Coronary artery calcium as a marker of healthy and unhealthy aging in adults aged 75 and older: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Coronary artery calcium (CAC) is validated for risk prediction among middle-aged adults, but there is limited research exploring implications of CAC among older adults. We used data from the Atherosclerosis Risk in Communities (ARIC) study to evaluate the association of CAC with domains of healthy and unhealthy aging in adults aged ≥75 years.

METHODS

We included 2,290 participants aged ≥75 years free of known coronary heart disease who underwent CAC scoring at study visit 7. We examined the cross-sectional association of CAC = 0, 1-999 (reference), and ≥1000 with seven domains of aging: cognitive function, hearing, ankle-brachial index (ABI), pulse-wave velocity (PWV), forced vital capacity (FVC), physical functioning, and grip strength.

RESULTS

The mean age was 80.5 ± 4.3 years, 38.6% male, and 77.7% White. 10.3% had CAC = 0 and 19.2% had CAC≥1000. Individuals with CAC = 0 had the lowest while those with CAC≥1000 had the highest proportion with dementia (2% vs 8%), hearing impairment (46% vs 67%), low ABI (3% vs 18%), high PWV (27% vs 41%), reduced FVC (34% vs 42%), impaired grip strength (66% vs 74%), and mean composite abnormal aging score (2.6 vs 3.7). Participants with CAC = 0 were less likely to have abnormal ABI (aOR:0.15, 95%CI:0.07-0.34), high PWV (aOR:0.57, 95%CI:0.41-0.80), and reduced FVC (aOR:0.69, 95%CI:0.50-0.96). Conversely, participants with CAC≥1000 were more likely to have low ABI (aOR:1.74, 95%CI:1.27-2.39), high PWV (aOR:1.52, 95%CI:1.15-2.00), impaired physical functioning (aOR:1.35, 95%CI:1.05-1.73), and impaired grip strength (aOR:1.46, 95%CI:1.08-1.99).

CONCLUSIONS

Our findings highlight CAC as a simple measure broadly associated with biological aging, with clinical and research implications for estimating the physical and physiological aging trajectory of older individuals.

[Evaluation of differences in quality of life in patients with chronic graft-versus-host disease]

Objective: To evaluate the status of, differences in, and factors influencing quality of life (QoL) in patients with chronic graft-versus-host disease (GVHD). Methods: From September 2021 to February 2023, a cross-sectional study of 140 patients with chronic GVHD was conducted at our center. Symptom burden was assessed by the Lee Symptomatology Scale (LSS), and QoL was assessed by the Medical Outcome Study 36-Item Short-Form Health Survey (SF-36) (version 1) and five-level EuroQoL five-dimensional questionnaire (EQ-5D-5L). Results: Data from 140 respondents, including 32 (22.9%) with mild chronic GVHD, 87 (62.1%) with moderate chronic GVHD, and 21 (15.0%) with severe chronic GVHD, were analyzed. Of the respondents, 61.4% were male, and the median transplantation age was 34 (15-68) years. The primary diagnoses were acute myeloid leukemia (50.0%), acute lymphoblastic leukemia (20.0%), and myelodysplastic syndrome (15.0%). The common chronic GVHD-affected organs included the skin in 74 patients (52.9%), the eyes in 57 patients (40.7%), and the liver in 50 patients (35.7%). Among the whole cohort, the eye (20.48±23.75), psychological (16.13±17.00), and oral (13.66±20.55) scores were highest in the LSS group. The physiological function (36.07±11.13), social function (36.10±10.68), and role-emotional functioning (38.36±11.88) scores were lowest in the SF-36 group. The EQ-5D index was 0.764. The total LSS scores for mild, moderate, and severe chronic GVHD were 6.51±6.15, 10.07±5.61, and 20.90±10.09, respectively. The SF-36 physical component scores (PCSs) were 43.12±6.38, 40.73±7.14, and 36.97±6.97, respectively, and the mental component scores (MCSs) were 43.00±8.47, 38.90±9.52, and 28.96±9.63, respectively. The EQ-5D values were 0.810±0.124, 0.762±0.179, and 0.702±0.198, respectively. The multivariate analysis showed that the overall symptom burden (β=-0.517), oral symptom burden (β=-0.456), National Institute of Health (NIH) criteria for the eyes (β=-0.376), and nutrition-related symptom burden (β=-0.211) were significantly negatively correlated with the PCS. The NIH score (β=-0.260) was negatively correlated with the MCS score. Oral symptom burden (β=-0.400), joint/fascia NIH criteria (β=-0.332), number of involved systems (β=-0.253), overall NIH criteria (β=-0.205), and number of immunosuppressants taken (β=-0.171) were significantly negatively correlated with the EQ-5D score (all P<0.05). Medium to strong correlations were found between the EQ-5D score and the SF-36 score (|r|=0.384-0.571, P<0.001). Conclusions: The QoL of patients with chronic GVHD is impaired, and the more severe the disease, the poorer the QoL. Overall symptom burden, severity of eyes, and oral symptom burden were the most important factors affecting QoL.

Development of an adaptive clinical web-based prediction tool for kidney replacement therapy in children with chronic kidney disease

Clinicians need improved prediction models to estimate time to kidney replacement therapy (KRT) for children with chronic kidney disease (CKD). Here, we aimed to develop and validate a prediction tool based on common clinical variables for time to KRT in children using statistical learning methods and design a corresponding online calculator for clinical use. Among 890 children with CKD in the Chronic Kidney Disease in Children (CKiD) study, 172 variables related to sociodemographics, kidney/cardiovascular health, and therapy use, including longitudinal changes over one year were evaluated as candidate predictors in a random survival forest for time to KRT. An elementary model was specified with diagnosis, estimated glomerular filtration rate and proteinuria as predictors and then random survival forest identified nine additional candidate predictors for further evaluation. Best subset selection using these nine additional candidate predictors yielded an enriched model additionally based on blood pressure, change in estimated glomerular filtration rate over one year, anemia, albumin, chloride and bicarbonate. Four additional partially enriched models were constructed for clinical situations with incomplete data. Models performed well in cross-validation, and the elementary model was then externally validated using data from a European pediatric CKD cohort. A corresponding user-friendly online tool was developed for clinicians. Thus, our clinical prediction tool for time to KRT in children was developed in a large, representative pediatric CKD cohort with an exhaustive evaluation of potential predictors and supervised statistical learning methods. While our models performed well internally and externally, further external validation of enriched models is needed.

[Study on the correlation between type 2 diabetes mellitus combined with non-alcoholic steatohepatitis and aerobic exercise performance]

Objective: To study the correlation between patients with type 2 diabetes mellitus combined with nonalcoholic steatohepatitis in order to provide theoretical support for the treatment of NAFLD through aerobic exercise performance. Methods: 253 cases with T2DM combined with NAFLD were selected. 93 cases consented to undergo a liver biopsy. Among them, 74 cases with liver biopsy successfully passed the symptom-limited cardiopulmonary exercise test (CPET) and respiratory quotient (RQ)≥1.05. Patients were divided into two groups according to the NAFLD activity score (NAS) of the pathological biopsy: the non-NASH group (NAS < 4) and the NASH group (NAS≥4). The differences in general clinical and biochemical indicators and exercise parameters were compared between the two groups. The relevant factors that affect aerobic exercise performance in NAFLD patients were explored by correlation and regression analysis. Results: The peak oxygen uptake [VO2 @ peak, (17.82 ± 5.61) ml·kg(-1)·min(-1) and (23.14 ± 5.86) ml·kg(-1)·min(-1)] and anaerobic threshold [VO2 @ AT, (11.47 ± 3.12) ml·kg(-1)·min(-1) and (13.81 ± 3.53) ml·kg(-1)·min(-1)] were lower in the NASH group than those in the non-NASH group in T2DM patients, with P < 0.01, indicating a significant decrease in aerobic exercise performance in NASH patients compared to non-NASH patients. Correlation analysis showed that patients with T2DM combined with NAFLD VO2@peak was positively correlated with RQ, carbohydrate oxidation rate (%CHO), daily carbohydrate energy supply (CHO Kcal/d), high-density lipoprotein cholesterol (HDL-C), and maximal voluntary ventilation (MVV) (r 0.360, 0.334, 0.341, 0.255, 0.294, P < 0.05 or P < 0.01, respectively) and negatively correlated with NAS score, fat attenuation, liver stiffness, fat oxidation rate (%FAT), daily fat energy supply (FAT Kcal/d), aspartate aminotransferase (AST), alanine aminotransferase (ALT), body mass, and body mass index (BMI) (r -0.558, -0.411, -0.437, -0.340, -0.270, -0.288, -0.331, -0.295, -0.469, P < 0.05 or P < 0.01, respectively). VO2@AT were positively correlated with RQ, %CHO, total cholesterol (TC), and HDL-C (r 0.351, 0.247, 0.303, 0.380, P < 0.05 or P < 0.01, respectively), while it was negatively correlated with NAS score, fat attenuation, liver stiffness, %FAT, FAT (Kcal/d), ferritin (Fer), ALT, AST, body weight, and BMI (r -0.330, -0.384, -0.428, -0.270, -0.318, 0.320, -0.404, -0.416, -0.389, -0.520, P < 0.05 or P < 0.01, respectively). Stepwise multiple regression analyses revealed that BMI, RQ, and NAS scores were independent correlated factors of aerobic exercise performance. Conclusion: Hepatic inflammation and fibrosis affect the aerobic exercise performance of patients with T2DM combined with NAFLD.

Defining Demographic-specific Coronary Artery Calcium Percentiles in the Population Aged ≥75: The ARIC Study and MESA

BACKGROUND

Current clinical guidelines recommend a coronary artery calcium (CAC) score of 100 Agatston Units or demographic-specific 75th percentile as high-risk thresholds for guiding atherosclerotic cardiovascular disease preventive therapy. Meanwhile, low CAC can help derisk individuals who may safely defer statin therapy. However, limited data from the early 2000s, including just 208 older Black individuals, inform CAC percentiles for adults aged 75 to 85 years, and none have been established in adults aged ≥85 years. This study aims to characterize the distribution of CAC and establish demographic-specific CAC percentiles in the population aged ≥75 years.

METHODS

We assessed 2886 participants aged ≥75 years without clinical coronary heart disease from the ARIC study (Atherosclerosis Risk in Communities) visit 7 (2018-2019; n=2217) and the MESA (Multi-Ethnic Study of Atherosclerosis) visit 5 (2010-2011; n=669). Prevalence of any CAC >0 and sex- and race-specific CAC percentiles across age were estimated nonparametrically with locally weighted regression models and pooled residual ranking.

RESULTS

The median age was 80 (interquartile interval, 77-83) years, and 60% were female. The prevalence of zero CAC was lowest in White males (4%), followed by Black males (13%), White females (14%), and highest in Black females (18%). Regardless of sex and race, most participants had CAC>100 (62.5%). CAC scores increased with age, with CAC identified in ≈95% of participants aged ≥90 years across sex-race subgroups. The 75th percentile corresponded to higher CAC scores for Black older adults (n=741), especially females, than currently used thresholds.

CONCLUSIONS

In community-dwelling adults aged ≥75 years free of clinical coronary heart disease, the prevalence of zero CAC was 11%, and CAC >100 as a threshold for high ASCVD risk would categorize most of this older population as high risk. Demographic-specific CAC percentiles from this study are a valuable tool for interpreting CAC in the population aged ≥75 years.

Coronary Artery Calcium Scores in Older Adults With Diabetes and Their Association With Diabetes-Specific Risk Enhancers (from the Atherosclerosis Risk in Communities Study)

Coronary artery calcium (CAC) is a validated marker of atherosclerotic cardiovascular disease (ASCVD) risk; however, it is not routinely incorporated in ASCVD risk prediction in older adults with diabetes. We sought to assess the CAC distribution among this demographic and its association with "diabetes-specific risk enhancers," which are known to be associated with increased ASCVD risk. We used the ARIC (Atherosclerosis Risk in Communities) study data, including adults aged >75 years with diabetes, who had their CAC measured at ARIC visit 7 (2018 to 2019). The demographic characteristics of participants and their CAC distribution were analyzed using descriptive statistics. Multivariable-adjusted logistic regression models were used to estimate the association between diabetes-specific risk enhancers (duration of diabetes, albuminuria, chronic kidney disease, retinopathy, neuropathy, and ankle-brachial index) and elevated CAC, adjusting for age, gender, race, education level, dyslipidemia, hypertension, physical activity, smoking status, and family history of coronary heart disease. The mean age in our sample was 79.9 (SD 3.97) years, with 56.6% women and 62.1% White. The CAC scores were heterogenous, and the median CAC score was higher in participants with a greater number of diabetes risk enhancers, regardless of gender. In the multivariable-adjusted logistic regression models, participants with ≥2 diabetes-specific risk enhancers had greater odds of elevated CAC than those with <2 (odds ratio 2.31, 95% confidence interval 1.34 to 3.98). In conclusion, the distribution of CAC was heterogeneous among older adults with diabetes, with the CAC burden associated with the number of diabetes risk-enhancing factors present. These data may have implications for prognostication in older patients with diabetes and supports the possible incorporation of CAC in the assessment of cardiovascular disease risk in this population.

Abstract MP14: Association Between Housing Insecurity With Reduced Access to Healthcare and Cardiovascular Disease Prevention: The Behavior Risk Factor Surveillance System (BRFSS) Study

Introduction: Risk factors including hypertension and hyperlipidemia increase the risk of cardiovascular disease (CVD). Yet, the significantly increased prevalence of CVD in housing insecure populations cannot be explained by the diagnosed prevalence of these risk factors alone. These populations may face unique barriers to care related to lack of access to screening, prevention, and treatment that complicate heart health.

Hypothesis: Access to quality healthcare and CVD prevention is reduced for the housing insecure population, independent of income and sociodemographic factors, compared to housing secure populations.

Methods: Using data from the 2017 Behavior Risk Factor Surveillance System (BRFSS), housing insecurity was self-reported as not being able to pay mortgage, rent, or utility bills over the past 12 months. Weighted multivariable logistic regressions were used to calculate adjusted odds ratios for the healthcare access variables.

Results: In our study population, 8.79% (51.8% female, 71.7% white) experienced housing insecurity. Compared to housing secure individuals, housing insecure individuals were more likely to not have a primary care doctor (OR 1.25 [1.16-1.35]), be unable to afford doctor visits (3.89 [3.63-4.16]), report pending medical bills (2.62 [2.33-2.93]), have Medicare (1.26 [1.01-1.57]) or Medicaid (1.83 [1.46-2.28]), experience gaps in healthcare coverage (2.94 [2.45-3.53]), delayed medical care (2.38 [2.10-2.70]), and were 4 times more likely to not take medications as prescribed due to cost (4.39 [3.86-4.99]). Among those with known hypertension and hypercholesterolemia, respectively, people experiencing housing insecurity were more likely to not be taking antihypertensive (1.35 [1.20-1.51]) and cholesterol-lowering medications (1.33 [1.18-1.48]).

Conclusion: Housing insecure populations experience significant healthcare access disparities, potentially exacerbating health outcomes through the underdiagnosis, prevention, and treatment of CVD.

Sex-and race-specific burden of aortic valve calcification among older adults without overt coronary heart disease: The Atherosclerosis Risk in Communities Study

BACKGROUND AND AIMS

The prevalence of aortic valve calcification (AVC) increases with age. However, the sex-and race-specific burden of AVC and associated cardiovascular risk factors among adults ≥75 years are not well studied.

METHODS

We calculated the sex-and race-specific burden of AVC among 2283 older Black and White adults (mean age:80.5 [SD:4.3] years) without overt coronary heart disease from the Atherosclerosis Risk in Communities Study who underwent non-contrast cardiac-gated CT-imaging at visit 7 (2018-2019). Using Poisson regression with robust variance, we calculated the adjusted prevalence ratios (aPR) of the association of AVC with cardiovascular risk factors.

RESULTS

The overall AVC prevalence was 44.8%, with White males having the highest prevalence at 58.2%. The prevalence was similar for Black males (40.5%), White females (38.9%), and Black females (36.8%). AVC prevalence increased significantly with age among all race-sex groups. The probability of any AVC at age 80 years was 55.4%, 40.0%, 37.3%, and 36.2% for White males, Black males, White females, and Black females, respectively. Among persons with prevalent AVC, White males had the highest median AVC score (100.9 Agatston Units [AU]), followed by Black males (68.5AU), White females (52.3AU), and Black females (46.5AU). After adjusting for cardiovascular risk factors, Black males (aPR:0.53; 95%CI:0.33-0.83), White females (aPR:0.68; 95%CI:0.61-0.77), and Black females (aPR:0.49; 95%CI:0.31-0.77) had lower AVC prevalence compared to White males. In addition, systolic blood pressure, non-HDL-cholesterol, and lipoprotein (a) were independently associated with AVC, with no significant race/sex interactions.

CONCLUSIONS

AVC, although highly prevalent, was not universally present in this cohort of older adults. White males had ∼50-60% higher prevalence than other race-sex groups. Moreover, cardiovascular risk factors measured in older age showed significant association with AVC.

Lipoprotein(a) and Subclinical Vascular and Valvular Calcification on Cardiac Computed Tomography: The Atherosclerosis Risk in Communities Study

Background Lipoprotein(a) (Lp(a)) is a potent causal risk factor for cardiovascular events and mortality. However, its relationship with subclinical atherosclerosis, as defined by arterial calcification, remains unclear. This study uses the ARIC (Atherosclerosis Risk in Communities Study) to evaluate the relationship between Lp(a) in middle age and measures of vascular and valvular calcification in older age. Methods and Results Lp(a) was measured at ARIC visit 4 (1996-1998), and coronary artery calcium (CAC), together with extracoronary calcification (including aortic valve calcium, aortic valve ring calcium, mitral valve calcification, and thoracic aortic calcification), was measured at visit 7 (2018-2019). Lp(a) was defined as elevated if >50 mg/dL and CAC/extracoronary calcification were defined as elevated if >100. Logistic and linear regression models were used to evaluate the association between Lp(a) and CAC/extracoronary calcification, with further stratification by race. The mean age of participants at visit 4 was 59.2 (SD 4.3) years, with 62.2% women. In multivariable adjusted analyses, elevated Lp(a) was associated with higher odds of elevated aortic valve calcium (adjusted odds ratio [aOR], 1.82; 95% CI, 1.34-2.47), CAC (aOR, 1.40; 95% CI, 1.08-1.81), aortic valve ring calcium (aOR, 1.36; 95% CI, 1.07-1.73), mitral valve calcification (aOR, 1.37; 95% CI, 1.06-1.78), and thoracic aortic calcification (aOR, 1.36; 95% CI, 1.05-1.77). Similar results were obtained when Lp(a) and CAC/extracoronary calcification were examined on continuous logarithmic scales. There was no significant difference in the association between Lp(a) and each measure of calcification by race or sex. Conclusions Elevated Lp(a) at middle age is significantly associated with vascular and valvular calcification in older age, represented by elevated CAC, aortic valve calcium, aortic valve ring calcium, mitral valve calcification, thoracic aortic calcification. Our findings encourage assessing Lp(a) levels in individuals with increased cardiovascular disease risk, with subsequent comprehensive vascular and valvular assessment where elevated.

Association of Non-Pharmaceutical Interventions to Reduce the Spread of SARS-CoV-2 With Anxiety and Depressive Symptoms: A Multi-National Study of 43 Countries

Objectives: To examine the association of non-pharmaceutical interventions (NPIs) with anxiety and depressive symptoms among adults and determine if these associations varied by gender and age. Methods: We combined survey data from 16,177,184 adults from 43 countries who participated in the daily COVID-19 Trends and Impact Survey via Facebook with time-varying NPI data from the Oxford COVID-19 Government Response Tracker between 24 April 2020 and 20 December 2020. Using logistic regression models, we examined the association of [1] overall NPI stringency and [2] seven individual NPIs (school closures, workplace closures, cancellation of public events, restrictions on the size of gatherings, stay-at-home requirements, restrictions on internal movement, and international travel controls) with anxiety and depressive symptoms. Results: More stringent implementation of NPIs was associated with a higher odds of anxiety and depressive symptoms, albeit with very small effect sizes. Individual NPIs had heterogeneous associations with anxiety and depressive symptoms by gender and age. Conclusion: Governments worldwide should be prepared to address the possible mental health consequences of stringent NPI implementation with both universal and targeted interventions for vulnerable groups.

[Clinical characteristics of human adenovirus infection in hospitalized children with acute respiratory infection in Beijing]

Objective: To compare the clinical characteristics of different types of human adenovirus (HAdV) infection in hospitalized children with acute respiratory infection in Beijing, and to clarify the clinical necessity of adenovirus typing. Methods: In a cross-sectional study, 9 022 respiratory tract specimens collected from hospitalized children with acute respiratory infection from November 2017 to October 2019 in Affiliated Children's Hospital, Capital Institute of Pediatrics were screened for HAdV by direct immunofluorescence (DFA) and (or) nucleic acid detection. Then the Penton base, Hexon and Fiber gene of HAdV were amplified from HAdV positive specimens to confirm their HAdV types by phylogenetic tree construction. Clinical data such as laboratory results and imaging data were analyzed for children with predominate type HAdV infection using t, U, or χ² test. Results: There were 392 cases (4.34%) positive for HAdV among 9 022 specimens from hospitalized children with acute respiratory infection. Among those 205 cases who were successfully typed, 131 were male and 74 were female, age of 22.6 (6.7, 52.5) months,102 cases (49.76%) were positive for HAdV-3 and 86 cases (41.95%), HAdV-7, respectively, while 17 cases were confirmed as HAdV-1, 2, 4, 6, 14 or 21. In comparison of clinical characteristics between the predominate HAdV type 7 and 3 infection, significant differences were shown in proportions of children with wheezing (10 cases (11.63%) vs. 25 cases (24.51%)), white blood cell count >15 ×10⁹/L (4 cases (4.65%) vs.14 cases (13.73%)), white blood cell count <5×10⁹/L (26 cases (30.23%) vs.11 cases (10.78%)), procalcitonin level>0.5 mg/L (43 cases (50.00%) vs. 29 cases (28.43%)), multilobar infiltration (45 cases (52.33%) vs.38 cases (37.25%)), pleural effusion (23 cases (26.74%) vs. 10 cases (9.80%)), and severe adenovirus pneumonia (7 cases (8.14%) vs. 2 cases (1.96%)) with χ²=5.11, 4.44, 11.16, 9.19, 4.30, 9.25, 3.91 and P=0.024, 0.035, 0.001, 0.002, 0.038, 0.002, 0.048, respectively, and also in length of hospital stay (11 (8, 15) vs. 7 (5, 13) d, Z=3.73, P<0.001). Conclusions: HAdV-3 and 7 were the predominate types of HAdV infection in hospitalized children with acute respiratory tract infection in Beijing. Compared with HAdV-3 infection, HAdV-7 infection caused more obvious inflammatory reaction, more severe pulmonary symptoms, longer length of hospital stay, suggesting the clinical necessity of further typing of HAdVs.

Ankle-Brachial Index and Subsequent Risk of Severe Ischemic Leg Outcomes: The ARIC Study

Background Ankle-brachial index (ABI) is used to identify lower-extremity peripheral artery disease (PAD). However, its association with severe ischemic leg outcomes (eg, amputation) has not been investigated in the general population. Methods and Results Among 13 735 ARIC (Atherosclerosis Risk in Communities) study participants without clinical manifestations of PAD (mean age, 54 [SD, 5.8] years; 44.4% men; and 73.6% White) at baseline (1987-1989), we quantified the prospective association between ABI and subsequent severe ischemic leg outcomes, critical limb ischemia (PAD with rest pain or tissue loss) and ischemic leg amputation (PAD requiring amputation) according to discharge diagnosis. Over a median follow-up of ≈28 years, there were 221 and 129 events of critical limb ischemia and ischemic leg amputation, respectively. After adjusting for demographics, ABI ≤0.90 versus 1.11 to 1.20 had a ≈4-fold higher risk of critical limb ischemia and ischemic leg amputation (hazard ratios, 3.85 [95% CI, 2.09-7.11] and 4.39 [95% CI, 2.08-9.27]). The magnitude of the association was modestly attenuated after multivariable adjustment (hazard ratios, 2.44 [95% CI, 1.29-4.61] and 2.72 [95% CI, 1.25-5.91], respectively). ABI 0.91 to 1.00 and 1.01 to 1.10 were also associated with these severe leg outcomes, with hazard ratios ranging from 1.7 to 2.0 after accounting for potential clinical and demographic confounders. The associations were largely consistent across various subgroups. Conclusions In a middle-aged community-based cohort, lower ABI was independently and robustly associated with increased risk of severe ischemic leg outcomes. Our results further support ABI ≤0.90 as a threshold diagnosing PAD and also suggest the importance of recognizing the prognostic value of ABI 0.91 to 1.10 for limb prognosis.

Ankle-brachial index and subsequent risk of incident and recurrent cardiovascular events in older adults: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

The ankle-brachial index (ABI) is a diagnostic test for screening and detecting peripheral artery disease (PAD), as well as a risk enhancer in the AHA/ACC guidelines on the primary prevention of atherosclerotic cardiovascular disease (ASCVD). However, our understanding of the association between ABI and cardiovascular risk in contemporary older populations is limited. Additionally, the prognostic value of ABI among individuals with prior ASCVD is not well understood.

METHODS

Among 5,003 older adults at ARIC visit 5 (2011-2013) (4,160 without prior ASCVD [median age 74 years, 38% male], and 843 with ASCVD [median age 76 years, 65% male]), we quantified the association between ABI and the risk of heart failure (HF), and composite coronary heart disease and stroke (CHD/stroke) using multivariable Cox regression models.

RESULTS

Over a median follow-up of 5.5 years, we observed 400 CHD/stroke events and 338 HF cases (242 and 199 cases in those without prior ASCVD, respectively). In participants without a history of ASCVD, a low ABI ≤0.9 (relative to ABI 1.11-1.20) was associated with both CHD/stroke and HF (adjusted hazard ratios 2.40 [95% CI: 1.55-3.71] and 2.23 [1.40-3.56], respectively). In those with prior ASCVD, low ABI was not significantly associated with CHD/stroke, but was with HF (7.12 [2.47-20.50]). The ABI categories of 0.9-1.2 and > 1.3 were also independently associated with increased HF risk. Beyond traditional risk factors, ABI significantly improved the risk discrimination of CHD/stroke in those without ASCVD and HF, regardless of baseline ASCVD.

CONCLUSIONS

Low ABI was associated with CHD/stroke in those without prior ASCVD and higher risk of HF regardless of baseline ASCVD status. These results support ABI as a risk enhancer for guiding primary cardiovascular prevention and suggest its potential value in HF risk assessment for older adults.

Cardiovascular and All-Cause Mortality Risk by Coronary Artery Calcium Scores and Percentiles Among Older Adult Males and Females

BACKGROUND

Coronary calcium is a marker of coronary atherosclerosis and established predictor of cardiovascular risk in general populations; however, there are limited studies examining its prognostic value among older adults (≥75 years) and even less regarding its utility in older males compared with females. Accordingly, we sought to examine the prognostic significance of both absolute and percentile coronary calcium scores among older adults.

METHODS

The multicenter Coronary Artery Calcium Consortium consists of 66,636 asymptomatic patients without cardiovascular disease. Participants ages ≥75 were included in this study and stratified by sex. Multivariable Cox regression models were constructed to assess cardiovascular and all-cause mortality risk by Agatston coronary calcium scores and percentiles.

RESULTS

Among 2,474 asymptomatic patients (mean age 79 years, 10.4-year follow-up), prevalence of coronary artery calcium was 92%. For both sexes, but in females more so than males, higher coronary calcium score and percentiles were associated with increased cardiovascular and all-cause mortality risk. Those at the lowest coronary calcium categories (0-9 and <25 percentile) had significantly lower risk of cardiovascular and all-cause mortality relative to the rest of the population. Multivariable analyses of traditional cardiovascular risk factors and coronary artery calcium variables revealed that age and coronary calcium were the strongest independent predictors for adverse outcomes.

CONCLUSIONS

Both coronary artery calcium scores and percentiles are strongly predictive of cardiovascular and all-cause mortality among older adults, with greater risk-stratification among females than males. Both low coronary artery calcium scores 0-9 and <25th percentile define relatively low risk older adults.

Increase in arterial stiffness measures after bariatric surgery

BACKGROUND AND AIMS

The relationship between obesity and arterial stiffness is complex, with a potential interaction by age (inverse association at younger age and positive at older age) and conflicting reports on the effect of lifestyle-based weight loss on arterial stiffness. Little is understood about post-bariatric surgery changes in arterial stiffness. This study aimed to examine post-bariatric surgery changes in arterial stiffness and identify factors associated with greater changes in arterial stiffness.

METHODS

In 72 patients (mean age 44.5 years, 72.2% female), we evaluated two arterial stiffness measures, cardio-ankle vascular index (CAVI) and heart-ankle pulse wave velocity (haPWV), one month prior to and 6 months after bariatric surgery. Another follow-up visit was conducted 12 months after bariatric surgery in a subset of 58 participants.

RESULTS

Six months after bariatric surgery, an evident decrease was seen in body mass index, heart rate, and systolic blood pressure. In contrast, both CAVI and haPWV significantly increased at 6 months (+0.64 [0.42, 0.87] and +0.24 [0.04, 0.44] m/s, respectively). Among 58 patients with relevant data, CAVI and haPWV remained elevated 12 months after bariatric surgery (+0.80 [0.53, 1.07] and +0.40 [0.17, 0.62] m/s, respectively). Being non-diabetic and having larger decreases in post-surgery heart rate were independently associated with greater increases in post-surgical CAVI.

CONCLUSIONS

Arterial stiffness measures, CAVI and haPWV, were elevated after bariatric surgery despite other favorable cardiometabolic changes. Further studies are necessary to elucidate the underlying mechanism and prognostic implications of this elevation in arterial stiffness measures after bariatric surgery.

Association between coronary artery calcium and cardiovascular disease as a supporting cause in cancer: The CAC consortium

BACKGROUND

Identifying cancer patients at high risk of CVD is important for targeting CVD prevention strategies and evaluating chemotherapy options in the context of cardiotoxicity. Coronary artery calcium (CAC), a strong marker of coronary atherosclerosis, is used clinically to enhance risk assessment, yet the value of CAC for assessing risk of CVD complications in cancer is poorly understood.

OBJECTIVE

In cases of cancer mortality, to determine the value of CAC for predicting risk of CVD as a supporting cause of death.

METHODS

The CAC Consortium is a multi-center cohort of 66,636 asymptomatic adults without CVD who underwent CAC scanning. During a follow-up of 12.5 years, 1129 patients died of cancer and were included in this analysis. The primary outcome was presence of CVD listed as a supporting cause of cancer mortality on official death certificates obtained from the National Death Index. Logistic regression models were used to assess the odds of CVD being listed as a supporting cause of death by CAC.

RESULTS

CVD was listed as a supporting cause of death in 306 (27%) cancer mortality cases. Baseline CAC was significantly higher in individuals with CVD-supported mortality. Odds ratios of having CVD-supported death increased by ASCVD risk score category [1.15 (0.81, 1.65) for 5-20% 10-year risk and 1.97 (1.36, 2.89) for ≥20% risk, in reference to <5% 10-year ASCVD risk] and CAC category [1.07 (0.73, 1.57) for CAC 1-99, 1.29 (0.87, 1.93) for CAC 100-399, and 2.14 (1.48, 3.09) for CAC ≥400 relative to CAC 0]. In the CAC ≥400 group, these associations remained significantly elevated after adjustment for traditional CVD risk factors [1.66 (1.08, 2.55)]. A sensitivity analysis using a more specific ASCVD-supported mortality outcome, defined as coronary heart disease, stroke, and peripheral artery disease, demonstrated that adjusted odds of ASCVD-supported cancer mortality were significantly elevated in the CAC ≥400 group relative to CAC 0 [3.09 (1.39, 7.38)].

CONCLUSIONS

In cancer mortality cases, high antecedent CAC predicted risk of having CVD as a supporting cause of death on official death certificates, independently of ASCVD risk score and CVD risk factors. CAC may be useful for identifying cancer patients at high CVD risk who might benefit from more intense preventive cardiovascular therapies.

Time Regularity of Morphology of Blood Pools

Abstract

Objective To provide reference indexes and theoretical basis for age estimation of blood pools by investigating the entire drying process and monitoring the change of morphology and mass. Methods Four 15 mL blood pool samples were prepared on the clean ceramic plate. The change of morphology and mass of blood pools in a closed dark environment with a temperature of （20.0±0.5） ℃ and a humidity of 35%-45% were dynamically observed from 0 h to 60 h. Images of the blood pools were recorded by digital camera. The area of blood pools was calculated by MATLAB R2014b, the length of cracks was measured by Image J and the statistical analysis was performed by SPSS 16.0. Results By summarizing and analyzing, the drying of blood pools was divided into five stages： coagulation （0-4.5 h）, gelation （>4.5-20.0 h）, gel-solid mixing （>20.0-37.0 h）, solid （>37.0-40.0 h） and final desiccation （>40.0-45.0 h）. From 0 to 45 h, the mass of the blood pools decreased linearly with time, and the decrease was not obvious from 45.0 to 60.0 h. The standardized mass （y₂） showed strong correlation with the time （x） y₂=0.018 2 x+0.271 4（R²=0.967 9）. The area change rate of blood pools, the distance that the edge of blood pools moved, the average length of radical cracks had little correlation with the time that passed. Conclusion The overall morphological characteristics of blood pools show a certain regularity with the time and the standardized indexes established provide a reference for the age estimation of blood pools.

[The mechanism study of ouabain in inhibiting the growth of hepatocellular carcinoma cells by inhibiting the laser kinase signaling pathway]

Objective: To investigate the effect of Na(+)/K(+)-ATPase inhibitor ouabain on the proliferation and division of liver cancer HepG2 cells, and to explore the anticancer mechanism. Methods: HepG2 cells were exposed with different concentrations of ouabain (0.1, 1, 10 μmol/L) for 24 h, the proliferation ability was appraised using CCK-8, and the HepG2 cells was as a control group. The status of chromosome separation was detected with cell immunofluorescence (ICC) coupled to confocal microscope. The expression levels of AURKA, mTOR, p-mTOR, ERK and p-ERK protein were analyzed using western blot. Results: After treating with 0.1, 1 and 10 μmol/L of ouabain for 24 h, the inhibitory rate of cells were (23.5±4.57)%, (49.80±5.32)%, and (72.10±5.62)%, respectively. Ouabain could significantly inhibit the proliferation of HepG2, and presented in a dose-dependent manner(F=32.8, P<0.05). The ICC results showed that the chromosome separation disorders occurred in HepG2 cells treated with 1 μmol/L for 24 h, and the spindle diameter of HepG2 cells with ouabain treatment was decreased significantly compared with the control group(t=9.58, P<0.05). The results of western blot showed that the expression levels of AURKA, p-mTOR and p-ERK expressions in HepG2 cells treated with 1 μmol/L of ouabain were significantly decreased compared with the control group(F=16.26, 8.32, 33.59, P<0.05). Ouabain inhibited the growth of hepatocellular carcinoma cells in nude mice(F=370.20, P<0.05). Conclusion: Ouabain can induce chromosome division disorder and inhibit the proliferation in liver cancer HepG2 cells by inhibiting AURKA signaling pathway.

Predicting self-reported depression after the onset of multiple sclerosis using genetic and non-genetic factors

BACKGROUND

Persons with multiple sclerosis (PwMS) are disproportionately burdened by depression compared to the general population. While several factors associated with depression and depression severity in PwMS have been identified, a prediction model for depression risk has not been developed. In addition, it is unknown if depression-related genetic variants, including Apolipoprotein E (APOE), would be informative for predicting depression in PwMS.

OBJECTIVE

To develop a depression prediction model for PwMS who did not have a history of depression prior MS onset.

METHODS

The study population included 917 non-Hispanic white PwMS. An optimized multivariable Cox proportional hazards model for time to depression was generated using non-genetic variables, to which APOE and a depression-related genetic risk score were included.

RESULTS

Having a mother who had a history of depression, having obstructive pulmonary disease, obesity and other physical disorders at MS onset, and affect-related symptoms at MS onset predicted depression risk (hazards ratios (HRs): 1.6-2.3). Genetic variables improved the prediction model's performance. APOE ε4/ε4 and ε2/x conferred increased (HR = 2.5, p = 0.026) and decreased (HR = 0.65, p = 0.046) depression risk, respectively.

CONCLUSION

We present a prediction model aligned with The Precision Medicine Initiative, which integrates genetic and non-genetic predictors to inform depression risk stratification after MS onset.

[Nutritional status and energy metabolism characteristics in patients with nonalcoholic fatty liver disease]

Objective: To study the nutritional status and energy metabolic characteristics of patients with nonalcoholic fatty liver disease (NAFLD), and to provide evidence for clinical evaluation and intervention. Methods: A total of 359 NAFLD patients diagnosed on ultrasound from June 2015 to March 2017 were selected as study subjects and divided into mild, moderate to severe fatty liver disease group and 50 healthy subjects as control group. The changes of ICW, ECW, body fat, skeletal muscle, protein and visceral fat area (VFA) of patients and controls were analyzed by using body composition analyzer. The energy metabolism index was measured by the oxidation rate of resting energy expenditure(REE), respiratory quotient (RQ), and the oxidation rates of the three nutrients (CHO %, FAT %, and PRO %). According to different types of data, non-parametric tests like Kruskal-Wallis or χ(2) were used for this analysis. Results: Compared with the mild fatty liver group and the control group, the moderate and severe fatty liver group the BMI, waist circumference, waist-hip ratio were significantly elevated (P-value < 0.001), and their serum alanine aminotransferase, triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein, FBS levels were significantly increased (P value < 0.05). The Body composition analysis showed that there was no significant difference in skeletal muscle content between the three groups (P = 0.067). The ICW, ECW, protein, body fat content of moderate and severe fatty liver group were significantly higher than those of mild fatty liver group and control group (P < 0.01), but there was no significant difference between the mild fatty liver group and the control group. There was significant difference in the VFA between the three groups, while VFA in the moderate and severe fatty liver group was significantly increased. Metabolic results showed that the RQ of patients with moderate-severe fatty liver and mild fatty liver were 0.72 ± 0.08 and 0.78 ± 0.06, respectively, which were lower than those of the control group (0.80 ± 0.02), P = 0.004. Resting energy expenditure (REE) was not significantly different between moderate and severe fatty liver group and mild fatty liver group (P = 0.207), but both were significantly higher than those of the control group (P < 0.001). The percentages of CHO, FAT and PRO in moderate and severe fatty liver group were 19.49% ± 9.71%, 66.23% ± 12.54% and 14.22% ± 6.11% respectively. Compared with the control group, CHO % decreased, and FAT % increased. Conclusion: NAFLD patients have different extent of nutritional imbalance and energy metabolism disorders, the use of Body Composition analyzer and metabolic cart can comprehensively assess and monitor NAFLD patient's nutrition and energy metabolism status, to provide a basis for clinical intervention.

[Association of PD-1, TIM-3 and TREM-1 single nucleotide polymorphisms with pulmonary tuberculosis susceptibility]

Objective: To investigate the association of programmed cell death 1(PD-1), T cell immunoglobulin mucin 3 (TIM-3) and triggering receptor expressed on myeloid cells-1 (TREM-1) genes polymorphisms with pulmonary tuberculosis susceptibility. Methods: In this case-control study, peripheral venous blood of 100 pulmonary tuberculosis patients (pulmonary tuberculosis group) in the Jintan People's Hospital of Changzhou and of community physical examination volunteers (health control group) was collected from Mar 2015 to Sep 2016. A total of 66 single nucleotide polymorphisms (SNP) in PD-1, TIM-3 and TREM1 sequences were selected and SNP genotype and allele frequency were analyzed using the next-generation sequencing technology. Association of these SNP with pulmonary tuberculosis susceptibility was investigated using linkage disequilibrium (LD) analysis and genetic models. Results: Among these 66 SNP, 24 SNP with Hardy-Weinberg equilibrium P (HWE-P) value <0.001 or minimum allele frequency (MAF) <0.05 were kicked out. The remaining 42 SNP were analyzed with LD analysis and genetic models. There was no significant difference in genotype frequencies between pulmonary tuberculosis group and health control group (all P>0.05). Five SNP (rs41435650, rs28539662, rs13023138, rs75565781, rs36084323) in PD-1 were identified in a significant haplotype (TACGC) between pulmonary tuberculosis group and health control group (P=0.014). Among these haplotypes, strong LD was observed between rs28539662 and rs75565781 (r(2)=0.871), as well as rs36084323 (r(2)=0.864). Rs75565781 showed highest correlation with rs36084323 (r(2)=0.966). Conclusion: These SNP in PD-1, TIM-3 and TREM-1 genes are not associated with the susceptibility of pulmonary tuberculosis.

Spirometra erinaceieuropaei severely infect frogs and snakes from food markets in Guangdong, China: implications a highly risk for zoonotic sparganosis

Sparganosis is a parasitic disease caused by plerocercoid larvae of the genus Spirometra. In China, the main source of sparganosis is from Guangdong, 16.1% of the country's human sparganosis cases occur in this province. Frequent international trade of amphibians and reptiles in Guangdong may introduce new species of Spirometra into the local market. In this study, a large-scale, high-intensity sampling survey was conducted to find out the causative species and epidemic situation of Sparganosis in Guangdong. The prevalence of sparganum infection in five species of frogs (Boulengerana guentheri, Fejervarya multistriata, Hoplobatrachus chinensis, Pelophylax nigromaculatus and Quasipaa spinosa) and nine species of snakes (Elaphe carinata, Lycodon rufozonatum, Hypsiscopus plumbea, Ptyas dhumnades, P. korros, P. mucosa, Naja atra, Sinonatrix annularis and Xenochrophis piscator) was investigated in Guangdong, Southern China from May 2014 to August 2015. The results showed that 9.8% (50/511) of the frogs and 40.8% (141/ 346) of snakes were found to be infected by plerocercoids (spargana). To identify the species of the collected spargana, a partial sequence of the mitochondrial cytochrome c oxidase subunit1 gene (cox1) was amplified and sequenced. Phylogenetic analysis identified all the spargana specimens as Spirometra erinaceieuropaei. Our study indicated that S. erinaceieuropaei, a highly pathogenic parasite, is the only causative agent of sparganosis in Guangdong, China. This study suggests that the large numbers of frogs and snakes in food markets in Guangdong may impact public health in China by transmitting S. erinaceieuropaei sparganum. Additional steps should be considered by the governments and public health agencies to prevent the risk of food-associated Spirometra infections in humans in China.

[Re-treatments of recurrence after pelvic floor repair surgery]

Objective: To analyze re-treatments of recurrence after the pelvic floor repair surgery. Methods: The protocol and the effect of re-treatments were investigated by reviewing and analyzing the clinical data of 81 recurrent patients (grade Ⅱ and above), who had received the pelvic floor repair surgery from January 2011 to January 2016. Pelvic organ prolapse quantitation system (POP-Q) and two questionnaires about quality of life [pelvic floor distress inventory-short form 20 (PFDI-20) and pelvic floor impact questionnaire short form (PFIQ-7)] were used to evaluate objective and subjective efficacy, respectively. Results: Among 81 recurrent patients who were followed up for a median of 35 months (10- 69 months), 78 cases (with prolapse up to grade Ⅲ or Ⅳ) were treated by surgical operation with both objective cure rate and subjective satisfaction being 100% (78/78); 3 cases (with grade Ⅱ prolapse) were treated by pelvic floor electrical stimulation biofeedback, and 1 case among the three cases had the vaginal foreign body sensation, the subjective satisfaction was 2/3. The methods of surgical operation for the 78 recurrent patients included: total pelvic floor reconstructive surgery (55 cases; 3 of which involve trachelectomy), anterior pelvic reconstructive surgery (2 cases), posterior pelvic reconstructive surgery (3 cases), Y-mesh sacral colpopexy (2 cases), colpocleisis (11 cases), vaginal hysterectomy combined posterior fornix forming (3 cases), and vaginal hysterectomy combined posterior pelvic reconstructive surgery(2 cases). Conclusion: The extent of recurrence, the recurrent site and complications must be carefully considered and evaluated for re-treatments of recurrence after pelvic floor repair surgery, and then an appropriately individualized re-treatment protocol could be designed for each of the patients.

[Hospital costs and related influencing factors in patients with acute poisoning]

Objective: To investigate the hospital costs and related influencing factors in patients with acute poisoning. Methods: A retrospective analysis was performed for the general status and hospital costs of 373 patients with acute poisoning who were admitted to The Second Affiliated Hospital of Wenzhou Medical College from January 2009 to March 2015. The questionnaires were completed, the data were entered into Excel forms, and SPSS 18.0 was used to perform statistical analysis. Results: Among the 373 patients, 44.8% committed suicide and 31.1% were poisoned by accidental contact; 42.6% were poisoned by pesticides, and 32.7% were poisoned by drugs. After treatment, 64.1% achieved improvements, whereas 1.3% died. The highest hospital cost reached 62 710.26 RMB, and the lowest was 64.64 RMB (median 4 328 RMB) . The patients with an older age and a longer length of hospital stay tended to have higher hospital costs; the patients who underwent catharsis, mechanical ventilation, and blood purification and were admitted to the intensive care unit had relatively high hospital costs. Conclusion: The patients with acute poisoning have high hospital costs. Poisoning caused by pesticides and drugs should be prevented and treated with priority, so as to reduce the heavy economic burden caused by acute poisoning.

Fabrication method of high-quality Ge nanocrystals on patterned Si substrates by local melting point control

The local melting point of a Ge thin film can be controlled by a hole-array pattern on the host Si substrate due to the variations in the stress distribution and the surface morphology induced by the pattern. A simple annealing process is developed from this effect to produce Ge NCs with a single-domain-crystal size over 20 nm, confirmed by transmission electron microscopy and Raman spectroscopy, from an electron-gun-evaporated Ge thin film on the patterned Si substrate. The effect of the dimensions of the hole array is also investigated. Photoluminescence observed around 1157 nm from some of the samples shows the possibility of improving the infrared emission capability by this proposed method.

Lipopolysaccharide-induced dental pulp cell apoptosis and the expression of Bax and Bcl-2 in vitro

Lipopolysaccharide exerts many effects on many cell lines, including cytokine secretion, and cell apoptosis and necrosis. We investigated the in vitro effects of lipopolysaccharide on apoptosis of cultured human dental pulp cells and the expression of Bcl-2 and Bax. Dental pulp cells showed morphologies typical of apoptosis after exposure to lipopolysaccharide. Flow cytometry showed that the rate of apoptosis of human dental pulp cells increased with increasing lipopolysaccharide concentration. Compared with controls, lipopolysaccharide promoted pulp cell apoptosis (P < 0.05) from 0.1 to 100 μg/mL but not at 0.01 μg/mL. Cell apoptosis was statistically higher after exposure to lipopolysaccharide for 3 days compared with 1 day, but no difference was observed between 3 and 5 days. Immunohistochemistry showed that expression of Bax and Bcl-2 was enhanced by lipopolysaccharide at high concentrations, but no evident expression was observed at low concentrations (0.01 and 0.1 μg/mL) or in the control groups. In conclusion, lipopolysaccharide induced dental pulp cell apoptosis in a dose-dependent manner, but apoptosis did not increase with treatment duration. The expression of the apoptosis regulatory proteins Bax and Bcl-2 was also up-regulated in pulp cells after exposure to a high concentration of lipopolysaccharide.

Magnetic plasmon modes in periodic chains of nanosandwiches

The magnetic plasmon (MP) modes in periodic chains of metallic trilayer nanostructures (nanosandwich) have been investigated numerically in optical frequency region. By employing the Fourier Transformation (FT) method, the MP modes excited in these chains can be observed directly.We have also used different exciting sources to excite the MP modes in the chain so that we can get clearer physics picture and richer information of the nanosandwich chain. For their long propagating lengths, the nanosandwich chains can well work as subwavelength waveguides to transport electromagnetic field. And one can easily tune the working frequencies and band width of the MP modes by changing the parameters of these chains.

Surface-plasmon-induced optical magnetic response in perforated trilayer metamaterial

Surface plasmon excitations and the associated optical transmission properties in perforated metal/dielectric/metal trilayer structures are numerically investigated. Pronounced magnetic modes are observed in the antisymmetric and asymmetric modes of surface plasmon polaritons (SPPs). The influence of substrates on the magnetic response is studied in detail. Quite different from the conventional LC-circuit resonance, these magnetic excitations arise from the nonlocalized SPPs in the perforated layered structure, which may considerably enrich the electromagnetic properties of such metamaterials, especially the artificial magnetism at optical frequency.

Metamaterial of rod pairs standing on gold plate and its negative refraction property in the far-infrared frequency regime

A new kind of metamaterial, an array of periodic gold rod pairs standing on gold substrate, is introduced in this paper. A commercial electromagnetic mode solver, the High-Frequency Structure Simulator, is employed to explore the propagation property of electromagnetic waves in this system. When an S -polarized electromagnetic (EM) wave propagates along the substrate surface, strong magnetic resonance is produced in the far-infrared regime. Based on the simulated S parameters, effective refraction index is retrieved and negative value is obtained over the wavelength range from 49.2 microm to 66.7 microm. A wedge made of this metamaterial with an inclined angle 26.6 degrees is designed. An observable negative refraction behavior of EM wave is attained in this structure at wavelength 61.2 microm. The refractive index is calculated by Snell's law and it is consistent with the retrieved results quite well. This provides direct evidence for the negative refraction property.

Coupling effect of magnetic polariton in perforated metal/dielectric layered metamaterials and its influence on negative refraction transmission

The optical propagation properties and magnetic polariton behaviors in perforated metal/dielectric layered structures are numerically investigated at near-IR region. A developed three-metal-layer (TML) structure is specially inspected as a simple case. Strong coupling effect of magnetic polariton is discovered in this system, which explains why TML structure reveals better negative-refraction property than the reported double-metal-layer (DML) structure. A clear LC-circuit model is presented to describe the physical mechanism of this coupling effect of magnetic polaritons. Detailed results show that the thickness of metal layer influences the transmission greatly and an optimum value is found.

Analysis of luteolin in Elsholtzia blanda Benth. by RP-HPLC

The total luteolin content in Elsholtzia blanda Benth. extracts (EBBE) was determined using reversed phase HPLC. C18 was used as the packing material and 0.01 M phosphate buffer (pH 2)-tetrahydrofuran-isopropanol (70:30:5) as the mobile phase with detection wavelength 360 nm. The recovery of the method was 96.4%-101.8%, and the assay was linear at concentrations from 5 to 200 microg/ml (r = 0.9999). The results indicated that the content of luteolin in EBBE extracted under different conditions varied significantly. This method can be used to optimize the extraction procedure and determine the content of luteolin in Elsholtzia blanda Benth. extracts.

Disposition of quercetin and kaempferol in human following an oral administration of Ginkgo biloba extract tablets

Ten adult volunteers with an average age 28 years were given a single oral dose of six tablets of Ginkgo biloba extract. Quercetin and kaempferol in different period of human urine were determined by using RP-HPLC. The results showed the elimination rate constant k and the absorption rate constant ka of quercetin were slightly more than that of kaempferol; and the absorption half-life (t(1/2a)), the elimination half-life (t(1/2)) and t(max) of quercetin were less than that of kaempferol, the differences were, however, not statistically significant. The mean values of ka were 0.61 h(-1) and 0.55 h(-1), t(1/2a) 1.51 h and 1.56 h, k 0.37 h(-1) and 0.30 h(-1), t(1/2) 2.17 h and 2.76 h, T(max) 2.30 h and 2.68 h for quercetin and kaempferol, respectively, which mean absorption and elimination of quercetin and kaempferol are 0.17% and 0.22%, respectively. Quercetin and kaempferol are excreted in the human urine mainly as glucuronides.

Determination of quercetin and kaempferol in human urine after orally administrated tablet of ginkgo biloba extract by HPLC

A sensitive, simple and accurate method was developed for determination of quercetin and kaempferol in human urine by reversed phase high performance liquid chromatography. The urine samples were analyzed on C18 column. Quercetin and kaempferol were analyzed simultaneously with good separation. UV detector was set at 380 nm. There was a linear relationship between chromatographic area of analytes and concentration of analytes over the concentration range 1.638-81.90 and 1.872-93.60 ng/ml for quercetin and kaempferol, respectively. The recovery of the assay was 99.7+/-6.2 and 97.4+/-7.2% for quercetin and kaempferol, respectively. The within-day and between-day coefficients of variation were less than 9.7 and 16.5% (RSD), respectively. The limit of detection was 1.0 ng/ml for quercetin and 1.1 ng/ml for kaempferol. The limit of quantitation was 1.61+/-0.11 ng/ml (n=5) for quercetin and 1.85+/-0.11 ng/ml (n=5) for kaempferol. The method developed has been applied to determine quercetin and kaempferol after orally administrated tablet of Ginkgo biloba extract in human urine.

Experimental study of the protection of ischemic preconditioning to spinal cord ischemia

BACKGROUND

Since the advent of ischemic preconditioning in myocardium, more and more attention has been paid to ischemic preconditioning in the central nervous system (CNS). This study was designed to evaluate the protective effect of ischemic preconditioning on spinal cord ischemia.

METHODS

Interventional neuroradiological techniques were used to induce spinal cord ischemia in a rabbit model. Hydrogen electrode technique was used to determine the regional blood flow of the spinal cord. Catecholamines and their metabolites were measured by high performance liquid chromatography (HPLA). Spinal cord evoked potentials were recorded to show spinal cord neurofunction.

RESULTS

After 5 minutes ischemic preconditioning with 20 minutes reperfusion, the regional spinal cord blood flow (rSCBF) was increased, as may be seen by the slight increase of catecholamine, especially NE. This is in positive proportion to the cAMP and indicates the enhancement of the metabolic activities of the spinal cord. After 30 minutes of irreversible ischemia, the great increase in catecholamine caused vascular spasm, endotheliocyte fissure, multiple hemorrhagic suffusion, and necrosis, which would injure the spinal cord as a result. The slight increase of the rSCBF and the maintenance of the rSCBF after irreversible ischemia may enhance the protection of ischemic preconditioning to the spinal cord neurofunction, which was proved by spinal cord evoked potentials (SCEPs).

CONCLUSIONS

Our study showed that 5 minutes of ischemic preconditioning can increase the rSCBF, enhance the tolerance of the spinal cord to irreversible ischemia, and protect the neurofunction of the spinal cord. The biological mechanism of the protective effect of ischemic preconditioning to spinal cord ischemia should be further studied.

Preoperative concurrent chemotherapy and radiotherapy in rectal cancer patients

The management of rectal cancer has changed significantly in recent years. The key end-point is no longer survival but rather preservation of sphincter function with improved quality of life. Preoperative radiation can not only render a low-lying rectal tumor amenable to sphincter-preserving surgery but has also been reported to give better local control and lower toxicity than postoperative radiotherapy. From October 1991 through July 1996, 46 patients with local advanced or low-lying rectal cancer were treated with preoperative high-dose radiotherapy and concurrent chemotherapy. All patients underwent pelvic radiotherapy with 5,000 to 5,400 cGy in 25 to 27 fractions. Chemotherapy was given concomitantly and consisted of two courses of 5-fluorouracil (5-FU) at 1,000 mg/m2 for 4 days in week 1 and week 5 plus mitomycin C 10 mg/m2 single bolus on day 1 of week 1. In 30 patients, postoperative adjuvant chemotherapy with 5-FU and levamisole weekly was also given, for a total of 12 months. The most common acute toxicity was grade 1 to 2 diarrhea and tenesmus during radiation or soon afterward. Only five of the 46 patients experienced symptomatic grade 3 acute toxicity. Forty-two patients underwent subsequent surgery 6 to 8 weeks after concurrent chemoradiotherapy. Pathologic examination disclosed complete tumor regression in eight patients and microscopic residual disease in 13 patients after preoperative chemoradiation. Of the 42 patients who completed the intended treatments, only one had local recurrence. The sphincter was preserved in 21 of the 26 patients in whom the tumor was located within 5 cm above the anal verge. Twelve of the 16 evaluable patients had good to excellent sphincter function. The 2-year overall survival rate was 93% and the disease-free survival was 81%. Our findings indicate that preoperative concurrent chemoradiotherapy not only allows low-lying rectal tumors to be resected while preserving sphincter function but also results in good local control and acceptable toxicity.

Isolated vertiginous dysequilibrium due to bilateral caudal cerebellar infarction

We present a 74-year-old woman who developed a sudden onset of vertigo, vomiting, and axial retropulsion without limb ataxia. A clinical diagnosis of acute peripheral labyrinthine lesion was made initially. However, magnetic resonance imaging demonstrated a small infarct area involving the caudal part of the cerebellar vermis and medial cerebellar hemispheres on both sides. We emphasize that a cautious attitude should be taken in managing patients with isolated vestibular dysfunction, especially in aged person or those associated with stroke risk factor.

[The diagnostic value of anti-BB-antibody estimation in sarcoidosis]

Anti-BB-antibody estimation was carried out in 100 cases of sarcoidosis, 40 cases of suspected sarcoidosis, 45 cases of pulmonary tuberculosis, 39 cases of pulmonary infections, 17 cases of bronchogenic carcinoma and 60 healthy persons as control. The result showed, that the patients suffering from sarcoidosis had the highest positive rate of anti-BB-antibody levels, whereas the positive rate of anti-BB-antibody levels in patients suffering from suspected sarcoidosis, pulmonary infections and tuberculosis was lower than that in patients suffering from sarcoidosis. Patients suffering from bronchogenic carcinoma and healthy controls had the lowest levels of anti-BB-antibody. It was suggested that sarcoidosis may have some relationship with infection.

[Borrelia burgdorferi may be the causal agent of sarcoidosis]

Serum antibody to Borrelia burgdorferi was measured in 33 patients with sarcoidosis who were confirmed clinically and pathologically. The results showed that 81.8% of the patients were positive. In addition, a strain of Borrelia burgdorferi was isolated from a patient's blood. Fourteen patients received ceftriaxone 2 g per day and/or penicillin 12 million per day and a patient received lincomycin 1.2 g per day. The antibody titer of the patients turned to normal level, their SACE turned to normal range, and chest X-ray findings were markedly improved in 3 cases after the treatment. According to the facts mentioned above, we consider that Borrelia burgdorferi may be the causal agent of sarcoidosis and sarcoidosis might be a special type of Lyme disease.

Borrelia burgdorferi infection may be the cause of sarcoidosis

Serum antibody to Borrelia burgdorferi was measured in 33 patients with sarcoidosis which was confirmed clinically and pathologically. The results showed that 81.8% of the patients were positive for anti-B. burgdorferi antibody. In addition, a strain of B. burgdorferi was isolated from a patient's blood. Fifteen patients received ceftriaxone 2g per day or penicillin 12 million U per day. The antibody titers of the patients decreased to nearly normal levels rapidly. Serum angiotensin converting enzyme (SACE) turned to normal range after the treatment. According to the findings mentioned above, we consider that B. burgdorferi infection may be the cause of sarcoidosis and sarcoidosis might be a specific type of Lyme disease.

Types of dementia in Taiwan--a prospective study

We prospectively investigated 100 consecutive inpatients with suspected dementia to evaluate the relative frequency of various types of dementia in a general hospital of Taiwan. Dementia was confirmed in 86 cases (86%) according to the dementia criteria of the third revised edition of the Diagnostic and Statistical Manual of Mental Disorders and Clinical Dementia Rating Scale (greater than or equal to 1). In contrast to the western developed countries, vascular dementia (VD) (35%) was the leading type of dementia, followed by Alzheimer's disease (AD) (27%), mixed VD and AD (MIX) (14%), and other degenerative diseases (10%). Ten cases (11.6%) of potentially treatable dementia were identified and 8 of 10 had good improvement after appropriate treatment. There were significant age differences among patients with MIX, AD and VD (p less than 0.01). Those with MIX were the oldest (72.12 +/- 9.4) followed by AD (69.70 +/- 8.52) and VD (64.81 +/- 9.12). Males were slightly predominant in this series (male:female = 50:36). A comprehensive clinical investigation including laboratory tests, electroencephalography and CT are necessary in the assessment of demented patients in order to make correct etiological diagnoses which lead to appropriate treatment or management of this terrifying syndrome.

Congenital dacryocele. A collaborative review

Fifty-four cases of congenital dacryocele from several medical centers were reviewed retrospectively. There was strong female preponderance (73%) and unilateral involvement (88%). Lacrimal sac contents could be expressed by local massage through the puncta in 21% of cases. Probing and irrigation were done under general (27.8%) or local (55.6%) anesthesia, while in other cases (16.7%), the cyst resolved before intervention. Recurrence of the dacryocele occurred in 10 patients (22%) after probing. Nasal cysts were visualized in six cases. Marsupialization of nasal cysts was necessary in four cases. In one center, after conservative therapy, 80% of cysts resolved spontaneously and 20% developed dacryocystitis. Surgical intervention is indicated in cases of dacryocystitis, cellulitis, breathing difficulty from large nasal cysts, recurrent dacryocele, and lack of its resolution after a short trial of digital massage.