Trends in cerebral venous thrombosis before and during the COVID-19 pandemic: Analysis of the National Inpatient Sample

OBJECTIVES

We sought to provide updated incidence and trend data for cerebral venous thrombosis (CVT) in the United States from 2016-2020, examine the impact of the COVID-19 pandemic on CVT, and identify predictors of in-hospital mortality.

MATERIALS AND METHODS

Validated ICD-10 codes were used to identify discharges with CVT in the National Inpatient Sample (NIS). Sample weights were applied to generate nationally representative estimates, and census data were used to compute incidence rates. The first wave of the COVID-19 pandemic was defined as January-May 2020. Trend analysis was completed using Joinpoint regression.

RESULTS

From 2016 to 2020, the incidence of CVT increased from 24.34 per 1,000,000 population per year (MPY) to 33.63 per MPY (Annual Percentage Change (APC) 8.6 %; p < 0.001). All-cause in-hospital mortality was 4.9 % [95 % CI 4.5-5.4]. On multivariable analysis, use of thrombectomy, increased age, atrial fibrillation, stroke diagnosis, infection, presence of prothrombotic hematologic conditions, lowest quartile of income, intracranial hemorrhage, and male sex were associated with in-hospital mortality. CVT incidence was similar comparing the first 5 months of 2020 and 2019 (31.37 vs 32.04; p = 0.322) with no difference in median NIHSS (2 [IQR 1-10] vs. 2 [1-9]; p = 0.959) or mortality (4.2 % vs. 5.6 %; p = 0.176).

CONCLUSIONS

CVT incidence increased in the US from 2016 to 2020 while mortality did not change. Increased age, prothrombotic state, stroke diagnosis, infection, atrial fibrillation, male sex, lowest quartile of income, intracranial hemorrhage, and use of thrombectomy were associated with in-hospital mortality following CVT. During the first wave of the COVID-19 pandemic, CVT volumes and mortality were similar to the prior year.

Endovascular Treatment of Acute Ischemic Stroke After Cardiac Interventions in the United States

Importance

Ischemic stroke is a serious complication of cardiac intervention, including surgery and percutaneous procedures. Endovascular thrombectomy (EVT) is an effective treatment for ischemic stroke and may be particularly important for cardiac intervention patients who often cannot receive intravenous thrombolysis.

Objective

To examine trends in EVT for ischemic stroke during hospitalization of patients with cardiac interventions vs those without in the United States.

Design, Setting, and Participants

This cohort study involved a retrospective analysis using data for 4888 US hospitals from the 2016-2020 National Inpatient Sample database. Participants included adults (age ≥18 years) with ischemic stroke (per codes from the International Statistical Classification of Diseases, Tenth Revision, Clinical Modification), who were organized into study groups of hospitalized patients with cardiac interventions vs without. Individuals were excluded from the study if they had either procedure prior to admission, EVT prior to cardiac intervention, EVT more than 3 days after admission or cardiac intervention, or endocarditis. Data were analyzed from April 2023 to October 2023.

Exposures

Cardiac intervention during admission.

Main Outcomes and Measures

The odds of undergoing EVT by cardiac intervention status were calculated using multivariable logistic regression. Adjustments were made for stroke severity in the subgroup of patients who had a National Institutes of Health Stroke Scale (NIHSS) score documented. As a secondary outcome, the odds of discharge home by EVT status after cardiac intervention were modeled.

Results

Among 634 407 hospitalizations, the mean (SD) age of the patients was 69.8 (14.1) years, 318 363 patients (50.2%) were male, and 316 044 (49.8%) were female. A total of 12 093 had a cardiac intervention. An NIHSS score was reported in 218 576 admissions, 216 035 (34.7%) without cardiac intervention and 2541 (21.0%) with cardiac intervention (P < .001). EVT was performed in 23 660 patients (3.8%) without cardiac intervention vs 194 (1.6%) of those with cardiac intervention (P < .001). After adjustment for potential confounders, EVT was less likely to be performed in stroke patients with cardiac intervention vs those without (adjusted odds ratio [aOR], 0.27; 95% CI, 0.23-0.31), which remained consistent after adjusting for NIHSS score (aOR, 0.28; 95% CI, 0.22-0.35). Among individuals with a cardiac intervention, receiving EVT was associated with a 2-fold higher chance of discharge home (aOR, 2.21; 95% CI, 1.14-4.29).

Conclusions and Relevance

In this study, patients hospitalized with ischemic stroke and cardiac intervention may be less than half as likely to receive EVT as those without cardiac intervention. Given the known benefit of EVT, there is a need to better understand the reasons for lower rates of EVT in this patient population.

Antithrombotic Treatment for Stroke Prevention in Cervical Artery Dissection: The STOP-CAD Study

Background: Small, randomized trials of cervical artery dissection (CAD) patients showed conflicting results regarding optimal stroke prevention strategies. We aimed to compare outcomes in patients with CAD treated with antiplatelets versus anticoagulation. Methods: This is a multi-center observational retrospective international study (16 countries, 63 sites) that included CAD patients without major trauma. The exposure was antithrombotic treatment type (anticoagulation vs. antiplatelets) and outcomes were subsequent ischemic stroke and major hemorrhage (intracranial or extracranial hemorrhage). We used adjusted Cox regression with Inverse Probability of Treatment Weighting (IPTW) to determine associations between anticoagulation and study outcomes within 30 and 180 days. The main analysis used an "as treated" cross-over approach and only included outcomes occurring on the above treatments. Results: The study included 3,636 patients [402 (11.1%) received exclusively anticoagulation and 2,453 (67.5%) received exclusively antiplatelets]. By day 180, there were 162 new ischemic strokes (4.4%) and 28 major hemorrhages (0.8%); 87.0% of ischemic strokes occurred by day 30. In adjusted Cox regression with IPTW, compared to antiplatelet therapy, anticoagulation was associated with a non-significantly lower risk of subsequent ischemic stroke by day 30 (adjusted HR 0.71 95% CI 0.45-1.12, p=0.145) and by day 180 (adjusted HR 0.80 95% CI 0.28-2.24, p=0.670). Anticoagulation therapy was not associated with a higher risk of major hemorrhage by day 30 (adjusted HR 1.39 95% CI 0.35-5.45, p=0.637) but was by day 180 (adjusted HR 5.56 95% CI 1.53-20.13, p=0.009). In interaction analyses, patients with occlusive dissection had significantly lower ischemic stroke risk with anticoagulation (adjusted HR 0.40 95% CI 0.18-0.88) (Pinteraction=0.009). Conclusions: Our study does not rule out a benefit of anticoagulation in reducing ischemic stroke risk, particularly in patients with occlusive dissection. If anticoagulation is chosen, it seems reasonable to switch to antiplatelet therapy before 180 days to lower the risk of major bleeding. Large prospective studies are needed to validate our findings.

Prognosis after cerebral venous thrombosis: Mortality during initial admission and at 30 days and one year after discharge in a large Canadian population-based cohort

BACKGROUND

Prognosis following cerebral venous thrombosis (CVT) is more favorable than other stroke types, but longer-term literature is limited, and trends over time are under-explored.

OBJECTIVE

Using administrative data, we examined factors associated with mortality in the inpatient setting, at 30 days and at one year following hospital discharge among a large consecutive cohort of Canadian patients with CVT.

DESIGN/METHODS

CVT patients from British Columbia (BC), Canada from 2000 to 2017 were identified using ICD diagnosis codes from the BC subset of the Canadian Institute for Health Information's Discharge Abstract Database. Logistic regression was used to investigate factors associated with inpatient mortality and survival analysis with Cox regression was used to explore factors associated with mortality at 30 days and one year.

RESULTS

Of 554 incident CVT patients identified, 508 (92 %) survived their index admission. Older age (OR 1.04, 95 % CI 1.03-1.06, p < 0.01) and the presence of seizures (OR 2.31, 95 % CI 1.08-4.94, p = 0.03) or intracranial bleeding (OR 2.28, 95 % CI 1.08-4.85, p = 0.03) were associated with increased odds of inpatient mortality. Mortality after hospital discharge was 3.0 % at 30 days and 9.4 % at one year. Older age (HR 1.05, 95 % CI 1.02-1.08, p < 0.01 at 30 days; HR 1.05, 95 % CI 1.04-1.07, p < 0.01 at 1 year) and having recent or active malignancy (HR 4.17, 95 % CI 1.51-11.52, p < 0.01 at 30 days; HR 4.60, 95 % CI 2.60-8.11, p < 0.01 at 1 year) were significantly associated with higher risks of mortality at 30 days and one year after discharge. There were decreases in inpatient mortality over the study period, but this was offset by higher mortality within 30 days after discharge in the later study epochs.

CONCLUSIONS

Among patients discharged with a diagnosis of CVT, one-year mortality was high at 9.4 %. Older age and a history of cancer were associated with higher mortality after discharge.

Rates and reasons for hospital readmission after acute ischemic stroke in a US population-based cohort

Hospital readmissions following stroke are costly and lead to worsened patient outcomes. We examined readmissions rates, diagnoses at readmission, and risk factors associated with readmission following acute ischemic stroke (AIS) in a large United States (US) administrative database. Using the 2019 Nationwide Readmissions Database, we identified adults discharged with AIS (ICD-10-CM I63*) as the principal diagnosis. Survival analysis with Weibull accelerated failure time regression was used to examine variables associated with hospital readmission. In 2019, 273,811 of 285,451 AIS patients survived their initial hospitalization. Of these, 60,831 (22.2%) were readmitted within 2019. Based on Kaplan Meyer analysis, readmission rates were 9.7% within 30 days and 30.5% at 1 year following initial discharge. The most common causes of readmissions were stroke and post stroke sequalae (25.4% of 30-day readmissions, 15.0% of readmissions between 30-364 days), followed by sepsis (10.3% of 30-day readmissions, 9.4% of readmissions between 30-364 days), and acute renal failure (3.2% of 30-day readmissions, 3.0% of readmissions between 30-364 days). After adjusting for multiple patient and hospital-level characteristics, patients at increased risk of readmission were older (71.6 vs. 69.8 years, p<0.001) and had longer initial lengths of stay (7.6 vs. 6.2 day, p<0.001). They more often had modifiable comorbidities, including vascular risk factors (hypertension, diabetes, atrial fibrillation), depression, epilepsy, and drug abuse. Social determinants associated with increased readmission included living in an urban (vs. rural) setting, living in zip-codes with the lowest median income, and having Medicare insurance. All factors were significant at p<0.001. Unplanned hospital readmissions following AIS were high, with the most common reasons for readmission being recurrent stroke and post stroke sequalae, followed by sepsis and acute renal failure. These findings suggest that efforts to reduce readmissions should focus on optimizing secondary stroke and infection prevention, particularly among older socially disadvantaged patients.

Twenty-Year Disparity Trends in United States Stroke Death Rate by Age, Race/Ethnicity, Geography, and Socioeconomic Status

BACKGROUND AND OBJECTIVES

In 2017, the Centers for Disease Control and Prevention (CDC) issued an alert that, after decades of consistent decline, the stroke death rate levelled off in 2013, particularly in younger individuals and without clear origin. The objective of this analysis was to understand whether social determinants of health have influenced trends in stroke mortality.

METHODS

We performed a longitudinal analysis of county-level ischemic and hemorrhagic stroke death rate per 100,000 adults from 1999 to 2018 using a Bayesian spatiotemporally smoothed CDC dataset stratified by age (35-64 years [younger] and 65 years or older [older]) and then by county-level social determinants of health. We reported stroke death rate by county and the percentage change in stroke death rate during 2014-2018 compared with that during 2009-2013.

RESULTS

We included data from 3,082 counties for younger individuals and 3,019 counties for older individuals. The stroke death rate began to increase for younger individuals in 2013 (p < 0.001), and the slope of the decrease in stroke death rate tapered for older individuals (p < 0.001). During the 20-year period of our study, counties with a high social deprivation index and ≥10% Black residents consistently had the highest rates of stroke death in both age groups. Comparing stroke death rate during 2014-2018 with that during 2009-2013, larger increases in younger individuals' stroke death rate were seen in counties with ≥90% (vs <90%) non-Hispanic White individuals (3.2% mean death rate change vs 1.7%, p < 0.001), rural (vs urban) populations (2.6% vs 2.0%, p = 0.019), low (vs high) proportion of medical insurance coverage (2.9% vs 1.9%, p = 0.002), and high (vs low) substance abuse and suicide mortality (2.8 vs 1.9%, p = 0.008; 3.3% vs 1.5%, p < 0.001). In contrast to the younger individuals, in older individuals, the associations with increased death rates were with more traditional social determinants of health such as the social deprivation index, urban location, unemployment rate, and proportion of Black race and Hispanic ethnicity residents.

DISCUSSION

Improvements in the stroke death rate in the United States are slowing and even reversing in younger individuals and many US counties. County-level increases in stroke death rate were associated with distinct social determinants of health for younger vs older individuals. These findings may inform targeted public health strategies.

Effect of COVID-19 on Acute Ischemic Stroke Severity and Mortality in 2020: Results From the 2020 National Inpatient Sample

BACKGROUND

There is a paucity of nationally representative data regarding the impact of COVID-19 on acute ischemic stroke (AIS) outcome.

METHODS

We created a cross-sectional cohort of nationally weighted National Inpatient Sample nonelective hospital discharges aged ≥18 years with a diagnosis of ischemic stroke from 2016 to 2020. The outcome was in-hospital mortality and exposure was COVID-19 status. To understand the effect of COVID-19 on AIS severity, we report National Institutes of Health Stroke Scale by exposure status. In a final analysis, we used a nationally weighted logistic regression and marginal effects to compare April to December 2020 to the same period in 2019 to understand how the pandemic modified the effect of race and ethnicity and median household income on in-hospital AIS mortality.

RESULTS

We observed significantly higher AIS mortality in 2020 than prior years (2020 versus 2016-19, 7.3% versus 6.3%, P<0.001) and higher National Institutes of Health Stroke Scale in those with COVID-19 than those without (mean: 9.7±9.1 versus 6.6±7.4, P<0.001), but patients with AIS without COVID in 2020 had only marginally higher mortality (2020 versus 2016-2019, 6.6% versus 6.3%, P=0.001). Comparing April to December 2020 to 2019, the adjusted risk of in-hospital AIS mortality was most notably increased in Hispanics (2020 versus 2019: 9.2% versus 5.8%, P<0.001) and the lowest quartile of income (2020 versus 2019: 8.0% versus 6.0%, P<0.001).

CONCLUSIONS

In-hospital stroke mortality increased in 2020 in the United States because of comorbid AIS and COVID-19, which had higher stroke severity. The increase in AIS mortality during April-December 2020 was significantly more pronounced in Hispanics and those in the lowest quartile of household income.

Recanalization and Outcomes After Cerebral Venous Thrombosis: A Systematic Review and Meta-Analysis

Background

Recanalization in cerebral venous thrombosis (CVT) can begin as early as 1 week after initiating therapeutic anticoagulation. The clinical significance of recanalization remains uncertain.

Objectives

We aimed to investigate the association between recanalization and functional outcomes and explored predictors of recanalization.

Methods

A systematic literature search was conducted (EMBASE, MEDLINE, Cochrane library) to identify: (1) patients with CVT aged ≥18 years treated with anticoagulation only; (2) case series, cohort, or randomized controlled trial studies; and (3) reported recanalization rates and functional outcomes using either a modified Rankin Scale (mRS) or sequelae of CVT at last follow-up. Meta-analysis was performed using pooled odds ratios (ORs) with exploration of sex and age effects using meta-regression.

Results

Twenty-three studies were eligible with 1418 individual patients in total. Timing of reimaging and clinical reassessment was variable. Absence of recanalization was associated with increased odds of an unfavorable functional outcome (mRS 2-6 versus 0-1; OR, 3.66; 95% CI, 1.73-7.74; p = 0.001), CVT recurrence (OR, 8.81; 95% CI, 1.63-47.7; p = 0.01), and chronic headache (OR, 2.78; 95% CI, 1.16-6.70; p = 0.02). On meta-regression, the relationship between recanalization and mRS differed by the proportion of female patients, where lower proportions of women were associated with higher likelihood of a worse outcome, but not by mean participant age. There was no incremental benefit of full compared with partial recanalization with respect to favorable mRS or recurrence, but odds of chronic headache were higher with partial versus full recanalization (OR, 3.80; 95% CI, 1.43-10.11; p = 0.008). Epilepsy and visual sequelae were not associated with recanalization.

Conclusions

Absence of recanalization was associated with worse functional outcomes, CVT recurrence, and headache, but outcomes were modified by sex. The degree of recanalization was significant in relation to headache outcomes, where partial compared with complete recanalization resulted in a greater likelihood of residual headache. Prospective studies with common timing of repeat clinical-neuroimaging assessments will help to better ascertain the relationship and directionality between the degree of recanalization and outcomes.

Embolic Stroke of Undetermined Source: Current Perspectives on Diagnosis, Investigations, and Management

In 2014, Hart et al. introduced the concept of "embolic stroke of undetermined source" (ESUS) to the clinical-research stroke community. The hypothesis underlying the development of the ESUS construct was that this potentially heterogenous group of stroke mechanisms were largely thromboembolic, and would thus benefit from anticoagulation over antiplatelet for secondary prevention. Since then, 2 large clinical trials have shown that, to date, there is not a clear uniform antithrombotic strategy for secondary prevention after ESUS as it was originally broadly defined. However, this work has yielded valuable information about the patient phenotypes that experience ESUS strokes, as well as hypothesis-generating substudies that have given rise to the next generation of secondary prevention trials aimed at more personalized approaches for different suspected mechanisms of embolic stroke. In parallel with the evolution of ESUS, several studies aimed at screening for atrial fibrillation in the secondary stroke prevention population have generated additional questions about the mechanistic relevance of atrial fibrillation detected after stroke, and how this should inform poststroke workup, and secondary prevention strategies. Herein, we provide a synthesis of the current understanding surrounding the patient phenotypes that experience ESUS strokes, and previous, ongoing, and anticipated clinical trials that will guide earlier and later secondary prevention strategies and poststroke cardiac investigations.

Incidence of Cerebral Venous Thrombosis: A Population-Based Study, Systematic Review, and Meta-Analysis

BACKGROUND

Studying the baseline incidence of cerebral venous thrombosis (CVT) prior to COVID-19 and the limitations of how this has been previously reported in the literature will help improve understanding of this disease and how risks may have changed in the post-COVID era.

METHODS

We examined CVT incidence using linked administrative data in British Columbia, Canada (population 5.2 million). To contextualize our findings, we also examined CVT incidence in the published literature and searched MEDLINE and EMBASE for article titles and abstracts up to Nov 2, 2021 on CVT incidence in adults. We performed abstract screening and full-text review prior to data extraction and explored associations between CVT incidence and year of study, geographic location, and study quality with meta-analyses and meta-regression. A random-effects restricted maximum likelihood model was used. Publication bias was assessed using the Egger tests and using visual inspection of the funnel plot for symmetry.

RESULTS

There were 554 unique CVT cases (mean age 50.9 years, 55.4% women) in British Columbia from 2000 to 2017; overall annual incidence was 8.7 (95%CI' 8.0-9.4) per million. Incidence increased over time in men across the entire study period, and from 2011 to 2017 in women. We identified 22 other studies on CVT incidence before 2020 (21/23 total studies included in meta-analysis). Annual incidence overall was 12.1 (95% CI' 9.9-14.3) per million with significant between-study heterogeneity (I2 98.8%, Qp-value<0.001). There were no significant associations on meta-regression between incidence and study year, study quality score, or gross national income per capita of the study country. Visual inspection of the funnel plot and a significant Egger test (z=2.8, P<0.01) suggested possible publication bias.

CONCLUSIONS

Incidence of CVT in Canadian data increased over time but remained lower than in other population-based studies. Significant heterogeneity exists in the literature, which may be subject to publication bias.

Quantifying Improved Outcomes, Cost Savings, and Hospital Volume Changes From Optimized Emergency Stroke Transport

BACKGROUND

A previously published conditional probability model optimizes prehospital emergency transport protocols for patients with suspected large-vessel occlusion by recommending the transport strategy, drip-and-ship or mothership, that results in a higher probability of an excellent outcome. In this study, we create generalized models to quantify the change in annual hospital patient volume, the expected annual increase in the number of patients with an excellent outcome, and the annual cost savings to a single-payer healthcare system resulting from these optimized transport protocols.

METHODS

We calculated the expected number of patients with suspected large-vessel occlusion transported by ambulance over a 1-year period in a region of interest, using the annual stroke incidence rate and a large-vessel occlusion screening tool. Assuming transport to the closest hospital is the baseline transport policy across the region (drip-and-ship), we determined the change in annual hospital patient volume from implementing optimized transport protocols. We also calculated the resulting annual increase in the number of patients with an excellent outcome (modified Rankin Score of 0-1 at 90 days) and associated cost savings to a single-payer healthcare system. We then performed a case study applying these generalized models to the stroke system serving the Greater Vancouver and Fraser Valley Area, BC, Canada.

RESULTS

In the Greater Vancouver and Fraser Valley Area, there was an annual increase of 36 patients with an excellent outcome, translating to an annual cost savings of CA$2 182 824 to the British Columbia healthcare system. We also studied how these results change depending on our assumptions of treatment times at the regional stroke centers.

CONCLUSIONS

Our framework quantifies the impact of optimized emergency stroke transport protocols on hospital volume, outcomes, and cost savings to a single-payer healthcare system. When applied to a specific region of interest, these models can help inform health policies concerning emergency transport of patients with suspected large-vessel occlusion.

[Role of personalized 3D printing in brain protection after decompressive craniectomy]

Objective: To explore the application value of personalized three-dimensional (3D) printed protective cap in brain protection after decompressive craniectomy (DC). Methods: Fourty-five patients who underwent DC from January 2021 to October 2021 were selected, including 26 males and 19 females, aged 5-73 (50±13) years old. The brain CT data were imported into 3D Slicer software to rebuild the protective cap through 3D printing. The cap was worn on the head of the patient, thereby preventing secondary braindamage. The follow-up results were compared with 53 patients without protective capduring the same period. Results: There were no statistically significant differences in age, skull defect location and follow-up time between the two groups (all P>0.05).Among 45 patients, 47 brain protective caps (2 cases with bilateral skull defects) were successfully designed. The time for image post-processingand 3D printing was (21.2±6.0) min and (62.4±8.3) min, respectively. There were 6 cases of low compliance, 9 cases of moderate compliance, 32 cases of high compliance, respectively. Six cases with low conformity were redesigned and printed, 2 of 9 cases with moderate conformity were redesigned and printed, and the remaining 7 cases reached high compliance after grinding and packaging. In the current study, 45 patients with brain protective caps were followed up for 3 months, and no secondary brain injury occurred. However, among 53 patients without brain protective caps during the same period, 4 patients had secondary accidental brain compression. The incidence of injury was 7.5 %, and the difference was statistically significant (P<0.001). Conclusion: Brain protective cap designed based on cranial CT and 3D printing can be used in patients with skull defects to protect the brain tissue from secondary crush damage and has certain clinical value.

Cost-Effectiveness of Cilostazol Added to Aspirin or Clopidogrel for Secondary Prevention After Noncardioembolic Stroke

Background The objective of the study was to assess the cost-effectiveness of cilostazol (a selective phosphodiesterase 3 inhibitor) added to aspirin or clopidogrel for secondary stroke prevention in patients with noncardioembolic stroke. Methods and Results A Markov model decision tree was used to examine lifetime costs and quality-adjusted life years (QALYs) of patients with noncardioembolic stroke treated with either aspirin or clopidogrel or with additional cilostazol 100 mg twice daily. Cohorts were followed until all patients died from competing risks or ischemic or hemorrhagic stroke. Probabilistic sensitivity analysis using Monte Carlo simulation was used to model 10 000 cohorts of 10 000 patients. The addition of cilostazol to aspirin or clopidogrel is strongly cost saving. In all 10 000 simulations, the cilostazol strategy resulted in lower health care costs compared with aspirin or clopidogrel alone (mean $13 488 cost savings per patient; SD, $8087) and resulted in higher QALYs (mean, 0.585 more QALYs per patient lifetime; SD, 0.290). This result remained robust across a variety of sensitivity analyses, varying cost inputs, and treatment effects. At a willingness-to-pay threshold of $50 000/QALY, average net monetary benefit from the addition of cilostazol was $42 743 per patient over their lifetime. Conclusions Based on the best available data, the addition of cilostazol to aspirin or clopidogrel for secondary prevention following noncardioembolic stroke results in significantly reduced health care costs and a gain in lifetime QALYs.

[Clinical application analysis of a method for locating scalp projection of intracranial lesions based on neuroimaging]

Objective: To explore the feasibility of a method based on neuroimaging and surface markers for locating scalp projection of intracranial lesions. Methods: The clinical data of 46 patients who were used 'double-circle method' for locating scalp projection of intracranial lesions at Department of Neurosurgery,the First Affiliated Hospital of Xiamen University from January to June 2021 were retrospective analyzed. All patients with 2 electrodes(artificial fiducials) randomly attached to scalp had been examed thin-layer brain CT. The distances from the center of each fiducial to the root of the nose and tragus were measured through the images. A compass was used to draw two arcs with the root of nose and the tragus as the center and the pre-measured distance as the radius on patient's scalp. Then two arcs' intersection on the scalp was the fiducial. The method was named 'double-circle method'. Two neurosurgeons were arranged to perform fiducial identification with double-circle method, and record the error between the result and the actual fiducial point.Independent sample t test was used for data comparison, and Kappa test was used to analysis the inter-group consistency. Results: Ninety-two fiducial points of 46 patients were collected. Time consuming of doctor A was (8.1±2.3) minutes(range:5 to 15 minutes)and doctor B was (8.9±3.5) minutes(range:4 to 17 minutes).The positioning error from the doctor A was (4.4±2.4)mm(range:0 to 12 mm) and doctor B was(4.2±2.6) mm(range:0 to 14 mm)(t=-0.575,P=0.567),the difference was not statistically significant. The Kappa value of the consistency test of error between two doctors was 0.517(P=0.001).The consistency was moderate.Eight patients used 'double-circle method' and neuronavigation for locating scalp projection of intracranial lesions at the same time. The diameter of the lesions was (3.8±0.9)cm (range: 2.6 to 5.1 cm), and the positioning error of the 'double-circle method' and navigation was (4.0±1.9) mm(range: 1 to 6 mm), and all patients were confirmed to be accurately located during surgery. Conclusion: 'Double-circle method' is a simple,convenient and accurate way in locating intracranial lesions and has certain clinical significance.

Abstract WP185: Not All Asians Are Alike: Disaggregation Of Stroke Mortality Among Asian Subgroups

Background: Stroke is the 5th leading cause of death in the US. National stroke mortality among Asian subgroups has never been reported. Our objective is to disaggregate national stroke mortality data among the largest Asian American groups by sex and characterize mortality trends across a 12-year period.

Methods: We extracted National Vital Statistics System mortality data from 2006 to 2017 for 6 Asian subgroups and non-Hispanic Whites (NHWs). Stroke mortality was classified by ICD-10, including ischemic stroke (I630-699), intracerebral hemorrhage (I610-629), and subarachnoid hemorrhage (I601-609). 2006-2017 American Community Survey population data was extracted to calculate age-standardized mortality rates (AMRs) stratified by sex and race.

Results: Participants included 2,593 Asian Indians, 7,585 Filipinos, 8,212 Chinese, 2,551 Koreans, 3,179 Vietnamese, 4,667 Japanese, and 781,966 NHWs. Mortality from hemorrhagic strokes exceeded ischemic stroke in groups except NHW (Figure 1A). From 2006-2017, deaths from ischemic stroke increased for all groups, with higher mortality in Filipino males compared to females (figure 1B). Deaths from subarachnoid hemorrhage increased only in the Vietnamese subgroup (figure 1D). A similar trend was observed for intracerebral hemorrhage in Vietnamese males (figure 1C).

Conclusion: Disaggregation of US stroke mortality revealed important variations within the 6 largest Asian subgroups, including increased ischemic stroke mortality in all subgroups and increased hemorrhagic stroke mortality among Vietnamese. Considerations for this variation include differences in risk factor prevalence (cigarette smoking, obstructive sleep apnea) and social determinants of health. Future studies must collect disaggregated Asian subgroup data to provide tailored interventions to further reduce stroke mortality.

Figures: See below

Background incidence rates of hospitalisations and emergency department visits for thromboembolic and coagulation disorders in Ontario, Canada for COVID-19 vaccine safety assessment: a population-based retrospective observational study

OBJECTIVE

The objective of this study was to estimate background rates of selected thromboembolic and coagulation disorders in Ontario, Canada.

DESIGN

Population-based retrospective observational study using linked health administrative databases. Records of hospitalisations and emergency department visits were searched to identify cases using International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada diagnostic codes.

PARTICIPANTS

All Ontario residents.

PRIMARY OUTCOME MEASURES

Incidence rates of ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, deep vein thrombosis, pulmonary embolism, idiopathic thrombocytopaenia, disseminated intravascular coagulation and cerebral venous thrombosis during five prepandemic years (2015-2019) and 2020.

RESULTS

The average annual population was 14 million with 51% female. The mean annual rates per 100 000 population during 2015-2019 were 127.1 (95% CI 126.2 to 127.9) for ischaemic stroke, 22.0 (95% CI 21.6 to 22.3) for intracerebral haemorrhage, 9.4 (95% CI 9.2 to 9.7) for subarachnoid haemorrhage, 86.8 (95% CI 86.1 to 87.5) for deep vein thrombosis, 63.7 (95% CI 63.1 to 64.3) for pulmonary embolism, 6.1 (95% CI 5.9 to 6.3) for idiopathic thrombocytopaenia, 1.6 (95% CI 1.5 to 1.7) for disseminated intravascular coagulation, and 1.5 (95% CI 1.4 to 1.6) for cerebral venous thrombosis. Rates were lower in 2020 than during the prepandemic years for ischaemic stroke, deep vein thrombosis and idiopathic thrombocytopaenia. Rates were generally consistent over time, except for pulmonary embolism, which increased from 57.1 to 68.5 per 100 000 between 2015 and 2019. Rates were higher for females than males for subarachnoid haemorrhage, pulmonary embolism and cerebral venous thrombosis, and vice versa for ischaemic stroke and intracerebral haemorrhage. Rates increased with age for most of these conditions, but idiopathic thrombocytopaenia demonstrated a bimodal distribution with incidence peaks at 0-19 years and ≥60 years.

CONCLUSIONS

Our estimated background rates help contextualise observed events of these potential adverse events of special interest and to detect potential safety signals related to COVID-19 vaccines.

Capturing Intravenous Thrombolysis for Acute Stroke at the ICD-9 to ICD-10 Transition: Case Volume Discontinuity in the United States National Inpatient Sample

Background

Transition from International Classification of Diseases (ICD) Ninth and Tenth Revisions (ICD‐9 and ICD‐10) for hospital discharge data was mandated for US hospitals on October 1, 2015. We examined the volume of patients receiving thrombolysis in ischemic stroke (IS) identified using ICD codes within this transition period in the 2015 to 2016 National Inpatient Sample, a weighted 20% sample of all inpatient US hospital discharges.

Methods and Results

During the ICD‐10 period, 2 case identification strategies were used. Codes for IS were combined with: (1) only the ICD‐10 code for thrombolytic given into a peripheral vein and (2) all new ICD‐10 codes mapped to the ICD‐9 code for all thrombolysis. On visual inspection there was an obvious discontinuity in the volume of patients with IS treated with IV thrombolysis corresponding to 3 time periods: ICD‐9 (study period 1), transition (period 2), and ICD‐10 (period 3). With Strategy 1, analysis using a linear spline with 2 knots shows that the volume of patients with IS treated with IV thrombolysis was significantly different between study periods 1 and 2 (slope difference −1880, 95% CI −2834 to −928, P=0.005), and periods 2 to 3 (slope difference 1980, 95% CI 1207–2754, P = 0.002). With Strategy 2, volumes did not change significantly between periods 1 to 2, though there was a significant difference between periods 2 and 3 (slope difference 719, 95% CI 91–1347, P=0.034).

Conclusions

The significant discontinuity in thrombolysis volumes for IS during the transition period for ICD‐9 to ICD‐10 coding suggests that more rigorous validation of US administrative data during this time period may be necessary for research, resource planning, and quality assurance.

Abstract P243: Identifying Cerebral Venous Thrombosis Through Administrative Data: Icd-10 Case Ascertainment Depends on Clinical Context

Background: Recent reported population-based rates of cerebral venous thrombosis (CVT) are higher than in older studies, though the context of these diagnoses is not well-defined. To better understand these trends, we examined the accuracy of administrative codes ( ICD-10 ) for CVT in different clinical scenarios.

Methods: Cases of CVT presenting to a tertiary center between 2008-2018 were identified in two ways: free text search through all hospital electronic radiology reports regardless of modality and body part and any ICD-10 discharge codes (see Table 1). Electronic medical records were reviewed to verify diagnoses of CVT and their clinical context (Figure 1) to calculated Positive Predictive Value (PPV) of ICD-10 codes. Additionally, sensitivities of ICD-10 codes were calculated against all CVTs identified using either searches that were verified on chart review as the gold standard.

Results: There were 289 confirmed cases: 239 new diagnoses, 204 of which were acute events. Only 75 cases (37%) were new, symptomatic CVTs not provoked by trauma or structural processes. Sensitivity and PPV for ICD-10 codes depending on clinical context is reported in Table 1.

Conclusion: The majority of CVT identified at our institution were incidentally diagnosed in context of intracranial processes such as trauma, surgery, infection, or masses; 37% were symptomatic, non-structural incident diagnoses. Our findings have implications in interpreting CVT rates identified through administrative data, as the management and prognosis of CVT may differ based on clinical context.

Cerebral Small Vessel Disease, Risk Factors, and Cognition in Tenants of Precarious Housing

BACKGROUND AND PURPOSE

We aim to describe the burden, characteristics, and cognitive associations of cerebral small vessel disease in a Canadian sample living with multimorbidity in precarious housing.

METHODS

Participants received T1, T2-fluid-attenuated inversion recovery, and susceptibility-weighted imaging 3T magnetic resonance imaging sequences and comprehensive clinical, laboratory, and cognitive assessments. Cerebral small vessel disease burden was characterized using a modified Small Vessel Disease (mSVD) score. One point each was given for moderate-severe white matter hyperintensities, ≥1 cerebral microbleeds, and ≥1 lacune. Multivariable regression explored associations between mSVD score, risk factors, and cognitive performance.

RESULTS

Median age of the 228 participants (77% male) was 44.7 years (range, 23.3-63.2). In n=188 participants with consistent good quality magnetic resonance imaging sequences, mSVD scores were 0 (n=127, 68%), 1 (n=50, 27%), and 2 (n=11, 6%). Overall, one-third had an mSVD ≥1 n=61 (32%); this proportion was unchanged when adding participants with missing sequences n=72/228 (32%). The most prevalent feature was white matter hyperintensities 53/218 (24%) then cerebral microbleed 16/191 (8%) and lacunes 16/228 (7%). Older age (odds ratio, 1.10 [95% CI, 1.05-1.15], P<0.001), higher diastolic blood pressure (odds ratio, 1.05 [95% CI, 1.01-1.09], P=0.008), and a history of injection drug use (odds ratio, 3.13 [95% CI, 1.07-9.16], P=0.037) had significant independent associations with a mSVD score of ≥1 in multivariable analysis. mSVD ≥1 was associated with lower performance on tests of verbal memory, sustained attention, and decision-making, contributing 4% to 5% of the variance in each cognitive domain.

CONCLUSIONS

The 32% prevalence of cerebral small vessel disease in this young, socially marginalized cohort was higher than expected for age and was associated with poorer cognitive performance.

[Clinical study on asthma and aspirin asthma affecting chronic rhinosinusitis]

Objective:The aim of this study is to observe the effects of asthma and aspirin asthma on chronic rhinosinusitis and to explore the corresponding clinical value. Method: Eighty-six patients with CRS and asthma who were treated in the outpatient clinic during March 2015 to January 2018 were divided into asthma group(52 cases) and aspirin asthma group(34 cases) according to asthma and aspirin asthma. The clinical symptoms of the two groups were analyzed by symptomatic VAS score, Lund-Mackay score of sinus CT, and Lund-Kennedy score by nasal endoscopy.The scores of the two groups were compared under different lung function. Enzyme-linked immunosorbent assay the levels of inflammatory markers IL-5,IL-17,IFN-γ and TNF-α in the sinus secretions of the two groups were detected.Result:There were no significant differences in age, gender, smoking history, allergy history, surgical history and course of disease between the two groups(P<0.05), suggesting that the data were comparable. The sinus CT results showed that compared with the aspirin asthma group, the asthmatic group had irregular turbinates and a large turbinate,as shown in Figure 1. There were significant differences between the two groups in VAS score,Lund-Mackay score of sinus CT and Lund-Kennedy score by nasal endoscopy.The difference was statistically significant(P<0.05). And the forehead and/or facial pain or pain in the symptomatic VAS score(P<0.05), the Lund-Mackay score of the sinus CT(P<0.05),and intranasal.The difference in the Lund-Kennedy score(P<0.05) was statistically significant.There were significant differences in the distribution of lung function levels between the two groups of patients with mild airway obstructive respiratory dysfunction and pulmonary ventilation obstructive disorder(P<0.05).The average levels of IL-5,IL-17,IFN-γ and TNF-α in the aspirin asthma group were significantly lower than those in the asthma group(P<0.05).Conclusion:Aspirin-induced CRS produces asthma symptoms more severely than traditional asthma symptoms, but the induced local inflammatory response is relatively weak, and the mechanism may be closely related to IL-5,IL-17,IFN-γ and TNF-α levels.

Prevalence and Risk Factors of Brain Infarcts and Associations With Cognitive Performance in Tenants of Marginal Housing

Background

Homeless and vulnerably housed individuals are at increased risk for multimorbidity compared with the general population. We assessed prevalence of brain infarcts on neuroimaging and associations with vascular risk factors and cognitive performance in a prospective study of residents living in marginal housing.

Methods and Results

Two hundred twenty‐eight participants underwent structured clinical interviews, targeted clinical, laboratory, and neuropsychological assessments, and magnetic resonance imaging with T₁, T₂‐fluid‐attenuated inversion recovery and susceptibility‐weighted images. Subjects underwent cognitive testing to assess premorbid IQ, verbal learning and memory, inhibition, sustained attention, mental flexibility, and decision making. In this sample (mean age 44.0 years [SD 9.4], 77% male), prevalence of conventional vascular risk factors was lower than in the general population apart from tobacco use (94%). Ten‐year Framingham risk for any cardiovascular event was 11.4%±9.2%. Brain infarcts were present in 25/228 (11%). All were ischemic (40% cortical, 56% lacunar, 4% both). Participants with infarcts were older than those without (48.9±9.4 versus 43.4±9.2, P=0.006). In a multivariable regression analysis, only age remained a significant predictor of brain infarcts (odds ratio 1.08, 95% CI1.02–1.14, P=0.004). After controlling for age and education, the presence of infarct was a significant predictor of impaired decision making on the Iowa Gambling Task of decision making (β −28.2, 95% CI −42.7 to −14.1, P<0.001).

Conclusions

Prevalence of infarcts on neuroimaging in this disadvantaged, community‐dwelling cohort was much higher than expected for age and was associated with impaired decision making. Further research is needed to identify individuals at highest risk who may benefit from targeted preventative strategies.

[Clonal evolution and clinical significance of trisomy 8 in acquired bone marrow failure]

Objective: To analyze clonal evolution and clinical significance of trisomy 8 in patients with acquired bone marrow failure. Methods: The clinical data of 63 patients with acquired bone marrow failure accompanied with isolated trisomy 8 (+8) from June 2011 to September 2018 were analyzed retrospectively, the clonal evolution patterns and relationship with immmunosuppressive therapy were summarized. Results: Totally 24 male and 39 female patients were enrolled, including 39 patients with aplastic anemia (AA) and 24 patients with relatively low-risk myelodysplastic syndrome (MDS) . Mean size of+8 clone in MDS patients[65% (15%-100%) ]was higher than that of AA patients[25% (4.8%-100%) , z=3.48, P=0.001]. The patients were was divided into three groups (<30%, 30%-<50%,and ≥50%) according to the proportion of+8 clone. There was significant difference among the three groups between AA[<30%:55.6% (20/36) ; 30-50%: 22.2% (8/36) ; ≥50%22.2% (8/36) ]and MDS patients[<30%:19.0% (4/21) ; 30%-<50%:19.0% (4/21) ; ≥50%61.9% (13/21) ] (P=0.007) . The proportion of AA patients with+8 clone <30% was significantly higher than that of MDS patients (P=0.002) ; and the proportion of AA patients with+8 clone ≥50%was significantly lower than that of MDS patients (P=0.002) . The median age of AA and MDS patients was respectively 28 (7-61) years old and 48.5 (16-72) years old. Moreover, there was no correlation between age and+8 clone size in AA or MDS (r(s)=0.109, P=0.125; r(s)=-0.022, P=0.924, respectively) . There was statistical difference in total iron binding capacity, transferrin and erythropoietin between high and low clone group of AA patients (P=0.016, P=0.046, P=0.012, respectively) , but no significant difference in MDS patients. The immunosuppressive therapy (IST) efficacy of AA and MDS patients was respectively 66.7% and 43.8% (P=0.125) . Comparing with initial clone size (27.3%) , the +8 clone size (45%) of AA patients was increased 1-2 year after IST, but no statistical difference (z=0.83, P=0.272) . Consistently, there was no significant change between initial clone size (72.5%) and 1-2 year clone size (70.5%) after IST in MDS patients. There was no significant difference in IST efficient rate between +8 clone size expansion and decline group of in AA patients at 0.5-<1, 1-2 and>2 years after IST. We found four dynamic evolution patterns of +8 clone, which were clone persistence (45%) , clone disappearance (30%) , clone emergence (10%) and clone recurrence (15%) . Conclusions: AA patients had a low clone burden, while MDS patients had a high burden of +8 clone. The +8 clone of AA patients didn't significantly expanded after IST, and the changes of +8 clone also had no effect on IST response.

Abstract WMP49: White Matter Hyperintensities in a High Risk Population Living in Marginal Housing (HOTEL study)

Background: White Matter Hyperintensities (WMH) are features of cerebral small vessel disease (cSVD) along with lacunes, cerebral microbleeds and perivascular spaces. Vascular risk factors account for only a small proportion of the variability of the presence of WMH, and the role of additional risk factors including drug use/dependence or infections is not well defined.

Objective: Examine prevalence and risk factors associated with WMH of presumed vascular origin within the HOTEL cohort, a population living in marginal housing with a high prevalence of prior homelessness, substance dependence, head trauma, mental illness and infectious diseases.

Methods: Baseline imaging on 3T MRI included T1, T2-FLAIR and SWI sequences. WMH not consistent with vascular origins were excluded. Two raters assessed WMH using the Fazekas scale. Participants were divided into those with or without moderate-severe WMH (periventricular Fazekas score >2 or deep score >1). Potential cSVD risk factors which were significant on univariate analysis were entered into a multivariable stepwise binomial logistic regression to identify independent risk factors for moderate-severe WMH.

Results: Intraclass coefficient for inter-rater reliability was 0.948 (95% CI, 0.924 to 0.965) for periventricular WMH and 0.848 (95% CI, 0.782 to 0.895) for deep WMH. Baseline prevalence of moderate-severe WMH (mean age 43.6 ± 9.5 years, 78% male) was 24.5%, much higher than in other, older healthy aging cohorts (Table). Age (OR 1.085, 95%CI 1.042-1.130), systolic blood pressure (OR 1.033, 95%CI 1.008-1.058) and regular injection drug use (OR 3.655, 95%CI 1.284-10.403) together explained 23.5% of variance in the presence of moderate-severe WMH within this population, with injection drug use having the largest effect.

Conclusions: This young cohort appears to have an accelerated burden of cSVD, with injected drug use as a major risk factor. Further research is needed to elucidate potential mechanisms.

Selenoprotein P and Yunnan endemic sudden cardiac death--an ecological study

The aim of the present study was to explore the role of selenoprotein P (SePP) in the etiology of the endemic sudden cardiac death in Yunnan, China. The levels of SePP of 124 subjects and glutathione peroxidase (GPx) of 119 subjects were measured. The subjects were from the old and new endemic areas and non-endemic areas. The levels of SePP and GPx of the subjects of the old endemic area were significantly higher than those of the subjects of the new endemic area and the non-endemic areas, respectively. The Pearson's correlation among SePP, GPx, and the number of the incident cases of the disease were statistically significant. These correlations show that there is an inverse relationship among the number of patients and the levels of SePP (r  =  - 0.9800, P  =  0.0200) and GPx (r  =  - 0.961, P  =  0.009). The results show that selenium deficiency might play an important role in the incidence of the disease.

Analysis of glutathione peroxidase 1 gene polymorphism and Keshan disease in Heilongjiang Province, China

Keshan disease (KD) is an endemic cardiomyopathy associated with selenium deficiency. Recent studies indicate that glutathione peroxidase 1 (GPx1) mutation decreases GPx activity in myocardial cells and increases the risk of KD. To further clarify the correlation between GPx1 polymorphism and KD, we analyzed GPx1 polymorphism, blood selenium levels and GPx activity in KD patients and healthy controls in Heilongjiang Province. Four and 24 new mutation loci in the promoter and the exon region, respectively, of the GPx1 gene were found in the subjects, in contrast with the previously reported loci. There were no significant differences in the mutation frequency of these loci between the KD group and controls (chi-square test; P > 0.05). However, the mutation frequency of exon 474 was higher in the KD group (7/36) than in controls (2/41), and GPx activity was lower in the mutation group (90.475 ± 23.757 U/L) than in the non-mutation group (93.947 ± 17.463 U/L). Further investigation is necessary to clarify a possible causality between GPx1 exon 474 mutation and KD.

Short axis contact in the chaining of ellipsoidal particles of polar molecule dominated electrorheological fluid

We simulate the effect of the chaining direction of ellipsoidal particles of polar molecule dominated electrorheological (PM-ER) fluids using commercially available COMSOL Multiphysics® software for the distribution of electric field and the total electrostatic energy. It is proved that adding ferroelectric materials to the channels parallel to the short axis would make the short axis parallel to the field direction when the ellipsoidal particles are chained under an electric field. According to our simulation, while the concentration of the channels stays constant, the greater the dielectric constant of the inserted material, the stronger the maximum local electric field will be.

A comparison study of detecting gold nanorods in living cells with confocal reflectance microscopy and two-photon fluorescence microscopy

Two-photon fluorescence microscopy and confocal reflectance microscopy were compared to detect intracellular gold nanorods in rat basophilic leukaemia cells. The two-photon photoluminescence images of gold nanorods were acquired by an 800 nm fs laser with the power of milliwatts. The advantages of the obtained two-photon photoluminescence images are high spatial resolution and reduced background. However, a remarkable photothermal effect on cells was seen after 30 times continuous scanning of the femto-second laser, potentially affecting the subcellular localization pattern of the nanorods. In the case of confocal reflectance microscopy the images of gold nanorods can be obtained with the power of light source as low as microwatts, thus avoiding the photothermal effect, but the resolution of such images is reduced. We have noted that confocal reflectance images of cellular gold nanorods achieved with 50 microW 800 nm fs have a relatively poor resolution, whereas the 50 microW 488 nm CW laser can acquire reasonably satisfactory 3D reflectance images with improved resolution because of its shorter wavelength. Therefore, confocal reflectance microscopy may also be a suitable means to image intracellular gold nanorods with the advantage of reduced photothermal effect.

On the Lorentz local electric field in soft-matter systems

In electric-field-responsive soft-matter systems, the suspended particles respond to the Lorentz local field (LLF), yielding abundant important phenomena. Even though the particles can easily rotate, the LLF was conventionally adopted as a quantity that is independent of rotations in the literature. In contrast, here we design an experiment to measure the LLF between two metallic spheres, one of which is rotating, and report a rotation-driven reduction. Excellent agreement between our experiment and theory reveals the role of the relaxation of dipole moments. Its relevance to biophysics, colloidal physics, and nonlinear physics is also discussed.

Structure of Electrorheological Fluids under an Electric Field and a Shear Flow: Experiment and Computer Simulation

It is known that macroscopic properties of colloidal suspensions are often determined by the microstructure of the particles in the suspensions, depending on the interparticle, Brownian, and hydrodynamic (if any) forces. We take electrorheological (ER) fluids as an example. By using a computer simulation and an experimental approach, we investigate the structure of ER fluids subjected to both an electric field and a shear flow. The microstructure evolution from random structure, to chains, and then to stable lamellar patterns, observed in the experiments, agrees very well with that obtained in the simulations. It is shown that the formation of such lamellar patterns originates from the difference between the dipole moment induced in the particles suspended in the ER fluids without shear and the one with shear. The results on the relaxation process of structural formation and the internal structure of layers are also presented. Thus, it seems possible to achieve various structures and hence desired macroscopic properties of colloidal suspensions by adjusting external fields and, simultaneously, a shear flow.

Effect of low power laser irradiation on disconnecting the membrane-attached hemoglobin from erythrocyte membrane

In our previous study we found that low power laser irradiation improved the erythrocyte deformability, but the mechanism is unclear. The membrane-attached hemoglobin (Hbm) may be one of the determining factors for the erythrocyte deformability. We report here for the first time, that laser irradiation can reduce the Hbm contents in pig's erythrocytes, providing the explanation for the improvement of erythrocyte deformability. The decrease of the Hbm was proportional to the irradiation dose, but the relative change of Hbm was saturated around 35%. The 532 nm laser was more efficient at lowering Hbm than the 632.8 nm laser, consistent with the absorption spectrum of Hbm.

A comparative study of 632.8 and 532 nm laser irradiation on some rheological factors in human blood in vitro

The effects of laser irradiation with 632.8 and 532 nm on rheological properties of blood were comparatively studied in vitro. Under the irradiation condition of 30 mW, laser irradiation of blood samples using a spot diameter of 5 mm with each laser, showed promising results in the modulation of hemorheological properties. When blood samples from patients with abnormally high values of erythrocyte sedimentation rate (ESR) were irradiated, the values of ESR were lowered statistically by either of the 632.8 or 532 nm lasers. The laser irradiation reduced blood viscosities at different shear rates (10-110 S(-1)) for the hyper-viscosity blood samples. Laser irradiation increased the electrophoretic mobility (EPM) of erythrocytes when the values of the sample's EPM were abnormally slow. The erythrocyte deformability was enhanced by laser irradiation when the deformability of the sample from the patients was originally poor. For verifying the improvement of laser irradiation on erythrocyte deformability, the typical erythrocyte samples with poor deformability were produced by the pre-treatment of the erythrocytes with Ca(2+). The deformability of these erythrocyte samples was also improved after laser irradiation. These results suggest that membrane-bound hemoglobin (Hbm) might be the initial site of the interaction, since Hbm is the main cause of poor deformability when erythrocytes were treated with Ca(2+). In all experiments including ESR, blood viscosity, EPM and erythrocyte deformability, the 532 nm laser demonstrated more efficient effects on modulating rheological properties than 632.8 nm laser. This wavelength effect is consistent with the absorption spectrum of hemoglobin, reflecting that hemoglobin may be one of the action targets under laser irradiation.

Cytosolic-Ca2+ and coxsackievirus B3-induced apoptosis in cultured cardiomyocytes of rats

AIM

To explore the role of cytosolic free calcium ([Ca2+]i) in apoptosis induced by coxsackievirus B3 (CVB3) in cultured cardiomyocytes of rats.

METHODS

Primary cultured cardiomyocyte was prepared from Wistar rats ages 2-3 d. The apoptosis in cardiomyocyte was determined by terminated deoxynucleotide transferase directed d-UTP nick and end labeling (TUNEL) method, and the apoptosis was observed under a transmission electron microscope. [Ca2+]i in single cardiomyocyte loaded with Fluo 3-AM was measured by confocal microsorope.

RESULTS

(1) The concentration of CVB3 in the medium reached the peak at 24 h after CVB3 infection. (2) The apoptotic cells were not found in CVB3-infected cardiomyocyte in first 10 h, but amounted to 5% at 17 h, 60% at 24 h, and 90% at 36 h. (3) The peak value of [Ca2+]i elevation reached at 17 h after CVB3 infection (P < 0.01). (4) The characteristics of apoptosis was also seen by transmission electron microscope.

CONCLUSION

CVB3 induced the apoptosis in cultured cardiomyocyte, and [Ca2+]i mobilization was involved in the signal transduction process in apoptosis cells, and played an important role especially in the early stage of apoptosis induced by CVB3.

Antisense RNA gene therapy for studying and modulating biological processes

Agents that produce their effects through an antisense mechanism offer the possibility of developing highly specific alternatives to traditional pharmacological antagonists, thereby providing a novel class of therapeutic agents, ones which act at the level of gene expression. Among the antisense compounds, antisense RNA produced intracellularly by an expression vector has been used extensively in the past several years. This review considers the advantages of the antisense RNA approach over the use of antisense oligodeoxynucleotides, the different means by which one may deliver and produce antisense RNA inside cells, and the experimental criteria one should use to ascertain whether the antisense RNA is acting through a true antisense mechanism. Its major emphasis is on exploring the potential therapeutic use of antisense RNA in several areas of medicine. For example, in the field of oncology antisense RNA has been used to inhibit several different target proteins, such as growth factors, growth factor receptors, proteins responsible for the invasive potential of tumor cells and proteins directly involved in cell cycle progression. In particular, a detailed discussion is presented on the possibility of selectively inhibiting the growth of tumor cells by using antisense RNA expression vectors directed to the individual calmodulin transcripts. Detailed consideration is also provided on the development and potential therapeutic applications of antisense RNA vectors targeted to the D2 dopamine receptor subtype. Studies are also summarized in which antisense RNA has been used to develop more effective therapies for infections with certain viruses such as the human immunodeficiency virus and the virus of hepatitis B, and data are reviewed suggesting new approaches to reduce elevated blood pressure using antisense RNA directed to proteins and receptors from the renin-angiotensin system. Finally, we outline some of the problems which the studies so far have yielded and some outstanding questions which remain to be answered in order to develop further antisense RNA vectors as therapeutic agents.

Isolation and characterization of a new gene, sre, which encodes a GATA-type regulatory protein that controls iron transport in Neurospora crassa

Multiple GATA factors - regulatory proteins with consensus zinc finger motifs that bind to DNA elements containing a GATA core sequence - exist in the filamentous fungus Neurospora crassa. One GATA factor, NIT2. controls nitrogen metabolism, whereas two others, WC-1 and WC-2, regulate genes responsive to blue light induction. A gene encoding a new GATA factor, named SRE, was isolated from Neurospora using a PCR-mediated method. Sequence analysis of the new GATA factor gene revealed an ORF specifying 587 amino acids, which is interrupted by two small introns. Unlike all previously known Neurospora GATA factors, which possess a single zinc-finger DNA-binding motif, SRE contains two GATA-type zinc fingers. The deduced amino acid sequence of SRE shows significant similarity to URBSI of Ustilago and SREP of Penicillium. A loss-of-function mutation was created by the RIP procedure. Analysis of sre+ and sre- strains revealed that SRE acts as a negative regulator of iron uptake in Neurospora by controlling the synthesis of siderophores. Siderophore biosynthesis is repressed by high iron concentrations in the wild-type strain but not in sre- mutant cells. The sre promoter contains a number of GATA sequences; however, expression of sre mRNA occurs in a constitutive fashion and is not regulated by the concentration of iron available to the cells.

[Chemical constituents of Phyllanthus urinaria L. and its antiviral activity against hepatitis B virus]

Studies on the chemical constituents of Phyllanthus urinaria and its antiviral activity against hepatitis B virus were completed. Eleven compounds have been isolated. Two of them are new compounds methyl ester dehydrochebulic acid and methyl brevifolin carboxylate. Antiviral experiments on HBsAg in vitro and liver damage caused by CCl4 have shown that. Phyllanthus urinaria possesses antiviral activities against HBV.

D2 dopamine antisense RNA expression vector, unlike haloperidol, produces long-term inhibition of D2 dopamine-mediated behaviors without causing Up-regulation of D2 dopamine receptors

Long-term inhibition of D2 dopamine receptors using classic D2 dopamine receptor antagonists such as haloperidol often causes a compensatory up-regulation of the D2 dopamine receptors. We investigated whether the long-term inhibition of D2 dopamine receptors using an eukaryotic expression vector housing a cDNA sequence encoding an antisense RNA directed to the D2 dopamine receptor transcript (D2 antisense vector) would also produce up-regulation of the D2 receptors. Single, bilateral injections of the D2 antisense vector into the corpora striata of mice inhibited the stereotypy induced by acute challenge injections with the D2/D3 dopamine receptor agonist quinpirole but did not inhibit the grooming induced by acute challenge injections with the D1 agonist SKF 38393. Similar treatment with the D2 antisense vector produced a long-term (>1 month) cataleptic response without producing tolerance to challenge injections with haloperidol. By contrast, catalepsy induced by a single injection of haloperidol lasted only approximately 2 days, and tolerance developed to its effects after long-term treatment. Repeated treatment of mice with haloperidol resulted in an inhibition of apomorphine-induced climbing behavior throughout the time of treatment with haloperidol, but the climbing behavior markedly increased to levels significantly higher than that of the control mice immediately after withdrawal from haloperidol treatment. This increased climbing was accompanied by increased levels of D2 dopamine receptors in the striatum. By contrast, single, bilateral intrastriatal injections of the D2 antisense vector significantly inhibited apomorphine-induced climbing for approximately 30 days but failed to increase the climbing behavior or the levels of D2 dopamine receptors in striatum over those of the control values. These results suggest that a single injection of a D2 antisense RNA expression vector into mouse striatum produces specific, long-term inhibition of D2 dopamine receptor behaviors without causing a compensatory increase in the levels or function of D2 dopamine receptors.

Expression of a D2 dopamine receptor antisense RNA in brain inhibits D2-mediated behaviors

Drugs currently used to treat disorders of dopamine-mediated behaviors in the central nervous system are non-selective in that they interact not only with more than one isoform of dopamine receptor but also with receptors for other neurotransmitters. A new strategy to inhibit the actions of individual dopamine receptor subtypes is to inhibit the synthesis of the receptors through the use of oligonucleotides antisense to the transcripts encoding the different receptors. Earlier studies showed that oligodeoxynucleotides antisense to the D1 or D2 dopamine receptor messenger RNAs specifically inhibited the biological actions mediated by these individual isoforms of the dopamine receptor. However, these actions were relatively short-lasting. To determine whether one can achieve long-lasting inhibition of dopamine responses, while still taking advantage of the highly selective nature of an antisense strategy, an expression vector was employed that generates antisense RNA to the transcript encoding the D2 dopamine receptor. A single intrastriatal injection of this vector generated an antisense RNA to the D2 dopamine receptor, selectively reduced the levels of D2 dopamine receptors, and caused selective, long-term inhibition of behaviors mediated by D2 dopamine agonists. Such an antisense RNA strategy may find use in studying the function of dopaminergic receptors and in disorders associated with dopaminergic hyperactivity.

Antisense strategies in dopamine receptor pharmacology

Recent advances in molecular biology have provided pharmacologists the opportunity of developing an entirely new type of agent for studying and treating a variety of biological disorders. These agents, termed antisense oligodeoxynucleotides, have as their target the messenger RNAs encoding specific proteins. They act by binding to selected portions of these mRNAs through complimentary interactions and thereby prevent the synthesis of these proteins. These novel pharmacological tools have the promise of being easier to design and being more selective and predictable in their actions. In addition, insofar as agents targeted to receptors for neurotransmitters are concerned, unlike the classical pharmacological agents, these new compounds may not lead to the upregulation of the very receptors the drugs are designed to inhibit. The present review summarizes briefly studies on the effect of oligodeoxynucleotides antisense to the mRNAs encoding the various subtypes of the dopamine receptor. The studies show that oligodeoxynucleotides antisense to the D2 dopamine receptor when intracerebroventricularly into brains of rodents are rapidly taken up into the brain tissue, distributed to brain cells, and produce effects characteristic of highly selective D2 dopamine antagonists. The compounds also produced specific reductions in the levels of D2 dopamine receptor mRNA and D2 dopamine receptors. Similarly, injecting an antisense oligodeoxynucleotide targeted to the D1 dopamine receptor mRNA produces effects characteristic of D1 dopamine receptor antagonists. Other studies using these agents has produced evidence that there is a small pool of receptors that turn over very rapidly and which constitute the functional pool of these receptors. The evidence suggests further that antisense oligodeoxynucleotides inhibit the synthesis of this small functional pool of dopamine receptors, thereby providing an explanation of why there is often a discordance between changes in dopaminergic function and changes in the levels of dopamine receptors. Studies of antisense oligodeoxynucleotides targeted to the other subtypes of dopamine receptor may help reveal the biological roles that these and other newly discovered subtypes of neurotransmitter receptors have. They may also provide an entirely new and potentially more selective therapeutic regimen for altering the functions of these receptors.

Intrastriatal administration of an oligodeoxynucleotide antisense to the D2 dopamine receptor mRNA inhibits D2 dopamine receptor-mediated behavior and D2 dopamine receptors in normal mice and in mice lesioned with 6-hydroxydopamine

Previous studies have shown that the intracerebroventricular injection of antisense oligodeoxynucleotides targeted to the mRNAs encoding the different subtypes of dopamine receptors inhibited behaviors mediated by these receptors. The present studies were designed to determine whether such antisense oligodeoxynucleotides could produce similar effects when injected into a discrete brain area. A D2 dopamine receptor antisense oligodeoxynucleotide (D2 antisense) was repeatedly injected into one corpus striatum of either normal mice or mice with unilateral lesions of the striatum induced by 6-hydroxydopamine. In the latter, intrastriatal injection of D2 antisense blocked the contralateral rotational behavior induced by the parenteral administration of the D2 dopamine receptor agonist quinpirole. The inhibitory effect of D2 antisense was dose- and time-related and was reversed upon cessation of D2 antisense treatment. This inhibitory effect was also selective in that D2 antisense treatment inhibited the rotational behavior induced by quinpirole but not that induced by the D1 dopamine receptor agonist SKF 38393 or by the muscarinic cholinergic agonist oxotremorine. Following repeated intrastriatal injections of D2 antisense into normal mice, parenteral administration of quinpirole caused rotational behavior ipsilateral to the side in which the D2 antisense was injected. No such rotational behavior was seen when similarly treated mice were challenged with SKF 38393 or oxotremorine. The quinpirole-induced rotational behavior in mice given intrastriatal injections of D2 antisense disappeared upon cessation of D2 antisense treatment. Repeated intrastriatal administration of D2 antisense also caused a significant reduction in the levels of D2, but not D1, dopamine receptors in striatum, as determined by receptor autoradiography. The levels of D2 dopamine receptors returned to normal upon cessation of D2 antisense treatment. Intrastriatal administration of an oligodeoxynucleotide with randomly placed nucleotides failed to alter the rotational response to quinpirole in either 6-hydroxydopamine-lesioned or normal mice and failed to alter the levels of D2 dopamine receptors in striatum. These results show that selective inhibition of behavioral responses mediated by D2 dopamine receptors can be achieved by the direct injection of a D2 antisense oligodeoxynucleotide into a discrete brain area.

D2 dopamine receptor antisense increases the activity and mRNA of tyrosine hydroxylase and aromatic L-amino acid decarboxylase in mouse brain

A D2 dopamine receptor antisense oligodeoxynucleotide was administered intracerebrovetricularly to mice twice on the first day and then once daily for 2 days. The animals were killed 2 h after the last injection, and tyrosine hydroxylase and aromatic L-amino acid decarboxylase activities assayed in the corpus striatum, olfactory tubercle and frontal cortex. Tyrosine hydroxylase activity increased in corpus striatum but not in the olfactory tubercle or in the frontal cortex, while the activity of aromatic L-amino acid decarboxylase increased in all three brain regions. The treatment with the antisense oligomer also elevated the mRNA levels for the two enzymes in the midbrain. In contrast, repeated injection of a vehicle or a random oligomer was without effect on enzyme activity or mRNA D2 antisense oligodeoxynucleotides appear to be selective tools to investigate the role of D2 dopamine receptors in brain.

Uptake and distribution of fluorescein-labeled D2 dopamine receptor antisense oligodeoxynucleotide in mouse brain

To determine the uptake and distribution of oligodeoxynucleotides in brain, a 20-mer phosphorothioated oligodeoxynucleotide complementary to a portion of the D2 dopamine receptor mRNA was fluorescently labeled with fluorescein isothiocyanate (FITC) and injected into the lateral cerebral ventricles of mice. At various survival times after the injection, the brains were removed, fixed, sectioned, and viewed under a fluorescent microscope. The results showed that the oligodeoxynucleotide was rapidly taken up into the brain. Initially the label was relatively diffusely spread throughout the interstitial spaces of the brain, then became redistributed to the cellular compartments. The signal extended from those forebrain nuclei located immediately in contact with the ventricles, such as the corpus striatum, septum, and hippocampus, to areas further removed from the ventricles, such as the cerebral cortex, nucleus accumbens, and substantia nigra. When the FITC-labeled D2 antisense oligodeoxynucleotide was given once daily for 4 d, the signal intensity seen 24 h after the last injection appeared to be of greater intensity overall compared to that seen after a single injection. At early time-points the oligodeoxynucleotide signals appeared to be punctuated and were found in cell bodies as well as in proximal dendritic processes. However, not all cells were equally labeled, suggesting an uneven uptake and accumulation of the D2 antisense into the various cell types. At later time-points the fluorescent signal appeared granular; at these times the injected material was largely degraded. These studies show that a D2 dopamine receptor antisense oligodeoxynucleotide is rapidly taken up from cerebral ventricles into brain, becomes widely distributed throughout the brain tissue to areas far removed from direct contact with the ventricles, and appears to accumulate to a different extent in the various brain areas and cell types.

D2 dopamine receptor antisense oligodeoxynucleotide inhibits the synthesis of a functional pool of D2 dopamine receptors

In vivo administration of an antisense oligonucleotide targeted toward the D2 dopamine (DA) receptor mRNA (D2 AS) markedly inhibited D2 receptor-mediated behaviors but produced only a relatively small reduction in the levels of D2 DA receptors in mouse striatum. This apparent dissociation between DA receptor-mediated behaviors and the levels of D2 DA receptors was addressed by inhibiting the total number of D2 DA receptors by intraperitoneal administration of the selective, irreversibly acting D2 DA receptor antagonist fluphenazine-N-mustard (FNM) and then determining the effects of D2 AS, administered intracerebroventricularly, on the rate of synthesis of D2 DA receptors and on the recovery of D2 receptor-mediated behaviors. FNM inactivated approximately 90% of D2 DA receptors within 4 hr of treatment, after which the receptors returned to normal levels by approximately 8 days. D2 AS treatment significantly inhibited the rate of recovery of D2 DA receptors in striatum of FNM-treated mice. FNM treatment also produced a number of behavioral alterations, including catalepsy, and the inhibition of stereotypic behavior induced by the D2/D3 DA receptor agonist quinpirole. Both of these behaviors returned to normal within 8 days after FNM treatment. D2 AS treatment delayed the restoration of these FNM-induced behaviors. Thus, it reduced the rate of disappearance of the cataleptic behavior induced by FNM and significantly delayed the restoration of the stereotypic behavior induced by quinpirole. The changes induced by D2 AS on D2 receptor-mediated behaviors were reversed on cessation of D2 AS treatment. A random oligomer given in the same amount and for the same length of time as that of the D2 AS had no significant effects on either D2 DA receptor synthesis or DA receptor-mediated behaviors. These studies demonstrate that in vivo administration of D2 AS decreased the rate of recovery of D2 DA receptors and inhibited the recovery of D2 DA receptor-mediated behaviors after irreversible receptor inactivation and suggest that D2 AS treatment inhibits the synthesis of a functional pool of D2 DA receptors.