release assay was subsequently found to be positive, and omental and peritoneal biopsies were obtained. The patient was started on an empiric course of rifampin, isoniazid, ethambutol, pyrazinamide, and pyridoxine. Laboratory testing revealed no immunochemical evidence of Mycobacterium species, however, Ziehl-Neelsen acid-fast stain was positive with rare acid-fast bacilli identified. CONCLUSIONS Peritoneal TB carries significant morbidity and mortality if undiagnosed or untreated. Diagnosis is challenging in the absence of a single test that can confirm or exclude this condition. In combination with clinical suspicion, it is crucial to explore history regarding socio-epidemiology (travel, incarceration, occupation, homelessness, sick contacts) and immunological risk (drug use, chemotherapy) in patients with constitutional symptoms.

Drug-Induced Immune Hemolytic Anemia due to Amoxicillin-Clavulanate: A Case Report and Review.

Drug-induced immune hemolytic anemia (DIIHA) is a rare cause of anemia. It is often difficult to distinguish from other causes of hemolytic anemia, thereby delaying diagnosis and treatment. Antibiotics, including penicillins and cephalosporins, are the drugs most often implicated in the development of DIIHA. Discontinuation of the offending agent is often sufficient for treatment. Here, we review the case of a 25-year-old Caucasian female who presented with jaundice and generalized weakness in the setting of outpatient treatment with amoxicillin-clavulanate due to sinus infection. Laboratory testing revealed transaminitis and hemolytic anemia. Direct antiglobulin test (DAT) revealed negative IgG and positive anti-C3. Cold agglutinin titer and Donath-Landsteiner test were negative. The patient was diagnosed with DIIHA most likely due to amoxicillin. She improved with drug cessation and a short course of glucocorticoids. Mechanism of DIIHA, workup, and management are subsequently reviewed.

The Perfect Storm: A Case of Ischemic Stroke in the Setting of Thyroid Storm.

Mortality in thyroid storm, without appropriate treatment, can rise as high as 100%. Thyroid storm coexisting with ischemic stroke is a rare presentation that further increases the risk of mortality. Early recognition and appropriate management are critical to the prevention of mortality and morbidity. Here, we review the case of a 63-year-old male presenting with new neurological deficits who was found to have thyroid storm; appropriate management of the co-existing conditions are also reviewed.

Emerging pathogens: A case of Wohlfahrtiimonas chitiniclastica and Ignatzschineria indica bacteremia.

Wohlfahrtiimonas chitiniclastica and Ignatzschineria indica are rare causes of infection in humans and have been linked to infestation with fly larvae in open wounds. Both organisms are emerging causes of disease globally and co-infection resulting in bacteremia is rare. An 82-year-old male with bilateral lower extremity infections was hospitalized due to fall with associated right lower extremity pain. On exam, a maggot infested ulcer was identified on his right lower extremity. On day three of hospitalization, blood cultures grew gram-negative and gram-variable rods, and methicillin-resistant Staphylococcus aureus. Further analysis of the gram negative and gram variable rods revealed W. chitiniclastica and I. indica respectively. Both I. indica and W. chitiniclastica were pan sensitive to all antimicrobials tested with the exception of tetracyclines to which W. chitiniclastica was fully resistant and I. indica was intermediately sensitive. The patient was treated with two weeks of IV ceftriaxone and was discharged with plans to complete a six-week course of IV daptomycin due to MRSA bacteremia. All repeat blood cultures were negative. Until recently W. chitiniclastica and I. indica infections have been documented only in farm and feral animals. Major risk factors for infection include: poor hygiene, open wounds, peripheral vascular disease, and myiasis. Due to the rarity of infection, identification of both organisms can be difficult, therefore a high index of suspicion is required.

Interleukin 1ß and Prostaglandin E2 affect expression of DNA methylating and demethylating enzymes in human gingival fibroblasts.

Periodontitis is a common chronic inflammatory condition that results in increased levels of inflammatory cytokines and inflammatory mediators. In addition to oral disease and tooth loss, it also causes low-grade systemic inflammation that contributes to development of systemic conditions including cardiovascular disease, pre-term birth, diabetes and cancer. Chronic inflammation is associated with epigenetic change, and it has been suggested that such changes can alter cell phenotypes in ways that contribute to both ongoing inflammation and development of associated pathologies. Here we show that exposure of human gingival fibroblasts to IL-1ß increases expression of maintenance methyltransferase DNMT1 but decreases expression of de novo methyltransferase DNMT3a and the demethylating enzyme TET1, while exposure to PGE2 decreases expression of all three enzymes. IL-1ß and PGE2 both affect global levels of DNA methylation and hydroxymethylation, as well as methylation of some specific CpG in inflammation-associated genes. The effects of IL-1ß are independent of its ability to induce production of PGE2, and the effects of PGE2 on DNMT3a expression are mediated by the EP4 receptor. The finding that exposure of fibroblasts to IL-1ß and PGE2 can result in altered expression of DNA methylating/demethylating enzymes and in changing patterns of DNA methylation suggests a mechanism through which inflammatory mediators might contribute to the increased risk of carcinogenesis associated with inflammation.

A Prospective Randomized Clinical Trial of a Novel, Noninvasive Perfusion Enhancement System for the Prevention of Hospital-Acquired Sacral Pressure Injuries.

PURPOSE: The purpose of this study was to determine the effectiveness of a novel, noninvasive perfusion enhancement system versus beds with integrated alternating pressure capabilities for the prevention of hospital-acquired sacral region (sacral, coccygeal, and ischium) pressure injuries in a high-risk, acute care patient population. DESIGN: A prospective randomized trial of high-risk inpatients without preexisting sacral region pressure injuries was conducted. SUBJECTS AND SETTING: The sample comprised 431 randomly enrolled adult patients in a 300-bed tertiary care community teaching hospital. METHODS: Subjects were randomly allocated to one of 2 groups: control and experimental. Both groups received "standard-of-care" pressure injury prevention measures per hospital policy, and both were placed on alternating pressure beds during their hospital stays. In addition, patients in the experimental group used a noninvasive perfusion enhancement system placed on top of their alternating pressure beds and recovery chairs throughout their hospital stay. Fischer's exact probability test was used to compare group differences, and odds ratio (OR) were calculated for comparing pressure injury rates in the experimental and control groups. RESULTS: Three hundred ninety-nine patients completed the trial; 186 patients were allocated to the experimental group and 213 patients to the control group. Eleven patients in the control group versus 2 in the experimental group developed hospital-acquired sacral region pressure injuries (51.6% vs 1.07%; P = .024). Control patients were 5.04 times more likely to develop hospital-acquired sacral region pressure injuries (OR = 0.1996; 95% CI, 0.0437-0.9125). CONCLUSIONS: Patients using a noninvasive perfusion enhancement system developed significantly fewer hospital-acquired sacral pressure injuries than those using an alternating pressure bed without the perfusion enhancement system. These findings suggest that a perfusion enhancement system enhances the success of use of pressure redistributing beds for prevention of hospital-acquired sacral pressure injuries.

Obesity and fast food in urban markets: a new approach using geo-referenced micro data.

This paper presents a new method of assessing the relationship between features of the built environment and obesity, particularly in urban areas. Our empirical application combines georeferenced data on the location of fast-food restaurants with data about personal health, behavioral, and neighborhood characteristics. We define a 'local food environment' for every individual utilizing buffers around a person's home address. Individual food landscapes are potentially endogenous because of spatial sorting of the population and food outlets, and the body mass index (BMI) values for individuals living close to each other are likely to be spatially correlated because of observed and unobserved individual and neighborhood effects. The potential biases associated with endogeneity and spatial correlation are handled using spatial econometric estimation techniques. Our application provides quantitative estimates of the effect of proximity to fast-food restaurants on obesity in an urban food market. We also present estimates of a policy simulation that focuses on reducing the density of fast-food restaurants in urban areas. In the simulations, we account for spatial heterogeneity in both the policy instruments and individual neighborhoods and find a small effect for the hypothesized relationships between individual BMI values and the density of fast-food restaurants.

Obesity and access to chain grocers.

Recent empirical work in the obesity literature has highlighted the role of the built environment and its potential influence in the increasing prevalence of obesity in adults and children. One feature of the built environment that has gained increasing attention is the role of access to chain grocers and their impact on body mass index (BMI). The assessment of the impacts of spatial access to chain grocers on BMI is complicated by two empirical regularities in the data. There is evidence that health outcomes such as BMI are clustered in space and that there is spatial dependence across individuals. In this article, we use an econometric model that takes into account the spatial dependence, and we allow the effect of access to differ for a person depending on whether he or she lives in a low-income community or peer group. We categorize this community using the characteristics of the people who immediately surround the individual rather than using census tracts. Using georeferenced survey data on adults in Marion County, Indiana, we find that the effect of improvements in chain grocer access on BMI varies depending on community characteristics.