Automated Algorithm for GI Spike Burst Detection and Demonstration of Efficacy in Ischemic Small Intestine

We present a novel, fully-automated gastrointestinal spike burst detection algorithm. Following pre-processing with SALPA (Wagenaar and Potter, J. Neurosci. Methods 120:113–120, 2002) and a Savitzky–Golay filter to remove unwanted low and high frequency components, candidate spike waveforms are detected utilizing the non-linear energy operator. Candidate waveforms are classified as spikes or artifact by a support vector machine. The new method achieves highly satisfactory performance with >90% sensitivity and positive prediction value. We also demonstrate an application of the new method to detect changes in spike rate and spatial propagation patterns upon induction of mesenteric ischemia in the small intestine. Spike rates were observed to transiently increase 10–20 fold for a duration of ≈600 s, relative to baseline conditions. In ischemic conditions, spike activity propagation patterns included retrograde-longitudinal wavefronts with occasional spontaneous conduction blocks, as well as self-terminating concentric-circumferential wavefronts. Longitudinal and circumferential velocities were 6.8–8.0 cm/s and 18.7 cm/s, respectively.     

Perinatal depression screening practices in a large health system: identifying current state and assessing opportunities to provide more equitable care

The purpose of this study was to assess the prevalence of prenatal and postpartum depression screening in a large health system and to identify covariates for screening, with a specific focus in understanding disparities in practice. A retrospective cohort of women with deliveries in 2016 was created using electronic health records. Primary outcomes were depression screening during pregnancy and the first 3 months postpartum. Generalized linear mixed models with women nested within clinic were used to determine the effect of maternal and clinical characteristics on depression screening. The sample included 7548 women who received prenatal care at 35 clinics and delivered at 10 hospitals. The postpartum sample included 7059 women who returned within 3 months for a postpartum visit. Of those, 65.1% were screened for depression during pregnancy, and 64.4% were screened postpartum. Clinic site was the strongest predictor of screening, accounting for 23–30% of the variability in screening prevalence. There were no disparities identified with regard to prenatal screening. However, several disparities were identified for postpartum screening. After adjusting for clinic, women who were African American, Asian, and otherwise non-white (Native American, multi-racial) were less likely to be screened postpartum than white women (AOR (CI)’s 0.81 (0.65, 1.01), 0.64 (0.53, 0.77), and 0.44 (0.21, 0.96), respectively). Women insured by Medicaid/Medicare, a proxy for low-income, were less likely to be screened postpartum than women who were privately insured (AOR (CI) 0.78 (0.68, 0.89)). National guidelines support universal depression screening of pregnant and postpartum women. The current study found opportunities for improvement in order to achieve universal screening and to deliver equitable care.

     

Long Term Effect of Intensive Lifestyle Intervention on Cerebral Blood Flow

Objectives

To determine whether long‐term behavioral intervention targeting weight loss through increased physical activity and reduced caloric intake would alter cerebral blood flow (CBF ) in individuals with type 2 diabetes mellitus.

Design

Postrandomization assessment of CBF.

Setting

Action for Health in Diabetes multicenter randomized controlled clinical trial.

Participants

Individuals with type 2 diabetes mellitus who were overweight or obese and aged 45 to 76 (N = 310).

Interventions

A multidomain intensive lifestyle intervention (ILI ) to induce weight loss and increase physical activity for 8 to 11 years or diabetes support and education (DSE ), a control condition.

Measurements

Participants underwent cognitive assessment and standardized brain magnetic resonance imaging (MRI ) (3.0 Tesla) to assess CBF an average of 10.4 years after randomization.

Results

Weight changes from baseline to time of MRI averaged ?6.2% for ILI and ?2.8% for DSE (P < .001), and increases in self‐reported moderate or intense physical activity averaged 444.3 kcal/wk for ILI and 114.8 kcal/wk for DSE (P = .03). Overall mean CBF was 6% greater for ILI than DSE (P = .04), with the largest mean differences between ILI and DSE in the limbic region (3.39 mL /100 g per minute, 95% confidence interval (CI ) = 0.07–6.70 mL /100 g per minute) and occipital lobes (3.52 mL /100 g per minute, 95% CI = 0.20–6.84 mL /100 g per minute). In ILI , greater CBF was associated with greater decreases in weight and greater increases in physical activity. The relationship between CBF and scores on a composite measure of cognitive function varied between intervention groups (P = .02).

Conclusions

Long‐term weight loss intervention in overweight and obese adults with type 2 diabetes mellitus is associated with greater CBF .

     

The primary plasminogen-activator inhibitors in endothelial cells, platelets, serum, and plasma are immunologically related.

Monospecific antiserum to an unusually stable Mr 50,000 plasminogen-activator inhibitor (PAI) purified from cultured bovine aortic endothelial cells was employed in conjunction with reverse fibrin autography to determine whether human platelets, serum, and plasma contain immunologically related inhibitors. Reverse fibrin autography revealed the presence of a Mr 50,000 inhibitor in the platelet and serum samples but not in normal plasma. However, a Mr 50,000 inhibitor was detected in plasma obtained from individuals with increased PAI activity. In each case, treatment of the sample with the anti-inhibitor serum removed the Mr 50,000 inhibitor. The inhibitor present in each sample neutralized exogenously added tissue-type plasminogen activator in a rapid manner. Inhibition was associated with the formation of a NaDodSO4-resistant enzyme-inhibitor complex of Mr 120,000. Again, treatment of the samples with the anti-inhibitor serum removed both the inhibitory activity and the component in these samples that binds to tissue-type plasminogen activator. Thus, the rapidly acting PAI present in human platelets, serum, and patient plasma is immunologically related to the PAI synthesized by cultured bovine aortic endothelial cells. This molecule may be the physiologically relevant inhibitor of plasminogen activator in the vascular system and, as such, may serve an important role in regulating the initiation of vascular fibrinolysis.     

Histopathology of the conduction system in the sudden infant death syndrome.

The cause of the sudden infant death syndrome (SIDS, crib death, or cot death) is unknown. Current hypotheses include lability of heart rate and/or rhythm as a pathogenetic factor. The conduction system of 50 infants coming to autopsy were examined by serial sections; the infants were from newborn to two years of age. Twenty-six were SIDS deaths and 24 were explained deaths (ED). The frequency of histologic abnormalities of the specialized tissue was almost identical in both groups of infants. Hemorrhage in or around different parts of the conduction system was present in 27% SIDS and 29% ED. There was no evidence of cell death or degeneration of conduction fibers, nor obstructive lesions of the atrioventricular (A-V) arteries. Apparent moulding of A-V node and His bundle was a universal finding in both SIDS and ED, and consisted of irregular interdigitation of A-V node and His bundle fibers with the myxoid central fibrous body (CFB). Isolated bundles of conduction fibers residing in CFB and membranous ventricular septum were seen in two SIDS, but no direct contact between these fibers and the working myocardium could be identified in serial sections in either case. Without corroborating antemortem electrophysiologic data, the functional significance of morphologic findings in the conduction system of SIDS must remain conjectural.     

Provider Visits and Early Vascular Access Placement in Maintenance Hemodialysis

Medicare reimbursement policy encourages frequent provider visits for patients with ESRD undergoing hemodialysis. We hypothesize that patients seen more frequently by their nephrologist or advanced practitioner within the first 90 days of hemodialysis are more likely to undergo surgery to create an arteriovenous (AV) fistula or place an AV graft. We selected 35,959 patients aged ≥67 years starting hemodialysis in the United States from a national registry. We used multivariable regression to evaluate the associations between mean visit frequency and AV fistula creation or graft placement in the first 90 days of hemodialysis. We conducted an instrumental variable analysis to test the sensitivity of our findings to potential bias from unobserved characteristics. One additional visit per month in the first 90 days of hemodialysis was associated with a 21% increase in the odds of AV fistula creation or graft placement during that period (95% confidence interval, 19% to 24%), corresponding to an average 4.5% increase in absolute probability. An instrumental variable analysis demonstrated similar findings. Excluding visits in months when patients were hospitalized, one additional visit per month was associated with a 10% increase in odds of vascular access surgery (95% confidence interval, 8% to 13%). In conclusion, patients seen more frequently by care providers in the first 90 days of hemodialysis undergo earlier AV fistula creation or graft placement. Payment policies that encourage more frequent visits to patients at key clinical time points may yield more favorable health outcomes than policies that operate irrespective of patients’ health status.