Corticosteroid outcome may be dependent of duration of use in severe COVID-19

Background/Aims

For patients hospitalized with coronavirus disease 2019 (COVID-19) who require supplemental oxygen, the evidence of the optimal duration of corticosteroid is limited. This study aims to identify whether long-term use of corticosteroids is associated with decreased mortality.

Methods

Between February 10, 2020 and October 31, 2021, we analyzed consecutive hospitalized patients with COVID-19 with severe hypoxemia. The patients were divided into short-term (≤ 14 days) and long-term (> 14 days) corticosteroid users. The primary outcome was 60-day mortality. We performed propensity score (PS) analysis to mitigate the effect of confounders and conducted Kaplan-Meier curve analysis.

Results

There were 141 (52%) short-term users and 130 (48%) long-term corticosteroid users. The median age was 68 years and the median PaO2/FiO2 at admission was 158. Of the patients, 40.6% required high-flow nasal cannula, 48.3% required mechanical ventilation, and 11.1% required extracorporeal membrane oxygenation. The overall 60-day mortality rate was 23.2%, and that of patients with hospital-acquired pneumonia (HAP) was 22.9%. The Kaplan-Meier curve for 60- day survival in the PS-matched cohort showed that corticosteroid for > 14 days was associated with decreased mortality (p = 0.0033). There were no significant differences in bacteremia and HAP between the groups. An adjusted odds ratio for the risk of 60-day mortality in short-term users was 5.53 (95% confidence interval, 1.90-18.26; p = 0.003).

Conclusions

For patients with severe COVID-19, long-term use of corticosteroids was associated with decreased mortality, with no increase in nosocomial complications. Corticosteroid use for > 14 days can benefit patients with severe COVID-19.

Real-world data on the incidence and risk of Guillain-Barré syndrome following SARS-CoV-2 vaccination: a prospective surveillance study

Increasing evidence suggests an association between SARS-CoV-2 vaccines and Guillain-Barré syndrome (GBS). Nevertheless, little is understood about the contributing risk factors and clinical characteristics of GBS post SARS-CoV-2 vaccination. In this prospective surveillance study of 38,828,691 SARS-CoV-2 vaccine doses administered from February 2021 to March 2022 in the Gyeonggi Province, South Korea, 55 cases of GBS were reported post vaccination. We estimated the incidence rate of GBS per million doses and the incidence rate ratio for the vaccine dose, mechanism, age, and sex. Additionally, we compared the clinical characteristics of GBS following mRNA-based and viral vector-based vaccinations. The overall incidence of GBS following SARS-CoV-2 vaccination was 1.42 per million doses. Viral vector-based vaccines were associated with a higher risk of GBS. Men were more likely to develop GBS than women. The third dose of vaccine was associated with a lower risk of developing GBS. Classic sensorimotor and pure motor subtypes were the predominant clinical subtypes, and demyelinating type was the predominant electrodiagnostic subtype. The initial dose of viral-vector based vaccine and later doses of mRNA-based vaccine were associated with GBS, respectively. GBS following SARS-CoV-2 vaccination may not be clinically distinct. However, physicians should pay close attention to the classic presentation of GBS in men receiving an initial dose of viral vector-based SARS-CoV-2 vaccines.

Correlations Between Psychological Status and Perception of Facial Expression

OBJECTIVE

Facial affect recognition is associated with neuropsychological status and psychiatric diseases. We hypothesized that facial affect recognition is associated with psychological status and perception of other affects.

METHODS

A total of 80 images depicting facial affect, including 20 Neutral, 20 Angry, 20 Fear, and 20 Sad, were screened for use in our research. A total of 100 healthy individuals were asked to rate these images using a 10-point Likert scale and complete psychological scales assessing the emotional statuses and cognitive functions.

RESULTS

The participants' emotional state of aggression, attention, and impulsivity may have been associated with their interpretation of the Angry facial expressions. The participants often rated the Angry facial expressions as Fear. The participants rated Fear images as Angry or Sad. In response to a Sad facial expression, the participants reported psychological statuses of attention and impulsivity which were associated with the facial expression rating. The participants rated the Sad expression as Angry or Fear.

CONCLUSION

The psychological statuses of the participants were significantly correlated with their interpretation of facial affects. In particular, a psychological state of attention was often correlated with incorrect affect ratings. Attention and impulsivity could affect the rating of the sad facial expressions.

E-cigarette-associated Severe Pneumonia in Korea Using Data Linkage between the Korea National Health and Nutrition Examination Survey (KNHANES, 2013-2019) and the National Health Insurance Service (NHIS) Claims Database

BACKGROUND

This study aimed to investigate the association between e-cigarette (EC) use and development of acute severe pneumonia in the Korean population using a national database.

METHODS

We conducted a retrospective analysis using linkage of data between the Korean National Health and Nutrition Examination Survey (KNHANES) and the National Health Insurance Service (NHIS) administrative claims database. The primary endpoint of this study was development of severe pneumonia requiring hospital admission according to EC use during the study period. The secondary endpoints were in-hospital mortality, intensive care unit (ICU) admission, ventilator care, and days of hospital stay.

RESULTS

The final analysis included 28,950 individuals, of which 578 (2.0%) were EC users. EC users were younger and more often male than non-EC users. The EC users showed higher level of education and household income and had fewer comorbidities. Severe pneumonia was noted in 37 of 28,372 non-EC users (0.13%), but there were no occurrences of severe pneumonia in EC users. The incidence of pneumonia occurrence was not different between the two groups (P = 1.000).

CONCLUSIONS

Since e-cigarette or vaping use-associated lung injury (EVALI) is most likely included in acute severe pneumonia occurring within 3 months of EC use, it is considered that there might be no EVALI patients in Korea during the investigation period. A large-scale, prospective study is necessary to evaluate the association between EC use and acute lung injury.

Appropriate number of observations for determining hand hygiene compliance among healthcare workers

We sought to determine the minimum number of observations needed to determine hand hygiene (HH) compliance among healthcare workers. The study was conducted at a referral hospital in South Korea. We retrospectively analyzed the result of HH monitoring from January to December 2018. HH compliance was calculated by dividing the number of observed HH actions by the total number of opportunities. Optimal HH compliance rates were calculated based on adherence to the six-step technique recommended by the World Health Organization. The minimum number of required observations (n) was calculated by the following equation using overall mean value (ρ), absolute precision (d), and confidence interval (CI) (1 − α) [the equation: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{n}} \ge Z_{\alpha /2}^{2} \times \rho \times \left( {1 - \rho } \right)/d^{2}$$\end{document}n≥Zα/22×ρ×1-ρ/d2]. We considered ds of 5%, 10%, 20%, and 30%, with CIs of 99%, 95%, and 90%. During the study period, 8791 HH opportunities among 1168 healthcare workers were monitored. Mean HH compliance and optimal HH compliance rates were 80.3% and 59.7%, respectively. The minimum number of observations required to determine HH compliance rates ranged from 2 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d$$\end{document}d: 30%, CI: 90%) to 624 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d$$\end{document}d: 5%, CI: 99%), and that for optimal HH compliance ranged from 5 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d$$\end{document}d: 30%, CI: 90%) to 642 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d$$\end{document}d: 5%, CI: 99%). Therefore, we found that our hospital required at least five observations to determine optimal HH compliance.

Risk of fracture in antidepressant users with concurrent use of benzodiazepines: A self-controlled case-series analysis

OBJECTIVE

Despite the fracture risk associated with both antidepressant (AD) medication and benzodiazepines (BDZs), they are commonly prescribed simultaneously. However, studies elucidating the effects of concurrent use of BDZs and ADs on the risk fracture are scant. The objective of this study was to evaluate the risk of fracture associated with concurrent use of BDZs in AD users, using a self-controlled case-series analysis.

METHODS

A self-controlled case-series analysis, in which the participants act as their own control, was conducted using the Korean National Health Insurance Service-National Sample Cohort database (2002-2015). We studied AD users who were prescribed BDZs and diagnosed with a fracture. The risk periods were subdivided into consecutive periods (1-30, 31-60, and > 60 days) after receiving a BDZ. A 2-week pre-exposure period and a 2-week post-exposure period were also included. The incidence rate ratio (IRR) was estimated after adjusting for age and use of co-medications.

RESULTS

A total of 3020 patients were identified during the study period. There was an increased fracture risk in the first 30 days following BDZ use (IRR: 1.88, 95% confidence interval [CI] 1.66-2.12), in the 31-60-day period (1.73, 95% CI 1.48-2.02), and beyond the 60-day period (IRR: 1.68, 95% CI 1.47-1.91). The risks of fracture were greater in men and older patients.

CONCLUSION

The concomitant use of BDZs and ADs was related to a significant increase in fracture risk. AD users should be aware of the fracture risk with concomitant BDZ use, especially for first-time BDZ users and for elderly patients.

A correlated Bayesian rank likelihood approach to multiple ROC curves for endometriosis

In analysis of diagnostic data with multiple tests, it is often the case that these tests are correlated. Modeling the correlation explicitly not only produces valid inference results but also enables borrowing of information. Motivated by the Physician Reliability Study (PRS) that investigated the diagnostic performance of physicians in diagnosing endometriosis, we construct a correlated modeling framework to estimate ROC curves and the associated area under the curves. This correlated approach is quite appealing for the PRS data set that suffers from the problem of small sample sizes, as it enables information borrowing between physician groups and sessions. Given that the test scores appear to be non-normal even after logarithm transformation, we use the ranks of the data to conduct likelihood estimation and inference. We use the deviance information criterion to select competing models and conduct simulation studies to assess model performances. In application to the PRS data set, we found that the physicians are not significantly different in their diagnostic performance between groups; however, they are different between the sessions. This suggests that clinical information may play a more important role in physicians' diagnostic performance than their experiences. Our empirical evidence also demonstrates that when using both woman- and physician-specific random effects, the model parameter estimates are much smoother.

A Bayesian multi-dimensional couple-based latent risk model with an application to infertility

Motivated by the Longitudinal Investigation of Fertility and the Environment (LIFE) Study that investigated the association between exposure to a large number of environmental pollutants and human reproductive outcomes, we propose a joint latent risk class modeling framework with an interaction between female and male partners of a couple. This formulation introduces a dependence structure between the chemical patterns within a couple and between the chemical patterns and the risk of infertility. The specification of an interaction enables the interplay between the female and male's chemical patterns on the risk of infertility in a parsimonious way. We took a Bayesian perspective to inference and used Markov chain Monte Carlo algorithms to obtain posterior estimates of model parameters. We conducted simulations to examine the performance of the estimation approach. Using the LIFE Study dataset, we found that in addition to the effect of PCB exposures on females, the male partners' PCB exposures play an important role in determining risk of infertility. Further, this risk is subadditive in the sense that there is likely a ceiling effect which limits the probability of infertility when both partners of the couple are at high risk.

A Bayesian semiparametric approach to correlated ROC surfaces with stochastic order constraints

In application of diagnostic accuracy, it is possible that a priori information may exist regarding the test score distributions, either between different disease populations for a single test or between multiple correlated tests. Few have considered constrained diagnostic accuracy analysis when the true disease status is binary; almost none when the disease status is ordinal. Motivated by a study on diagnosing endometriosis, we propose an approach to estimating diagnostic accuracy measures that can incorporate different stochastic order constraints on the test scores when an ordinal true disease status is in consideration. We show that the Dirichlet process mixture provides a convenient framework to both flexibly model the test score distributions and embed the a priori ordering constraints. We also utilize the Dirichlet process mixture to model the correlation between multiple tests. In taking a Bayesian perspective to inference, we develop an efficient Markov chain Monte Carlo algorithm to sample from the posterior distribution and provide posterior estimates of the receiver operating characteristic surfaces and the associated summary measures. The proposed approach is evaluated with extensive simulation studies, and is demonstrated with an application to the endometriosis study.

Spontaneous and indicated preterm delivery risk is increased among overweight and obese women without prepregnancy chronic disease

OBJECTIVE

To investigate the independent impact of prepregnancy obesity on preterm delivery among women without chronic diseases by gestational age, preterm category and parity.

DESIGN

A retrospective cohort study.

SETTING

Data from the Consortium on Safe Labor (CSL) in the USA (2002-08).

POPULATION

Singleton deliveries at ≥23 weeks of gestation in the CSL (43 200 nulliparas and 63 129 multiparas) with a prepregnancy body mass index (BMI) ≥18.5 kg/m² and without chronic diseases.

METHODS

Association of prepregnancy BMI and the risk of preterm delivery was examined using Poisson regression with normal weight as reference.

MAIN OUTCOME MEASURES

Preterm deliveries were categorised by gestational age (extremely, very, moderate to late) and category (spontaneous, indicated, no recorded indication).

RESULTS

Relative risk of spontaneous preterm delivery was increased for extremely preterm among obese nulliparas (1.26, 95% CI: 0.94-1.70 for overweight; 1.88, 95% CI: 1.30-2.71 for obese class I; 1.99, 95% CI: 1.32-3.01 for obese class II/III) and decreased for moderate to late preterm delivery among overweight and obese multiparas (0.90, 95% CI: 0.83-0.97 for overweight; 0.87, 95% CI: 0.78-0.97 for obese class I; 0.79, 95% CI: 0.69-0.90 for obese class II/III). Indicated preterm delivery risk was increased with prepregnancy BMI in a dose-response manner for extremely preterm and moderate to late preterm among nulliparas, as it was for moderate to late preterm delivery among multiparas.

CONCLUSIONS

Prepregnancy BMI was associated with increased risk of preterm delivery even in the absence of chronic diseases, but the association was heterogeneous by preterm categories, gestational age and parity.

TWEETABLE ABSTRACT

Obese nulliparas without chronic disease had higher risk for spontaneous delivery <28 weeks of gestation.

Preterm Birth in the Context of Increasing Income Inequality

OBJECTIVE

Preterm birth is a leading cause of infant morbidity and mortality. Little is known about the contextual effect of U.S. income inequality on preterm birth, an issue of increasing concern given that the current economic divide is the largest since 1928.

METHODS

We examined changes in inequality over time in relation to preterm birth among singleton deliveries from an electronic medical record-based cohort (n = 223,512) conducted in 11 U.S. states and the District of Columbia from 2002 to 2008. Increasing income inequality was defined as a positive change in state-level Gini coefficient from the year prior to birth. Multi-level models estimated the independent effect of increasing inequality on preterm birth (>22 and <37 weeks) controlling for maternal demographics, health behaviors, insurance status, chronic medical conditions, and state-level poverty and unemployment during the year of birth.

RESULTS

The preterm birth rate was 12.3% where inequality increased and 10.9% where it did not. After adjustment, increasing inequality remained significantly associated with preterm birth (adjusted odds ratio 1.07, 95% confidence interval 1.04, 1.11). We observed no significant interaction by insurance status or race, suggesting that increasing inequality had a broad effect across the population.

CONCLUSIONS

The contextual effect of increasing income inequality on preterm birth risk merits further study.

Preterm birth and air pollution: Critical windows of exposure for women with asthma

BACKGROUND

Ambient air pollutants may increase preterm birth (PTB) risk, but critical exposure windows are uncertain. The interaction of asthma and pollutant exposure is rarely studied.

OBJECTIVE

We sought to assess the interaction of maternal asthma and air pollutant exposures in relation to PTB risk.

METHODS

Electronic medical records for 223,502 US deliveries were linked with modified Community Multiscale Air Quality model outputs. Logistic regression with generalized estimating equations estimated the odds ratio and 95% CIs for PTB on the basis of the interaction of maternal asthma and particulate matter with aerodynamic diameter of less than 2.5 microns and particulate matter with aerodynamic diameter of less than 10 microns, ozone (O3), nitrogen oxides (NOx), sulfur dioxide (SO2), and carbon monoxide (CO) per interquartile range. For each gestational week 23 to 36, exposures among women who delivered were compared with those remaining pregnant. Three-month preconception, whole pregnancy, weeks 1 to 28, and the last 6 weeks of gestation averages were also evaluated.

RESULTS

On assessing PTB by gestational week, we found that significant asthma interactions were sporadic before 30 weeks but more common during weeks 34 to 36, with higher risk among mothers with asthma for NOx, CO, and SO2 exposure and an inverse association with O3 in week 34. Odds of PTB were significantly higher among women with asthma for CO and NOx exposure preconception and early in pregnancy. In the last 6 weeks of pregnancy, PTB risk associated with particulate matter with aerodynamic diameter of less than 10 microns was higher among women with asthma.

CONCLUSIONS

Mothers with asthma may experience a higher risk for PTB after exposure to traffic-related pollutants such as CO and NOx, particularly for exposures 3-months preconception and in the early weeks of pregnancy.

An Integrated Bayesian Nonparametric Approach for Stochastic and Variability Orders in ROC Curve Estimation: An Application to Endometriosis Diagnosis

In estimating ROC curves of multiple tests, some a priori constraints may exist, either between the healthy and diseased populations within a test or between tests within a population. In this paper, we proposed an integrated modeling approach for ROC curves that jointly accounts for stochastic and variability orders. The stochastic order constrains the distributional centers of the diseased and healthy populations within a test, while the variability order constrains the distributional spreads of the tests within each of the populations. Under a Bayesian nonparametric framework, we used features of the Dirichlet process mixture to incorporate these order constraints in a natural way. We applied the proposed approach to data from the Physician Reliability Study that investigated the accuracy of diagnosing endometriosis using different clinical information. To address the issue of no gold standard in the real data, we used a sensitivity analysis approach that exploited diagnosis from a panel of experts. To demonstrate the performance of the methodology, we conducted simulation studies with varying sample sizes, distributional assumptions and order constraints. Supplementary materials for this article are available online.

Does maternal asthma contribute to racial/ethnic disparities in obstetrical and neonatal complications?

PURPOSE

To examine whether maternal asthma contributes to racial/ethnic differences in obstetrical and neonatal complications.

METHODS

Data on white (n = 110,603), black (n = 50,284), and Hispanic (n = 38,831) singleton deliveries came from the Consortium on Safe Labor. Multilevel logistic regression models, with an interaction term for asthma and race/ethnicity, estimated within-group adjusted odds ratios (aORs) for gestational diabetes, gestational hypertension, pre-eclampsia, placental abruption, premature rupture of membranes, preterm delivery, maternal hemorrhage, neonatal intensive care unit admissions, small for gestational age, apnea, respiratory distress syndrome, transient tachypnea of the newborn, anemia, and hyperbilirubinemia after adjustment for clinical and demographic confounders. Nonasthmatics of the same racial/ethnic group were the reference group.

RESULTS

Compared with nonasthmatics, white asthmatics had increased odds of pre-eclampsia (aOR, 1.28; 95% confidence interval [CI], 1.15-1.43) and maternal hemorrhage (aOR, 1.14; 95% CI, 1.04-1.23). White and Hispanic infants were more likely to have neonatal intensive care unit admissions (aOR, 1.19; 95% CI, 1.11-1.28; aOR, 1.16; 95% CI, 1.02-1.32, respectively) and be small for gestational age (aOR, 1.11; 95% CI, 1.02-1.20; aOR, 1.26; 95% CI, 1.10-1.44, respectively), and Hispanic infants were more likely to have apnea (aOR, 1.32; 95% CI, 1.02-1.69).

CONCLUSIONS

Maternal asthma did not affect most obstetrical and neonatal complication risks within racial/ethnic groups. Despite their increased risk for both asthma and many complications, our findings for black women were null. Asthma did not contribute to racial/ethnic disparities in complications.

Semiparametric Bayesian joint modeling of a binary and continuous outcome with applications in toxicological risk assessment

Many dose-response studies collect data on correlated outcomes. For example, in developmental toxicity studies, uterine weight and presence of malformed pups are measured on the same dam. Joint modeling can result in more efficient inferences than independent models for each outcome. Most methods for joint modeling assume standard parametric response distributions. However, in toxicity studies, it is possible that response distributions vary in location and shape with dose, which may not be easily captured by standard models. To address this issue, we propose a semiparametric Bayesian joint model for a binary and continuous response. In our model, a kernel stick-breaking process prior is assigned to the distribution of a random effect shared across outcomes, which allows flexible changes in distribution shape with dose shared across outcomes. The model also includes outcome-specific fixed effects to allow different location effects. In simulation studies, we found that the proposed model provides accurate estimates of toxicological risk when the data do not satisfy assumptions of standard parametric models. We apply our method to data from a developmental toxicity study of ethylene glycol diethyl ether.

Omega-3 supplementation lowers inflammation in healthy middle-aged and older adults: a randomized controlled trial

Observational studies have linked lower levels of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) with inflammation and depression. This study was designed to determine whether n-3 supplementation would decrease serum cytokine production and depressive symptoms in 138 healthy middle-aged and older adults (average age=51.04, SD=7.76) who were sedentary and overweight (average BMI=30.59, SD=4.50). This three-arm randomized, placebo-controlled, double-blind 4-month trial compared responses to (1) 2.5 g/d n-3 PUFAs, or (2) 1.25 g/d n-3 PUFAs, or (3) placebo capsules that mirrored the proportions of fatty acids in the typical American diet. Serum interleukin-6 decreased by 10% and 12% in our low and high dose n-3 groups, respectively, compared to a 36% increase in the placebo group. Similarly, low and high dose n-3 groups showed modest 0.2% and -2.3% changes in serum tumor necrosis factor alpha, compared to a 12% increase in the control group. Depressive symptoms were quite low at baseline and did not change significantly in response to supplementation. Our data suggest that n-3 PUFAs can reduce inflammation in overweight, sedentary middle-aged and older adults, and thus could have broad health benefits. These data provide a window into the ways in which the n-3 PUFAs may impact disease initiation, progression, and resolution. ClinicalTrials.gov identifier: NCT00385723.

Prognostic factors for recurrence after bilateral rectus recession procedure in patients with intermittent exotropia

PURPOSE

The purpose of this study is to evaluate prognostic factors, specifically age, at the time of surgery, for recurrence after bilateral lateral rectus recession (BLR) in patients with intermittent exotropia.

METHODS

Medical records of 511 subjects who underwent BLR procedures between the ages of 3 and 10 years with more than 12 months of follow-up were retrospectively reviewed. Patients' surgical outcomes with a deviation of less than 10 prism diopters (PD) exotropia and less than 5 PD esotropia were defined as a success. Outcomes with more than 11 PD exotropia were designated as recurrences, and those with esotropia of more than 5 PD after 3 months of surgery were noted as overcorrection. Prognostic factors for recurrence were analyzed by multivariate logistic regression test.

RESULTS

Of the 511 subjects, 371 had successful surgical outcomes and 129 had recurrences, whereas 11 were found to be overcorrected. Age at surgery and immediate postoperative alignment proved to be significant factors influencing a favorable outcome by multivariate logistic regression analysis (P<0.05). However, gender, photophobia, age at onset, spherical equivalent (SE) refractive error, astigmatism, SE anisometropia, and preoperative deviation size were not significantly predictive of success (P>0.05).

CONCLUSION

In BLR procedures, increasing patient age at surgery was associated with lower recurrence rates.

Adiponectin, leptin, and yoga practice

To address the mechanisms underlying hatha yoga's potential stress-reduction benefits, we compared adiponectin and leptin data from well-matched novice and expert yoga practitioners. These adipocytokines have counter-regulatory functions in inflammation; leptin plays a proinflammatory role, while adiponectin has anti-inflammatory properties. Fifty healthy women (mean age=41.32, range=30-65), 25 novices and 25 experts, provided fasting blood samples during three separate visits. Leptin was 36% higher among novices compared to experts, P=.008. Analysis of adiponectin revealed a borderline effect of yoga expertise, P=.08; experts' average adiponectin levels were 28% higher than novices across the three visits. In contrast, experts' average adiponectin to leptin ratio was nearly twice that of novices, P=.009. Frequency of self-reported yoga practice showed significant negative relationships with leptin; more weeks of yoga practice over the last year, more lifetime yoga sessions, and more years of yoga practice were all significantly associated with lower leptin, with similar findings for the adiponectin to leptin ratio. Novices and experts did not show even marginal differences on behavioral and physiological dimensions that might represent potential confounds, including BMI, central adiposity, cardiorespiratory fitness, and diet. Prospective studies addressing increased risk for type II diabetes, hypertension, and cardiovascular disease have highlighted the importance of these adipocytokines in modulating inflammation. Although these health risks are clearly related to more extreme values then we found in our healthy sample, our data raise the possibility that longer-term and/or more intensive yoga practice could have beneficial health consequences by altering leptin and adiponectin production.

Use of a near-field optical probe to locally launch surface plasmon polaritons on plasmonic waveguides: A study by the finite difference time domain method

We used the finite difference time domain (FDTD) method to study the use of scanning near field optical microscopy (SNOM) to locally excite the nanometric plasmonic waveguides. In our calculation, the light is funneled through a SNOM probe with a sub-wavelength optical aperture and is irradiated on one end of two types of plasmonic waveguides made of 50 nm Au sphere arrays and Au nanowires. The incident light was well localized at one end of the waveguides and consequently propagated toward the other end, due to the excitation of surface plasmon polaritons. We found that the propagation length of the nanosphere array type waveguide varies from 100 to 130 nm depending on the light wavelength, the size of the probe aperture, and the launching heights. Our result shows that reducing the aperture size and using the light of the plasmon resonance wavelength of the nanosphere array could increase the propagation length and, thus, the efficiency of electromagnetic energy transportation through nanosphere arrays.

Imaging in the diagnosis and follow-up evaluation of vertebral artery dissection

The purpose of this report is to discuss the value of ultrasonographic examination in the diagnosis and follow-up evaluation of vertebral artery dissection. We collected data on 8 patients with 11 pathologic vessels: 9 were affected intracranially and 6 were affected extracranially. Four vessels were affected in both intracranial and extracranial segments. Extracranial color-flow duplex sonography could detect abnormalities in every extracranial vertebral artery dissection. Most abnormal findings were non-specific, including severely reduced flow, absence of flow, and absence of diastolic flow. A specific finding (intramural hematoma) was noted in one artery. Abnormal transcranial color-coded sonographic findings included absence of flow, reduced velocity and reversed flow direction. Three intracranial dissecting arteries showed normal findings on transcranial color-coded sonography. Ultrasonographic follow-up study revealed evidence of improvement; this was noted almost exclusively in the extracranial segments of the vertebral artery but infrequently in the intracranial segment. Extracranial color-flow duplex sonography is sensitive in the detection of extracranial vertebral artery dissection, both in initial diagnosis and in follow-up evaluation.

Carotid and transcranial color-coded duplex sonography in different types of carotid-cavernous fistula

BACKGROUND AND PURPOSE

Patients with carotid-cavernous fistula (CCF) may undergo direct or indirect shunting. Ultrasonography has value that is complementary to angiography in the assessment and follow-up of these patients. The aim of this study was to characterize findings provided by carotid duplex sonography (CDS) and transcranial color-coded duplex sonography (TCCD) in patients with different types of CCF.

METHODS

CDS and TCCD were independently performed by technologists and neurologists. Digital subtraction or MR angiography was interpreted by a neuroradiologist. Ultrasonographic studies were categorized into 4 types: I, direct shunting only; II, direct shunting with a carotid aneurysm; III, indirect shunting only; and IV, mixed (direct and indirect) shunting. In addition to carotid and intracranial flow velocities, volume, and pulsatility, other direct and indirect ultrasound signs of shunting were evaluated. The direct sign of CCF was a mosaic flash detected by TCCD. Alteration of hemodynamic parameters on CDS and demonstration of draining veins with the use of TCCD were considered indirect signs.

RESULTS

Fifteen patients (8 men, 7 women) were included in the study. According to angiographic results, patients in ultrasonographic classification types I (n=7) and II (n=3) corresponded to type A of Barrow's classification. Patients with type III (n=8) were Barrow's type C. Type IV (n=1) had a combination of Barrow's types A and C. On ultrasound, both direct and indirect signs were seen in types I, II, and IV CCF. The presence of a 2-colored oval mass divided by a zone of separation without turbulence differentiated type I from type II CCF. All patients with type III CCF had indirect signs, and only 1 patient had direct signs on TCCD. Abnormal TCCD findings were most commonly seen through the transorbital window (100%), followed by the transtemporal window (63%) and transforaminal window (40%).

CONCLUSIONS

If only indirect ultrasonographic signs of CCF are present, TCCD can be used to predict an indirect CCF type on the basis of the origin of the fistula. With direct communication between carotid artery and cavernous sinus, both direct and indirect ultrasonographic signs can be found. The combination of CDS/TCCD may provide a noninvasive and reliable way to classify patients with CCF.

Ultrasonographic study and long-term follow-up of Takayasu's arteritis

BACKGROUND AND PURPOSE

Takayasu's arteritis is an inflammatory vasculopathy involving the aorta and its major branches. Little information is available on the natural history and temporal profile of changes in the carotid vessels, the major vessels involved in Takayasu's arteritis. Duplex ultrasonography may provide a reliable and efficient tool for the characterization and follow-up of the brachiocephalic vascular changes in Takayasu's arteritis.

METHODS

Sixteen female patients fulfilling the clinical diagnostic criteria for Takayasu's arteritis were studied. Mean age at onset was 23.6 years (SD = 6.0), and mean duration of follow-up was 17.1 years (SD = 11.9). The clinical features were analyzed. Only one patient had had a stroke. They had undergone at least one duplex scanning examination to evaluate the brachiocephalic vessels, including the extracranial carotid, vertebral, and subclavian arteries. Six patients underwent sequential duplex examination and long-term clinical follow-up.

RESULTS

All the studied patients had subclavian artery involvement, and 11 (69%) had common carotid artery involvement. The percentage of bilateral concomitant involvement was 100% in the common carotid artery and 33% in the subclavian artery. Homogeneous circumferential intima-media thickening was commonly seen in stenotic common carotid arteries (89%). Four patients had internal carotid artery involvement (all on the left side). In the serial duplex follow-up study, 2 of 6 patients had progressive vascular stenosis with concentric thickening, rather than longitudinal spreading, in the bilateral common carotid arteries. Left-side lesions were more prominent. Most were clinically stationary, despite severe stenosis or occlusion of the common carotid arteries.

CONCLUSIONS

The characteristic vascular lesions and progression changes in Takayasu's arteritis detected by duplex ultrasonography are quite different from those seen in ordinary atherosclerosis. Homogeneous circumferential intima-media thickening of the common carotid arteries is a highly specific ultrasonographic finding in patients with Takayasu's arteritis, particularly young women. Sequential duplex scanning showed vascular progression to be unpredictable and unrelated to medication in our patients. Further clinical investigations of vascular progression are warranted, and duplex scanning may provide a simple, safe, and accurate long-term means of follow-up.

Reverse jugular flow in a case of thrombosis of the brachiocephalic vein with an artificial arteriovenous fistula

Thrombosis of the thoracic inlet veins following placement of a central venous catheter is a well-known complication, and several findings have been reported by color Doppler sonography. However, reverse jugular flow resulting from this complication is rarely mentioned and should be differentiated from another complication of iatrogenic arteriovenous fistula between neck vessels. The authors here describe a uremic patient with an artificial arteriovenous fistula in the forearm complicated with thrombosis of the ipsilateral brachiocephalic vein. Factors permitting the differential diagnosis by coloer Doppler sonography and clinical conditions are proposed.

Diagnosis and follow-up of carotid-cavernous fistulas by carotid duplex sonography and transcranial color Doppler imaging

To investigate the suitability of extracranial carotid duplex (ECD) and transcranial color Doppler imaging (TCDI) in the diagnosis and follow-up of treatment in patients with carotid-cavernous fistulas (CCF), combined ECD and TCDI examinations were studied in seven patients with traumatic CCF. According to angiography, four patients had direct CCF, two indirect CCF and one both direct and indirect CCF. In ECD, hemodynamic parameters of the feeding artery showed an abnormally increased flow volume and decreased resistivity indices in five direct CCFs from the internal carotid artery and one indirect CCF from the external carotid artery. Direct visualization of the CCF was achieved in patients with direct CCF only, and revealed itself as a heterogeneous mosaic flash resulting from high flow velocities and turbulence. Patterns of venous drainage were detected via the transorbital and transforaminal windows in seven and five patients (four direct and one indirect CCF patients), respectively. These abnormal findings were improved or even normalized after successful treatment. In conclusion, combined ECD and TCDI examinations appear to be useful for the diagnosis and follow-up of CCF.

Extracranial carotid atherosclerosis and vascular risk factors in different types of ischemic stroke in Taiwan

BACKGROUND AND PURPOSE

The clinical patterns of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese people are different from those in whites. Studies relating carotid atherosclerosis and vascular risk factors to various types of stroke in Chinese people are lacking.

METHODS

Based on clinical information, we separated 367 stroke patients living in Taiwan into four subgroups: cortical infarction (CI), subcortical infarction (SCI), vertebrobasilar artery infarction (VBAI), and cardioembolic infarction (CEI). We assessed the extent and severity of extracranial carotid artery atherosclerosis in different types of ischemic stroke using duplex ultrasonography. Vascular risk factors and carotid atherosclerosis were then correlated with each subgroup of ischemic stroke.

RESULTS

Our data revealed that 32% of the CI subgroup, 3% of the SCI subgroup, 7% of the VBAI subgroup, and 21% of the CEI subgroup possessed severe carotid stenosis (> or = 50% stenosis or occlusion). The extent of atherosclerosis of extracranial carotid arteries, measured by plaque score, was also more severe in the CI subgroup than in the other subgroups. Diabetes mellitus was more frequent in the CI subgroup. Cardiomegaly and left ventricular hypertrophy were more commonly seen in the CEI subgroup. The VBAI subgroup was younger than the other subgroups. There were no differences in hypertension, prior stroke, alcohol intake, or serum levels of glucose, uric acid, hematocrit, lipids, and lipoproteins among the subgroups.

CONCLUSIONS

Of the Chinese patients living in Taiwan, the extent and severity of extracranial carotid artery atherosclerosis were more prominent in patients with CI than in patients with other types of ischemic stroke. In Chinese patients with CI, severe carotid stenosis is not uncommon; in Chinese patients with SCI, however, the frequency of carotid stenosis is quite low.

Noninvasive hemodynamic classification of carotid-cavernous sinus fistulas by duplex carotid sonography

The hemodynamic classification of the CCF has important implications for prognosis and therapy, but satisfactory criteria for such a differentiation are still lacking. We studied the application of extracranial duplex sonography in 14 cases of CCF with emphasis on the hemodynamic parameters of the RI and flow volume and made a correlation with the angiographic findings. We conclude with proposed duplex sonographic criteria for hemodynamic classification: (1) small RI with increased flow volume in the ICA: direct ICA-cavernous sinus fistulas (type A); (2) normal RI and flow volume in the ICA and ECA: dural branch of ICA-cavernous sinus fistulas (type B); (3) small RI with or without increased flow volume in the ECA: dural branch of ECA-cavernous sinus fistulas (type C) or dural branches of ICA- and ECA-cavernous sinus fistulas (type D). Application for assessment of the therapeutic effectiveness was also demonstrated.

The value of duplex and continuous wave Doppler sonography for evaluation of the extracranial vertebral arteries: a prospective comparison with angiography

BACKGROUND

The role of duplex sonography in the detection of the extracranial vertebral arteries is not well established. The purpose of this study was to determine the practical possibilities of vascular sonography for non-invasive investigation of the vertebral arteries.

METHODS

The extracranial vertebral artery was divided into the pretransverse segment, the intertransverse segment C6-C2, and the atlas loop. The first two segments were examined by duplex probe and the third segment, by continuous-wave probe. Sixty vertebral arteries were studied for detecting vessel diameter, peak systolic as well as diastolic frequency shifts, flow direction and Doppler flow characteristics. A blind angiographic comparison was also performed for the sake of confirming morphological findings and flow direction.

RESULTS

Duplex imaging could detect more than 90% of the vertebral arteries. The mean value of vessel diameter was 3.3 +/- 0.6 mm for the right vertebral artery and 3.5 +/- 0.5 mm for the left. Peak systolic as well as diastolic frequency shifts expressed in KHz was 1.4 +/- 0.4 versus 1.6 +/- 0.5 and 0.5 +/- 0.2 versus 0.5 +/- 0.2 in the right and the left vertebral arteries respectively. A 74% agreement in vessel size was obtained by both duplex scanning and angiography. A 100% accuracy was obtained for blood flow direction through means of a Doppler signal. Abnormal findings included stenosis or occlusion (four arteries), hypoplasia or aplasia (two arteries), and subclavian steal phenomenon (two arteries); Six of these eight were correctly predicted by confirmation of the angiographic findings.

CONCLUSIONS

A combination of duplex and continuous wave Doppler sonography was affirmed in this study as a relatively accurate screening technique for detection of vertebral artery abnormalities.

Subclavian steal phenomenon: a correlation between duplex sonographic and angiographic findings

Correlation of duplex sonography, angiography of the vertebral artery, and the degree of subclavian or innominate stenosis was carried out in ten patients with the subclavian steal phenomenon. Four successive stages of Doppler waveform were identified by duplex sonography. Three angiographic patterns of decreasing severity, permanent reversal, to-and-fro motion and delayed opacification, were found. Permanent reversal angiograms corresponded to complete reversal or late transient Doppler waveforms. To-and-fro motion and delayed opacification angiograms did not necessarily have a corresponding Doppler pattern. The different stages of subclavian steal phenomenon on duplex sonography correlated significantly with the degree of subclavian or innominate stenosis. Stenosis of at least 60% was found to produce abnormal vertebral artery Doppler sonography, except in one patient. Duplex sonography is considered to be a sensitive and convenient method for detecting abnormal vertebral artery haemodynamics and the subclavian steal phenomenon, but some other factors may be important in producing the Doppler waveforms.