A Single-Institution Review of the Use of Radiation in the Adjuvant and Definitive Management of Keloids

AIMS

Many individuals suffer from keloids that are refractory to standard treatment modalities, including surgical excision alone. Radiation therapy can be used to reduce the risk of recurrent keloids post-operatively, as well as be used as primary treatment for keloids not amenable to surgical resection. The purpose of this study was to review our institutional experience of radiation therapy for keloid management.

MATERIALS AND METHODS

A retrospective review of patients treated with radiation therapy for keloids between 2014 and 2020 at our institution was performed.

RESULTS

A total of 70 keloids in 41 patients were treated. For the 55 keloids treated with post-operative radiation therapy (16Gy delivered in 2 fractions), 82.5% (33/40) of evaluable lesions did not recur. Among the 15 keloids treated with definitive radiation therapy (24Gy delivered in 3 fractions), 78.6% (11/14) of evaluable keloids showed complete flattening, and 14.3% (2/14) had partial flattening. Both acute and late toxicities were mild, with only a single instance of grade 3 toxicity (dermatitis).

CONCLUSION

Our study confirms that radiation therapy has a role in reducing the risk of keloid recurrence post-operatively, and plays an important role in the definitive management of unresectable keloids.

Prognostic Value of Tumor Volume Reduction during Radiotherapy in Patients with Locally Advanced Cervical Cancer in Different Risk Groups

PURPOSE/OBJECTIVE(S)

To evaluate the risk factors of patients with locally advanced cervical cancer (LACC) undergoing radical radiotherapy (with or without concurrent chemotherapy) and to assess the prognostic value of tumor volume regression (TVR) based on magnetic resonance imaging (MRI) in different risk groups.

MATERIALS/METHODS

A retrospective analysis was performed on 176 individuals diagnosed with stage IIA-IVA cervical cancer (CC) who underwent radical intensity-modulated radiotherapy in our center between January 2012 and December 2020. The tumor volume before radiotherapy (TVp) and before brachytherapy (TVmid) were evaluated based on three-dimensional MRI images, TVR = (TVp -TVmid)/TVp × 100%. Kaplan-Meier curves were used to assess patient's overall survival (OS) and progression-free survival (PFS). Prognostic factors were identified using Cox proportional hazards models.

RESULTS

For the entire cohort, patients with TVR ≥ 94% had better 5-year OS (82.7% vs 49.8%, p<0.001) and 5-year PFS (82.5% vs 51.1%, p<0.001) compared to TVR < 94%. Patients with TVR ≥ 94% were more likely to receive concurrent chemoradiotherapy (CCRT) than those with TVR < 94% (70.1% vs 40.5%, p<0.05). Among patients undergoing CCRT, those with a TVR ≥ 94% had a better prognosis than those with a TVR < 94%. However, among patients who received RT alone, those with TVR ≥ 94% had better PFS but no statistically significant difference in OS. Likewise, among patients with CYFRA21-1 < 7.7 ng/ml, patients with TVR ≥ 94% had a better prognosis. However, TVR was not a prognostic factor in patients with CYFRA21-1 ≥ 7.7 ng/ml. Both CYFRA21-1 (OS, PFS interaction, p<0.001) and FIGO stage (PFS interaction, p = 0.035) were found to significantly impact predictive effects of TVR.

CONCLUSION

In LACC patients with CRYFA21-1 < 7.7 ng/ml who received CCRT, TVR was an important prognostic factor. However, in patients with CRYFA21-1 ≥ 7.7 ng/ml who received RT alone, the prognostic value of TVR needs to be further explored.

Management and Outcomes of Hodgkin Lymphoma Patients Who Achieve Partial Metabolic Response on PET Scans Post-Chemotherapy

PURPOSE/OBJECTIVE(S)

Optimal management of patients with Hodgkin Lymphoma (HL) who do not achieve PET (positron emission tomography) complete metabolic response after primary systemic therapy is unclear. Options vary significantly and include radiation therapy (RT) to localized sites of PET avid disease, salvage chemotherapy followed by autologous stem-cell transplantation (ASCT), or observation with serial imaging. This multi-center study sought to investigate the management approaches and outcomes for HL patients who achieved partial metabolic response after primary systemic therapy.

MATERIALS/METHODS

In this retrospective study, patients diagnosed with HL were identified from the electronic medical records database of two large academic centers between January 2009 and September 2021. PET scan results following initial chemotherapy were reviewed and responses were categorized using International Working Group (IWG) criteria, with the initial staging imaging being used as the reference against which response was evaluated. We performed descriptive analysis of demographic and clinical characteristics of the population and Kaplan-Meier estimates were used to determine progression-free survival (PFS).

RESULTS

The charts of 1,093 HL patients were reviewed. A total of 765 patients had a post chemotherapy PET scan with 57 of those showing partial metabolic response. Among these 57 patients, 31 (54%) were male, the median age at diagnosis was 31 (range:18-74), and the median length of follow up was 1.6 years (average 2.9 years). Five percent stage I, 32% stage II, 23% stage III, and 40% stage IV. Typical initial chemotherapy included ABVD, ABVD switched to BEACOPP due to abnormal interim PET, and AVD with Brentuximab. Among all patients with metabolic partial response to chemotherapy, the 2-year PFS was 72.8% (95% CI = 60.9-87%). Thirty-three of these patients (58%) were treated with planned radiation therapy alone, and 2-year PFS was 80.7% (95% CI = 66.6-97.9%). For those who did not receive radiation as part of their treatment, progression rate was 38% at 2 years.

CONCLUSION

To our knowledge, this is the largest series of HL patients with partial metabolic response following primary chemotherapy. Our preliminary analysis showed that treatment with radiation was associated with good PFS at 2 years and many of those treated with radiation alone were cured.

Reduced prescription of TNF-inhibitors in chronic arthritis based on therapeutic drug monitoring: A randomized controlled trial

OBJECTIVE

Dosing of tumour necrosis factor-α inhibitors (TNFis) is not personalized causing interindividual variation in serum drug levels; however, dose optimization is not widely implemented. We hypothesized that some patients are overdosed; thus, drug prescription could be reduced by therapeutic drug monitoring (TDM).

METHOD

Independent of disease activity, 239 adults treated for rheumatoid arthritis (n = 99), psoriatic arthritis 15 (n = 48), or spondyloarthritis (n = 92) were recruited for a 48-week prospective, randomized open-label trial. Standard care alone or plus TDM was applied in chronic arthritis patients treated with infliximab (IFX), (n = 81), etanercept (ETN) (n = 79), or adalimumab (ADA) (n = 79). Serum TNFi trough levels assessed at inclusion and every 4 months determined patients within/outside predefined therapeutic intervals, supporting change in prescription or drug switch. The primary endpoint was reduced drug prescription.

RESULTS

Compared to standard care, TDM reduced prescribed IFX [-12% (95% confidence interval -20, -3); p = 0.001] and ETN (-15% (-29, 1); p = 0.01], and prolonged the interdosing intervals of ETN [+235% (38, 432); p = 0.02] and ADA [+28% (6, 51); p = 0.04]. Time to drug switch was accelerated (χ2 = 6.03, p = 0.01). No group differences in adverse events, disease activity, or self-reported outcomes were shown, indicating equally sustained remission.

CONCLUSIONS

TDM reduced prescription of IFX, ETN, and ADA and identified patients benefiting from accelerated drug switch, thereby minimizing treatment failure, risk of toxicity, and unnecessary adverse events.

[Application of indocyanine green fluorescence visualization in surgical resection of abdominal wall endometriosis]

Objective: To investigate the feasibility, effectiveness and safety of indocyanine green (ICG) navigation in the surgical resection of abdominal wall endometriosis (AWE). Methods: Seven women undergoing surgery for AWE in First Affiliated Hospital of Sun Yat-sen University (from July 1, 2021 to October 1, 2021) were collected. After exposure of the focus, ICG were used intravenously (0.25 mg/kg) as fluorescent dye for the intraoperative evaluation of AWE vascularization. Resection of the AWE was guided by direct visualization of the focus under standard laparoscopy with a near-infrared (NIR) camera head. Surgical margin around the AWE (3, 6, 9 and 12 point) and the margin under the focus were obtained for postoperative pathological examination of endometriosis. Time from injection to fluorescence visualization, the proportion of fluorescence visualization, time of fully resection of AWE, side effects related to the use of ICG, perioperative complications as well as the pathological result of the surgical margins were recorded. Results: ICG fluorescence of the AWE were seen in 5 patients (5/7). The mean time from injection to fluorescence visualization was (46.7±9.8) s. The mean time of fully resection of AWE was (16.4±7.0) minutes. There were no side effects related to the use of ICG. The rate of class-A wound healing was 7/7. All of the surgical margins were confirmed endometriosis-negative by postoperative pathological examination. Conclusion: ICG fluorescence visualization could conduct accurate resection of AWE, which is clinically safe and effective.

Maintenance treatment in advanced HER2-negative gastric cancer

Survival for patients with advanced gastric cancer (GC) remains poor. Systemic chemotherapy which has reached a plateau stays the standard first-line (1L) treatment for advanced human epidermal growth-factor receptor 2 (HER2)-negative GC. To maximize the benefit of 1L treatment, the concept of maintenance treatment is constantly being explored. In advanced HER2-negative GC, current clinical guidelines do not recommend a standard maintenance therapy strategy. In addition to the monotherapy maintenance with fluorouracil after 4-6 cycles of 1L chemotherapy, some agents that are active against novel targets have been evaluated in clinical trials for maintenance treatment. Whereas most of these trials do not reach their primary endpoints, they open new horizons for the 1L treatment of advanced HER2-negative GC. Therefore, we reviewed the clinical trials in the field of maintenance treatment in advanced HER2-negative GC and discussed some of the problems in clinical trials.

0919 Health Disparities in the Persistence of Childhood Insomnia Symptoms in the Transition to Adolescence: The Penn State Child Cohort

Introduction

A strong body of cross-sectional evidence indicates that social determinants of health (SDH), such as race, ethnicity, socioeconomic status, and sex/gender, are linked to sleep problems, including insomnia symptoms. Few studies have examined the longitudinal association between SDH and the persistence and remission of insomnia symptoms in the transition between childhood and adolescence, a critical period for sleep health.

Methods

The Penn State Child Cohort is a random, population-based sample of 700 children (5-12y at baseline), of whom 421 were followed up as adolescents (12-23y at follow-up). All subjects underwent polysomnography, clinical history, physical exam, and parent- and self-reported scales at baseline and follow-up. Childhood insomnia symptoms were defined as a parent- and/or self-report of difficulty falling and/or staying asleep. All subjects or their parents identified the subject’s sex, race, and ethnicity, and reported on socioeconomic status (SES) of the household.

Results

Females (32.7%) and racial/ethnic minorities (25.0%) were associated with a significantly lower remission rate as compared to males (53.3%) and non-Hispanic whites (48.3%), respectively. Non-Hispanic whites of low SES were associated with a significantly lower full remission rate (26.3%) as compared to non-Hispanic whites of higher SES (42.0%), while racial/ethnic minorities were associated with the lowest full remission rates regardless of whether they were of low (9.1%) or higher (11.1%) SES.

Conclusion

Our novel data indicate that gender-, racial/ethnic- and socioeconomic-related disparities in insomnia not only occur as early as childhood but are important determinants of insomnia’s chronic course throughout development.

Support

National Institutes of Health (R01HL136587, R01HL97165, R01HL63772, UL1TR000127)

0936 Cardiometabolic Disorders are Independently Associated with Excessive Daytime Sleepiness in Young Adults

Introduction

Cardiometabolic risk factors (CMR), including obesity, hypertension, diabetes and hypercholesterolemia, have been associated with sleep apnea and insufficient sleep, both of which can lead to excessive daytime sleepiness (EDS). We hypothesized that CMR are associated with EDS in young adults independent of sleep apnea, sleep duration and mental health disorders (MHD).

Methods

The Penn State Child Cohort is a population-based longitudinal sample of 700 children (8.7±1.7y), of whom 421 were followed-up 8.3 years later during adolescence (17.0±2.3y) and 425 another 7.0 years later during young adulthood (24.4±2.6y). Subjects underwent a 9-h in-lab polysomnography in childhood and adolescence and parent- or self-reported standardized surveys at all time points. Self-reports in young adulthood and in-lab measurements in childhood were used to ascertain CMR and sleep apnea. Parent-reports in childhood and self-reports in young adulthood were used to ascertain the presence of MHD and EDS. Logistic regression models adjusted for age, race, sex, snoring/observed apneas, insomnia symptoms, and sleep duration in young adulthood as well as mean arterial blood pressure, body mass index percentile and apnea/hypopnea index in childhood.

Results

CMR (OR=2.71, 95%CI=1.69-4.36) and MHD (OR=4.61, 95%CI=2.79-7.62) were associated with EDS in univariate models. After adjusting for covariates in childhood and young adulthood, CMR and MHD remained independently associated with EDS (OR=2.32, 95%CI=1.29-4.16 and OR=2.78, 95%CI=1.59-4.87, respectively).

Conclusion

EDS in young adults with CMR or MHD does not solely arise from sleep apnea, insufficient sleep or other sleep disturbances. EDS may be the result of central pathophysiologic mechanisms or the functional impairment associated with cardiovascular, metabolic and mental health disorders. These data further support that youth with these disorders should be screened for EDS and appropriately managed.

Support

National Institutes of Health (R01HL136587, R01HL97165, R01HL63772, UL1TR000127)

0920 Behavioral Profiles Associated with the Development of Insomnia Symptoms in Children with Known Mental Health Disorders

Introduction

Mental health disorders (MHD) are a known risk factor for the development of insomnia symptoms in youth. However, a number of children with MHD do not go on to develop insomnia symptoms later on in life. Little is known about possible childhood factors that exacerbate or mitigate the risk of developing adolescent insomnia symptoms (AIS) among children with MHD. The present study examined, in an at-risk group of children with MHD, the behavioral profiles associated with the development of AIS.

Methods

The Penn State Child Cohort is a random, population-based sample of 700 children (5-12y), of whom 421 were followed up as adolescents (12-23y). Absence of childhood insomnia symptoms was ascertained by parent-reports (n=312), while presence of AIS in this subgroup was ascertained by self-reports (n=97). Presence of MHD was ascertained based on the clinical history and physical exam at baseline (n=52). The Pediatric Behavior Scale (PBS) assessed multiple parent-reported behavioral domains.

Results

Children with MHD at baseline had greater levels of difficulty across a variety of internalizing (e.g., anxiety, depression) and externalizing (e.g., impulsivity, hyperactivity) behavioral domains than those without MHD, regardless of whether they developed AIS. However, children with MHD who went on to develop AIS had significantly greater levels of aggressive (p&lt;0.001) and oppositional (p=0.006) behaviors relative to children with MHD who did not develop AIS. In fact, these latter children did not differ from peers without any history of MHD or AIS on levels of aggressive (p=0.820) or oppositional (p=0.436) behaviors.

Conclusion

Children with MHD who present with normative aggressive and oppositional behaviors are less likely to develop AIS. Healthcare providers should consider providing preventative sleep interventions to youth with MHD who are exhibiting comorbid externalizing behaviors.

Support

National Institutes of Health (R01HL136587, R01HL97165, R01HL63772, UL1TR000127)

0319 Sleep Architecture and Neurocognitive and Behavioral Functioning in Youth from the General Population

Introduction

The transition from childhood to adolescence is critical for the onset of psychopathology and reflects significant changes in the sleeping brain. Sleep deprivation studies have shown that rapid eye movement (REM) and non-rapid eye movement (NREM) sleep are differentially involved in specific cognitive functions. The aim of this study was to examine the association of sleep architecture with neurobehavioral outcomes in a population-based sample.

Methods

We studied 700 children (5-12y, 47.1% female, 23.7% minority) and 421 adolescents (12-23y, 46.1% female, 21.8% minority) from the Penn State Child Cohort. All subjects underwent a 9-hour polysomnography and a 4-hour neurobehavioral evaluation. Neurocognitive outcomes included the Stroop test, digit span backwards (DSB), and coding to measure high- and low-order cognitive functions. Behavioral outcomes included the Child/Adult Behavior Checklist to measure internalizing symptoms and externalizing behaviors. Correlation analysis examined the cross-sectional association between sleep architecture and neurocognitive and behavioral outcomes.

Results

In childhood, %REM sleep was negatively associated with DSB scores (r=-0.088, p=0.027), particularly in males (r=-0.167, p=0.002). Furthermore, %NREM sleep was positively associated with DSB scores in males (r=0.126, p=0.021). In adolescent females, %NREM and %REM sleep were positively (r=0.146, p=0.044) and negatively (r=-0.158, p=0.029) associated with DSB scores, respectively. In adolescence, %NREM sleep was negatively associated with internalizing symptoms (r=-0.109, p=0.026).

Conclusion

Male children and female adolescents who spent a higher proportion of the night in NREM sleep had better working memory performance. Adolescent females who spent a lower proportion of the night in NREM sleep had greater internalizing symptoms. This study suggests a role for sleep architecture in neurobehavioral deficits in youth. Future studies are necessary to determine the contributions of low- and high-frequency sleep EEG dynamics to these clinical outcomes.

Support

National Institutes of Health (R01MH118308, R01HL97165, R01HL63772, UL1TR000127)

0457 Insomnia and Cause-Specific Mortality in Men and Women

Introduction

The association of insomnia with an increased risk of mortality has remained inconsistent across studies, which contrasts with accumulating evidence linking this prevalent and chronic sleep disorder with cardiovascular, cerebrovascular, oncologic, and psychiatric morbidity. The higher prevalence of insomnia in women compared to men may be an important contributor to the different survival rates reported in large, population-based studies.

Methods

The Penn State Adult Cohort is a random, general population sample of 1,741 adults (48.8±13.6y, 52.2% women) who were studied in the sleep laboratory and followed-up for their cause of death up to December 31, 2018. Insomnia was defined as a chronic complaint lasting at least 1 year (n=199). We assessed the risk of all-cause mortality (n=664) and the two most common causes of death: cardiovascular/cerebrovascular (n=275) and cancer (n=161). Cox proportional hazard models adjusted for age, race, sex, education, smoking, alcohol, BMI, AHI, cognitive impairment, mental health problems and physical health problems, including hypertension, diabetes, heart disease, stroke and cancer at baseline.

Results

The risk of all-cause mortality associated with insomnia was significantly increased in men (HR=1.84, 95%CI=1.18-2.87) but not in women (HR=0.80, 95%CI=0.57-1.13; p for sex-interaction&lt;0.01). Insomnia was significantly associated with an increased risk of cardiovascular/cerebrovascular mortality in men (HR=2.11, 95%CI=1.14-3.99), but not in women (HR=0.98, 95%CI=0.59-1.63; p for sex-interaction=0.06). Insomnia was not significantly associated with an increased risk of cancer mortality either in men (HR=1.41, 95% CI=0.56-3.56) or in women (HR=0.90, 95% CI=0.45-1.80), after adjusting for hypertension, diabetes, heart disease, stroke and cancer at baseline.

Conclusion

Men with chronic insomnia are at an increased risk of mortality, particularly that of cardiovascular/cerebrovascular origin. There is a need for translational studies focused on sex-differences that can disentangle the biological and behavioral mechanisms underlying women’s resilience.

Support

American Heart Association (14SDG19830018), National Institutes of Health (R01HL51931, R01HL40916)

0878 Association of Obstructive Sleep Apnea with Internalizing Symptoms vs. Externalizing Behaviors in Adolescents with Attention Deficit Hyperactivity Disorder

Introduction

Attention deficit hyperactivity disorder (ADHD) in children has been associated with insomnia, obstructive sleep apnea (OSA), and abnormal periodic limb movements (PLMS). However, there is lack of data examining the contribution of OSA to ADHD-related internalizing symptoms and externalizing behaviors in adolescents.

Methods

We studied the Penn State Child Cohort, a random general population sample of 700 children (8.7±1.7y), of whom 421 were followed-up 8.3 years later during adolescence (17.0±2.3y, 53.9% male). All adolescents underwent a 9-hour PSG, clinical history and physical examination. ADHD was ascertained by a parent- or self-report of having been diagnosed with ADHD. OSA was defined as an apnea hypopnea index (AHI) of ≥2 events per hour of sleep, while a periodic limb movement index (PLMI) ≥5 events per hour of sleep was indicative of PLMS. Controls, OSA-alone, ADHD-alone and ADHD+OSA were identified. The Child or Adult Behavior Checklist were used to ascertain internalizing and externalizing behaviors. Multivariable-adjusted models controlled for sex, race, age, and body mass index (BMI) percentile.

Results

As compared to controls, adolescents with ADHD-alone or ADHD+OSA had significantly greater externalizing behaviors (p&lt;0.001), inattention (p&lt;0.001) and thought problems (p&lt;0.001). While adolescents with ADHD-alone had higher internalizing symptoms (p=0.021), specifically withdrawn-depression (p&lt;0.01), adolescents with ADHD+OSA had more somatic problems than controls (p=0.048). There were no statistically significant differences in behavioral outcomes between controls and adolescents with OSA-alone or between adolescents with ADHD-alone and ADHD+OSA.

Conclusion

Adolescents with comorbid ADHD and OSA do not present with worse behavioral outcomes than those with ADHD alone. Future studies should examine whether the progression of these adolescents into young adulthood differs in terms of their behavioral outcomes and development of mental health disorders.

Support

National Institutes of Health (R01HL136587, R01HL97165, R01HL63772, UL1TR000127)

0890 Sleep Disordered Breathing is Associated With Endothelial Dysfunction and Atherosclerosis in Young Adults: Preliminary Longitudinal Findings in the Penn State Child Cohort

Introduction

Sleep disordered breathing (SDB) in middle-age is an established risk factor for cardiovascular disease. However, population-based studies supporting its cardiovascular contribution at earlier stages of development are lacking, particularly with long-term follow-ups.

Methods

The Penn State Child Cohort is a population-based longitudinal sample of 700 children (8.7±1.7y), of whom 421 were followed-up 8.3 years later during adolescence (17.0±2.3y) with in-lab polysomnography (PSG). To date, 425 have been followed-up another 7.4 years later during young adulthood (24.4±2.6y) via a standardized survey and 136 of them (55.1% female, 21.3% racial/ethnic minority) have undergone a repeat of their PSG to ascertain apnea/hypopnea index. Subjects (n=121) also underwent Doppler ultrasounds to assess flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT). Linear regression models stratified by body mass index in young adulthood.

Results

SDB was cross-sectionally associated with lower FMD (β=-0.239, p=0.008) and greater CIMT (β=0.330, p&lt;0.001) in young adulthood. Longitudinally, childhood (n=121) and adolescence (n=90) SDB were significantly associated with CIMT (β=0.327, p&lt;0.001 and β=0.286, p=0.006, respectively), but not with FMD (β=-0.158, p=0.08 and β=-0.101, p=0.35, respectively). These associations, particularly longitudinal ones between childhood and adolescence SDB with CIMT in young adulthood, were stronger in overweight than normal weight subjects (e.g., β=0.310, p=0.030 and β =0.089, p=0.582, respectively).

Conclusion

SDB and obesity appear to be synergistically associated with endothelial dysfunction and atherosclerosis in young adults from the general population. These data suggest that a childhood exposure to chronic SDB is associated with long-term atherosclerosis, while endothelial dysfunction may be a short-term outcome. This ongoing 16-year longitudinal study will test whether the natural history of SDB from childhood through adolescence into young adulthood shows differential trajectories for cardiovascular morbidity.

Support

National Institutes of Health (R01HL136587, R01HL97165, R01HL63772, UL1TR000127)

Shock-Induced Damage and Dynamic Fracture in Cylindrical Bodies Submerged in Liquid

Understanding the response of solid materials to shock loading is important for mitigating shock-induced damages and failures, as well as advancing the beneficial use of shock waves for material modifications. In this paper, we consider a representative brittle material, BegoStone, in the form of cylindrical bodies and submerged in water. We present a computational study on the causal relationship between the prescribed shock load and the resulting elastic waves and damage in the solid material. A recently developed three-dimensional computational framework, FIVER, is employed, which couples a finite volume compressible fluid solver with a finite element structural dynamics solver through the construction and solution of local, one-dimensional fluid-solid Riemann problems. The material damage and fracture are modeled and simulated using a continuum damage mechanics model and an element erosion method. The computational model is validated in the context of shock wave lithotripsy and the results are compared with experimental data. We first show that after calibrating the growth rate of microscopic damage and the threshold for macroscopic fracture, the computational framework is capable of capturing the location and shape of the shock-induced fracture observed in a laboratory experiment. Next, we introduce a new phenomenological model of shock waveform, and present a numerical parametric study on the effects of a single shock load, in which the shock waveform, magnitude, and the size of the target material are varied. In particular, we vary the waveform gradually from one that features non-monotonic decay with a tensile phase to one that exhibits monotonic decay without a tensile phase. The result suggests that when the length of the shock pulse is comparable to that of the target material, the former waveform may induce much more significant damage than the latter one, even if the two share the same magnitude, duration, and acoustic energy.

The biomechanical properties of the urethra in boys with hypospadias: a preliminary study

PURPOSE

The ventral aspect of the penis in boys with hypospadias is composed of dysplastic tissue of the skin and the urethra. The aim of this study was to assess the pre-operative size and biomechanical properties of urethrae in boys with and without hypospadias using a more objective catheter-based system.

MATERIALS & METHODS

In this non-blinded clinical observation study, the study population consisted of 19 boys with hypospadias-the case group (median age 13.9 months [range: 12.2-21.3])-and seven boys without hypospadias-the control group (median age 8.5 months [range: 3.8-18.1]). Modified measurements of impedance were used to assess the size, compliance and viscoelasticity of the urethrae under stepwise increased pressures (between 0, 40 and 60 cmH₂O) using a customised Endolumenal Functional Lumen Imaging probe (EndoFLIP®).

RESULTS

The sizes of the urethrae in boys with hypospadias are variable but tend towards being narrower and less compliant than those of the control subjects i.e. median diameter for meatus urethra was 3.2 mm (range: 2.98-3.92) in the hypospadias group compared with 3.64 (range: 3.22-4.44) in the control group at 40 cmH₂O, and the median change in diameter at meatus urethra was 0.08 mm (range: -0.02 to 0.52) in the hypospadias group compared with 0.23 mm (range: -0.02 to 0.34) when the pressure was increased from 40 to 60 cmH₂O. This biomechanical analysis found that there was no significant viscoelasticity of the urethral meatus in both the groups, whereas the remainder of the urethral structure generally had viscoelastic properties in the control group, seen as a creep on the time/diameter curves (Figure). In the group of boys with hypospadias, evaluations of the urethrae revealed varying viscoelastic abilities, ranging from abilities that were comparable with those of the control subjects to no sign of viscoelasticity at all.

CONCLUSIONS

This study is the first to measure the biomechanical properties of the urethra in children, which might help to provide an understanding as to the structural and functional changes associated with hypospadias. The urethrae in the subjects with hypospadias were variable in diameter but tended to be narrower overall, especially in the distal portion of the urethra. Furthermore, the urethrae in boys with hypospadias were frequently less viscoelastic than those of controls.

CLINICAL RELEVANCE

The EndoFLIP® system may be a future way of objectively estimating the severity of a urethral obstruction and could potentially be included in the postoperative assessment of patients with signs of hampered voiding.

Predictors of Early and Late Mortality in Older Kidney Transplant Recipients

BACKGROUND

Older kidney patients with chronic kidney disease benefit significantly from kidney transplantation. However, these older transplant recipients have greater mortality after transplantation than younger transplant recipients. Understanding the impact of comorbidities on post-transplant mortality can improve risk stratification and patient selection.

METHODS

A single-center analysis of 3105 kidney transplant recipients was performed over a 12-year period. Comorbidities associated with death were evaluated in older and younger transplant recipients.

RESULTS

The 2 most important factors associated with increased mortality in the first 100 days after transplant were recipient age ≥60 and receipt of deceased donor organs (adjusted odds ratios, 3.29 and 5.80, respectively), with no statistically significant impact of recipient comorbidities. In the later post-transplant period (after the first 100 days), recipient age ≥60 and receipt of deceased donor organs (adjusted hazard ratios [HR] of 2.14 and 2.29, respectively) remained predictors of mortality. We also found that donor age ≥60 and the recipient having cardiovascular disease and diabetes were independent predictors of increased mortality. There was a statistically significant interaction between diabetes and heart disease and recipient age ≥60, with a lesser impact on late mortality in older patients compared to younger patients.

CONCLUSIONS

This analysis suggests that comorbidities have a larger impact later after transplantation, with less effect on older recipients. These observations suggest that certain comorbid conditions should be evaluated differently in older patients compared to younger ones.

Childhood obesity, weight loss and developmental trajectories predict the persistence and remission of childhood sleep-disordered breathing

BACKGROUND

Obesity has been recognized as a risk factor for childhood sleep-disordered breathing (SDB), yet it remains unclear how obesity and weight change predict the course of childhood SDB.

OBJECTIVE

The objective of the study is to investigate the role of body weight, upper airway abnormalities and developmental trajectories on the persistence and remission of childhood SDB in the transition to adolescence.

METHODS

The Penn State Child Cohort is a representative population sample of 700 children (5-12 years), of whom 421 were followed up as adolescents (12-23 years). Participants underwent a clinical history, physical examination and polysomnography at both time points.

RESULTS

Obesity and enlarged tonsils were cross-sectionally associated with childhood SDB. Longitudinally, baseline obesity predicted the persistence of childhood SDB (OR = 3.75, 95% CI = 2.00-7.05), while weight loss predicted its remission (OR = 1.67, 95% CI = 1.11-2.50). Children with enlarged tonsils who remitted from SDB had not experienced significant weight loss and only 4.4% had undergone adeno/tonsillectomy. Body fat distribution/composition at follow-up was similar in those who had remitted from childhood SDB as compared with those who had never experienced SDB, while those who persisted with childhood SDB showed significant android distribution and visceral adiposity at follow-up.

CONCLUSIONS

Our data support a causal role for obesity and weight loss in the chronicity and remission, respectively, of childhood SDB in the transition to adolescence and suggest that remission of SDB is related to developmental trajectories of the upper airway in a significant proportion of children. Thus, targeting childhood obesity and weight gain should be a priority in the prevention and treatment of SDB during this critical developmental period.

Association of PON1 gene polymorphisms with polycystic ovarian syndrome risk: a meta-analysis of case-control studies

PURPOSE

Evidences showed that paraoxonase 1 (PON1) gene polymorphism has an impact on women's susceptibility to polycystic ovarian syndrome (PCOS) by influencing the expression and activity of PON1. However, the effects of three PON1 polymorphisms (- 108 C>T, L55M and Q192R) on the incidence of PCOS have generated inconsistent results. Here, we conducted a meta-analysis to investigate the association between PON1 polymorphisms and PCOS risk.

METHODS

All eligible trials were identified via systematic searches of multiple literature databases. Outcome data were synthesized by using crude odds ratio with 95% confidence interval. Heterogeneity was assessed with the I² test. Publication bias and subgroup analyses were also performed.

RESULTS

A total of 2449 cases and 1977 controls from nine studies were selected for analysis. The pooled results showed a significant association between PCOS risk and PON1 - 108 C/T polymorphism in the following genetic models [allelic, 0.72 (0.56-0.92); homozygote, 0.51 (0.32-0.82); heterozygote, 0.44 (0.25-0.78); and dominant 0.47 (0.29-0.77)]. For the PON1 192 Q/R polymorphism, a significant relationship was found in the allelic model [0.62 (0.41-0.93)] and recessive model [0.61 (0.37-0.98)]. PCOS risk was also linked to PON1 L55M polymorphism in the heterozygote model [0.62 (0.39-0.98)] and dominant model [0.63 (0.41-0.96)].

CONCLUSIONS

Our study has shown that PON1 - 108 C/T polymorphism might be associated with increased risk of PCOS under the allelic, homozygote, heterozygote, and dominant models. Additionally, PON1 192 Q/R and L55M polymorphisms were significantly related only in the allelic and recessive model, and in the heterozygote and dominant model, respectively.

Sevoflurane activates hippocampal CA3 kainate receptors (Gluk2) to induce hyperactivity during induction and recovery in a mouse model

BACKGROUND

In addition to general anaesthetic effects, sevoflurane can also induce hyperactive behaviours during induction and recovery, which may contribute to neurotoxicity; however, the mechanism of such effects is unclear. Volatile anaesthetics including isoflurane have been found to activate the kainate (GluK2) receptor. We developed a novel mouse model and further explored the involvement of kainate (GluK2) receptors in sevoflurane-induced hyperactivity.

METHODS

Maximal speed, mean speed, total movement distance and resting percentage of C57BL/6 mice were quantitatively measured using behavioural tracking software before and after sevoflurane anaesthesia. Age dependence of this model was also analysed and sevoflurane-induced hyperactivity was evaluated after intracerebral injection of the GluK2 receptor blocker NS-102. Neurones from the hippocampal CA3 region were used to undertake in vitro electrophysiological measurement of kainate currents and miniature excitatory postsynaptic potential (mEPSP).

RESULTS

Sevoflurane induced significant hyperactivities in mice under sevoflurane 1% anaesthesia and during the recovery period, characterized as increased movement speed and total distance. The hyperactivity was significantly increased in young mice compared with adults (P<0.01) and pre-injection of NS-102 significantly prevented this sevoflurane-induced hyperactivity. In electrophysiological experiments, sevoflurane significantly increased the frequency of mEPSP at low concentrations and evoked kainate currents at high concentrations.

CONCLUSIONS

We developed a behavioural model in mice that enabled characterization of sevoflurane-induced hyperactivity. The kainate (GluK2) receptor antagonist attenuated these sevoflurane-induced hyperactivities in vivo, suggesting that kainate receptors might be the underlying therapeutic targets for sevoflurane-induced hyperactivities in general anaesthesia.

Esophagogastric junction in systemic sclerosis: A study with the functional lumen imaging probe

BACKGROUND

Fibrosis and atrophy of esophageal smooth muscle cells cause gastro-esophageal reflux and dysphagia in most patients with systemic sclerosis (SSc). Recent studies indicate that distensibility of the esophagogastric junction (EGJ), assessed with the Functional Lumen Imaging Probe (FLIP) may be a more sensitive and accurate measure of sphincter function than manometry. We aim to describe and compare distension parameters of the EGJ in a well-characterized group of patients with SSc.

METHOD

Twelve patients with SSc reporting reflux or dysphagia (11 women, median age 53 [range 35-72], duration of disease: 1-20 years) were investigated using distensibility testing of the EGJ. Patients were compared with 11 healthy volunteers (HV) (10 women, median age 53 [range 40-68]). The pressure and minimum diameter along the EGJ during ramp distension were used for distensibility analysis.

KEY RESULTS

Patients with SSc had significantly lower EGJ yield pressure (median: 4.0 mm Hg [Inter Quartile Range (IQR): 2.8-7.7]) than HV (median: 6.2 mm Hg [IQR: 9.4-26]) (P=.007). Likewise, the pressure-strain elastic modulus was lower in SSc patients (median 1.73 kPa [IQR: 1.16-2.15]) than in HV (median 2.41 kPa [IQR: 1.85-2.67]) (P=.03), indicating the reduced resistance to distension in SSc patient.

CONCLUSION & INFERENCES

Patients with SSc and symptoms of reflux and dysphagia have significantly reduced resistance to distension of the EGJ.

Low-residue diet fed to rabbits induces histomorphological and biomechanical remodeling of small intestine

BACKGROUND

The composition of ingested food is important for the gut microbiome and intestinal homeostasis. We have previously demonstrated that the structure and mechanical properties in the small intestine remodel significantly during fasting. However, it is not clear to what extent the intestinal mechanical properties changes when the composition of food is changed. This study aimed to investigate the passive biomechanical properties and intestinal tissue remodeling in rabbits fed a low-residue diet.

METHODS

New Zealand rabbits (control group n=6, intervention group n=7) were studied. Segments from duodenum, jejunum and ileum were excised. The intestinal diameter and length were obtained from digitized images of the segments at preselected luminal pressure levels and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data referenced to the zero-stress state geometry. Histomorphometric data were also obtained.

KEY RESULTS

The wet weight-per-unit length, wall thickness and wall area decreased in the intervention group (P<.05, P<.01). Histological measurement confirmed that the wall thickness decreased in all three segments, which was primarily due to mucosal thinning (P<.05). The opening angle tended to increase in all segments in the intervention group. Significant difference between the two groups was found for the jejunum (P<.05). Feeding the low-residue diet shifted the circumferential stress-strain curves in the intervention group to the right, indicating intestinal wall softening.

CONCLUSIONS & INFERENCES

Low-residue diet in rabbits for 1 month induces location-dependent histomorphometric and biomechanical remodeling of the intestine.

Increased yield pressure in the anal canal during sacral nerve stimulation: a pilot study with the functional lumen imaging probe

BACKGROUND

Sacral nerve stimulation (SNS) is a well-established treatment for fecal incontinence but its mode of action remains obscure. Anal sphincter function is usually evaluated with manometry but resistance to distension may be a more appropriate parameter than luminal pressure. The functional lumen imaging probe allows detailed description of distension properties of the anal canal. Our objective in this study was to characterize the impact of SNS on distension properties of the anal canal in patients with idiopathic fecal incontinence.

METHODS

We studied 10 women (median age 64 [44-79] years) with idiopathic fecal incontinence at baseline and during SNS. The luminal geometry of the anal canal was examined with the FLIP at rest and during squeeze and the distensibility of the anal canal was investigated during filling of the bag.

KEY RESULTS

All patients were successfully treated with SNS and the mean Wexner Incontinence Score was reduced from 14.9 ± 4 to 7.1 ± 4.8 (P<.001). The pressure required to open the narrowest point of the anal canal during distension (yield pressure) increased from 14.5 ± 12.2 mmHg at baseline to 20.5 ± 13.3 mmHg during SNS (P<.01). The pressure-strain elastic modulus increased non-significantly from 2.2 ± 0.5 to 2.9 ± 1.6 kPa, indicating increased stiffness of the anal canal.

CONCLUSION AND INFERENCES

The yield pressure and the resistance to distension increased in response to SNS for idiopathic fecal incontinence. This will inevitably increase the resistance to flow through the anal canal, which may contribute to the benefits of sacral nerve stimulation.

The relative association of obstructive sleep apnea, obesity and excessive daytime sleepiness with incident depression: a longitudinal, population-based study

Background

It is postulated that obstructive sleep apnea (OSA) is a risk factor for the development of depression. However, obesity and excessive daytime sleepiness (EDS) are associated with both OSA and depression. The goal of this study was to examine the relative contribution of OSA, obesity, and EDS to incident depression.

Methods

A representative random sample of 1,137 adults without depression from the Penn State Adult Cohort was followed-up after 7.5 years. All subjects underwent a full medical examination and polysomnography (PSG) at baseline. OSA was defined as an apnea/hypopnea index (AHI) ≥ 5, overweight as a body mass index (BMI) of 25-29.9 kg/m², obesity as a BMI ≥ 30 kg/m², and EDS as moderate-to-severe drowsiness/sleepiness and/or irresistible sleep attacks.

Results

Overweight, obesity, and EDS were associated with incident depression, whereas OSA alone was not. Overweight was associated with incident depression in women, while obesity and EDS were associated with incident depression in both genders. The association of overweight and obesity with incident depression was independent of premorbid emotional distress, while that of EDS was not. The association between BMI and EDS with incident depression was stronger in women 20-40 years old. The severity of EDS predicted incident depression in those with OSA, while AHI or oxygen desaturation did not.

Conclusions

Overweight, obesity and EDS are the main predictors of incident depression. Obesity may be linked to depression through psychobiological mechanisms, while EDS may be an early sign of depression. Obesity should be a target of our preventative strategies for depression.

Renoprotective effect of atorvastatin on STZ-diabetic rats through inhibiting inflammatory factors expression in diabetic rat

OBJECTIVE

Though increasing evidences showed that statins had potential benefits to diabetic kidney disease (DKD), its mechanism has not been completely elucidated yet. The aim of this study was to investigate the renoprotective effects of atorvastatin on DKD.

MATERIALS AND METHODS

Kidney injury was induced by streptozotocin (STZ) in rats. STZ-diabetic rats were treated with atorvastatin (10 mg/kg/d) for consecutive 8 weeks. Renal functional and morphological changes were evaluated by clinical biochemistry and histological examination. The expression of inflammatory factors in kidney was measured by real-time (RT)-PCR and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared with DKD rat, atorvastatin effectively reduced the levels of low-density lipoprotein cholesterol (LDL-C), creatinine (CREA), ratio of urine albumin to creatinine (UACR) (p <0.05). The expression of inflammatory factors TNF-α, MCP-1 and IL-6 in kidney tissue were significantly down-regulated, as well (p <0.05). Atorvastatin improved kidney injury with the reduced morphologic lesions and renal fibrosis and the increasing transforming growth factor-β (TGF-β) and collagen I staining.

CONCLUSIONS

Our results suggested that atorvastatin could ameliorate DKD through inhibiting pro-inflammatory pathways. Atorvastatin may possess a potential antidiabetic effect and serve as the therapeutic drug for DKD management.

Acetylation of HDAC1 and degradation of SIRT1 form a positive feedback loop to regulate p53 acetylation during heat-shock stress

The tumor suppressor p53 is an essential transcription factor that sensitively regulates cellular responses to various stresses. Acetylation, a critically important posttranslational modification of p53, is induced in response to cellular stresses. P53 acetylation level strongly correlates with protein stability and activity. The steady-state level of p53 acetylation is balanced by dynamic acetylation and deacetylation. Despite the function of p53 acetylation being well studied, how the steady state of p53 acetylation level is regulated in response to cellular stresses remains unclear. In particular, the dynamic regulation of the deacetylase activities responsible for p53 deacetylation during cellular stress is unknown. In the current study, we investigated the dynamic regulation of HDAC1 (histone deacetylase 1) and SIRT1 (sirtuin 1), two major enzymes for p53 deacetylation, during cell stress. We found that various cell stress events induce HDAC1 acetylation. The increased level of HDAC1 acetylation correlates with the level of p53 acetylation. Acetylated HDAC1 loses the ability to deacetylate p53. Cellular stresses also promote the decline of the SIRT1 protein in a proteasome-dependent pathway, which also results in the increase of p53 acetylation. Importantly, the decreased level of SIRT1 also contributes to the accumulation of HDAC1 acetylation as SIRT1 deacetylates HDAC1. Therefore, the increase of HDAC1 acetylation and reduced level of SIRT1 protein during cellular stress directly link to the induction of p53 acetylation. These results unveil the mechanism underlying the dynamic regulation of p53 acetylation during cell stress.

Upregulation of microRNA-200a associates with tumor proliferation, CSCs phenotype and chemosensitivity in ovarian cancer

Ovarian cancer is a lethal gynecologic malignancy and always has a poor prognosis. Despite new treatments modalities, the long term outcomes had not been significantly improved in the past 30 years. Although microRNA-200a (miR-200a) has been reported to be a prognostic marker in ovarian cancer, it's exact role in ovarian cancer remain unclear. In this study, we inserted the response element of miR-200a in ovarian cancer cell line via lentivirus-mediated transgene in vitro, and qRT-PCR (real time quantitative reverse transcription PCR) assay confirmed that miR-200a was up regulated compared with control. Then colony-formation assay, cell cycle analysis, CCK8 assays in vitro and xenograft experiments in vivo were performed and verified that miR-200a promoted proliferation, while blocked the formation of tumor spheroids and reduced the ratio of SP (side population) cells in ovarian cancer. Finally, we invalidated that miR-200a significantly enhanced the chemosensitivity of paclitaxel but not cisplatin in both adherent culture and sphere culture. Taken together, we demonstrated that upregulation miR-200a promoted proliferation and inhibited CSCs phenotype in OVCAR-3 ovarian cancer cell line, combined with cell cycle-targeting drug paclitaxel could effectively eliminate the "side effects" of proliferation, and showed evidences that this strategy may be promising for ovarian cancer treatment.

Associations between physical activity-related miRNAs and metabolic syndrome

The aim of the study was to investigate the associations between physical activity (PA)-related miRNAs and metabolic syndrome (MetS). A case-control study was conducted in 209 subjects with MetS and 234 controls. The MetS was defined by the International Diabetes Foundation (IDF) criteria of 2005. Serum PA-related miRNAs were detected by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays. Association analysis was performed by logistic regression models. The expression levels of miR-126 and miR-130a were lower in the highest metabolic equivalent hours per week (MET-h/week) quartile than in the lowest quartile [miR-126: Q5 vs. Q1, median (5-95%), 1.67 (0.54, 2.45) vs. 1.35 (0.45, 2.45), p=0.012; miR-130a: Q5 vs. Q1, median (5-95%), 0.90 (0.44, 1.35) vs. 0.53 (0.26, 1.01), p<0.001]. However, miR-197 exhibited a trend with increased MET-h/week [Q5 vs. Q1, median (5-95%), 1.35 (0.45, 2.63) vs. 2.18 (0.87, 4.77), p=0.009]. MiR-126 increased MetS risk significantly while the effect of miR-197 was opposite (miR-126: OR=1.37, 95% CI 1.07-1.75; p=0.012; miR-197: OR=0.68, 95% CI 0.51-0.92; p=0.010). Individuals in the highest MET-h/week quartile had lower prevalence and odds rate of MetS compared with those in the lowest quartile (Q4 vs. Q1: OR=0.58, 95% CI 0.33-1.05; p for trend=0.026). However, further adjustment of both PA associated miRNAs abolished that association. All these results suggested that the association between PA and MetS risk might partly depend on miR-126 and miR-197.

Distensibility of the anal canal in patients with idiopathic fecal incontinence: a study with the Functional Lumen Imaging Probe

BACKGROUND

Anatomical structures and their distensibility vary along the length of the anal canal. The anal sphincter muscles have dynamic properties that are not well-reflected by standard manometry. Abnormal distensibility of the anal canal may be of importance in idiopathic fecal incontinence (IFI). The functional lumen imaging probe (FLIP) allows detailed studies of the distensibility and axial variation of sphincters. We aimed at comparing segmental distensibility of the anal canal in patients with IFI and healthy subjects.

METHODS

The FLIP was used for distension of the anal canal in 22 patients with IFI (17 female, age 27-82 years) and 21 healthy volunteers (18 female, age 32-73 years). The distensibility was determined from changes in luminal diameter. Closure of the anal canal during voluntary squeeze was computed as the combined length of closed anal canal and time. Pressure-strain elastic modulus was computed at rest.

KEY RESULTS

In all subjects, the proximal anal canal was the most distensible segment. During distension at rest and during squeeze the middle and distal anal canal became significantly larger in IFI than in healthy (F < 22.4, p < 0.05). The closure of the anal canal during voluntary squeeze did not differ between healthy (75.9 ± 92.9 mm s) and IFI patients (90.4 ± 105 mm s; p = 0.6). Compared with healthy, IFI patients had lower pressure-strain elastic modulus of the middle and distal (q > 4.5, p < 0.05) but not the proximal anal canal (q < 0.7, p > 0.05).

CONCLUSIONS & INFERENCES

Patients with IFI have increased distensibility of the middle and distal parts of the anal canal.

Distension-evoked motility analysis in human esophagus

BACKGROUND

The major function of the esophagus is to transport food from the mouth to the stomach by peristaltic muscle action. However, only few techniques exist for detailed evaluation of motor activity of the esophagus in vivo. The aim of this study is to use distension combined with manometry and impedance planimetry [pressure-cross-sectional area (P-CSA) recordings] to assess esophageal peristaltic motor function in terms of the mechanical energy output, and to examine the change in the motor activity of the esophagus in response to butylscopolamine, an anticholinergic drug known to impair the smooth muscle contraction in the gastrointestinal tract.

METHODS

The probe with CSA measurements was positioned 7 cm above the lower esophageal sphincter in 16 healthy volunteers before and during butylscopolamine administration. Distension-evoked esophageal peristalsis was analyzed using P-CSA data during distension up to pressures of 5 kPa. The P-CSA, work output (area of the tension-CSA curves), and propulsive tension were analyzed.

KEY RESULTS

The wave-like peristalsis resulted in P-CSA loops consisting of relaxation and contraction phases. The work increased with the distension pressure (from 1311 ± 198 to 16 330 ± 1845 μJ before butylscopolamine vs from 2615 ± 756 to 11 404 ± 1335 μJ during butylscopolamine administration), and propulsive tension increased from 18.7 ± 1.9 to 88.5 ± 5.5 N m(-1) before the drug and from 23.1 ± 3.9 to 79.5 ± 3.3 N m(-1) during butylscopolamine administration). Significantly, lower values were found during butylscopolamine administration compared with the distension before using the drug (P < 0.01).

CONCLUSIONS & INFERENCES

Esophageal muscle properties during peristalsis can be assessed in vivo in terms of mechanical energy output parameters. Butylscopolamine impaired muscle contraction which could be detected as altered contraction parameters. The analysis can be further used as an adjunct tool of the combined manometry and impedance planimetry recordings to derive advanced esophageal motor function parameters for studying the physiological and pathophysiological mechanical consequences of esophageal contractions.

Downregulation of transcription factor SOX2 in cancer stem cells suppresses growth and metastasis of lung cancer

Background:

The cancer stem cell hypothesis suggests that neoplastic clones are maintained exclusively by a small subpopulation of cells, which have indefinite proliferation and differentiation potentials and give rise to phenotypically diverse cancer cells. Cancer stem cells have been isolated by their ability to efflux Hoechst 33342 dye and are referred to as the ‘side population’ (SP).

Methods and results:

The Hoechst efflux assay was used to isolate and characterize the SP from murine D121 lung carcinoma cells. Here, we demonstrated that D121-SP cells contain cancer stem cell characteristics, that is, upregulation of the transcription factors SOX2 and Oct 4 in D121-SP cells. In addition, the migration of D121-SP was decreased, and apoptosis of D121-SP was upregulated following knocking down of SOX2 in D121 cells. Importantly, downregulation of SOX2 in D121 cells markedly suppressed their metastatic potential in syngeneic mice.

Conclusions:

These results suggest that the SP is an enriched source of lung tumour cells with stem cell properties and that SOX2 has an important role in maintaining stem cell properties and functions that may be a potential target for effective lung cancer therapy.

Part 5. Public health and air pollution in Asia (PAPA): a combined analysis of four studies of air pollution and mortality

BACKGROUND

In recent years, Asia has experienced rapid economic growth and a deteriorating environment caused by the increasing use of fossil fuels. Although the deleterious effects of air pollution from fossil-fuel combustion have been demonstrated in many Western nations, few comparable studies have been conducted in Asia. Time-series studies of daily mortality in Asian cities can contribute important new information to the existing body of knowledge about air pollution and health. Not only can these studies verify important health effects of air pollution in local regions in Asia, they can also help determine the relevance of existing air pollution studies to mortality and morbidity for policymaking and environmental controls. In addition, the studies can help identify factors that might modify associations between air pollution and health effects in various populations and environmental conditions. Collaborative multicity studies in Asia-especially when designed, conducted, and analyzed using a common protocol-will provide more robust air pollution effect estimates for the region as well as relevant, supportable estimates of local adverse health effects needed by environmental and public-health policymakers.

SPECIFIC OBJECTIVES

The Public Health and Air Pollution in Asia (PAPA*) project, sponsored by the Health Effects Institute, consisted of four studies designed to assess the effects of air pollution on mortality in four large Asian cities, namely Bangkok, in Thailand, and Hong Kong, Shanghai, and Wuhan, in China. In the PAPA project, a Common Protocol was developed based on methods developed and tested in NMMAPS, APHEA, and time-series studies in the literature to help ensure that the four studies could be compared with each other and with previous studies by following an established protocol. The Common Protocol (found at the end of this volume) is a set of prescriptive instructions developed for the studies and used by the investigators in each city. It is flexible enough to allow for adjustments in methods to optimize the fit of health-effects models to each city's data set. It provides the basis for generating reproducible results in each city and for meta-estimates from combined data. By establishing a common methodology, factors that might influence the differences in results from previous studies can more easily be explored. Administrative support was provided to ensure that the highest quality data were used in the analysis. It is anticipated that the PAPA results will contribute to the international scientific discussion of how to conduct and interpret time-series studies of air pollution and will stimulate the development of high-quality routine systems for recording daily deaths and hospital admissions for time-series analysis.

METHODS

Mortality data were retrieved from routine databases with underlying causes of death coded using the World Health Organization (WHO) International Classification of Diseases, 9th revision or 10th revision (ICD-9, ICD-10). Air quality measurements included nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with aerodynamic diameter < or = 10 microm (PM10), and ozone (O3) and were obtained from several fixed-site air monitoring stations that were located throughout the metropolitan areas of the four cities and that met the standards of procedures for quality assurance and quality control carried out by local government units in each city. Using the Common Protocol, an optimized core model was established for each city to assess the effects of each of the four air pollutants on daily mortality using generalized linear modeling with adjustments for time trend, seasonality, and other time-varying covariates by means of a natural-spline smoothing function. The models were adjusted to suit local situations by correcting for influenza activity, autocorrelation, and special weather conditions. Researchers in Hong Kong, for example, used influenza activity based on frequency of respiratory mortality; researchers in Hong Kong and Shanghai used autoregressive terms for daily outcomes at lag days; and researchers in Wuhan used additional smoothing for periods with extreme weather conditions.

RESULTS AND DISCUSSION

For mortality due to all natural (nonaccidental) causes at all ages, the effects of air pollutants per 10-microg/m3 increase in concentration was found to be higher in Bangkok than in the three Chinese cities, with the exception of the effect of NO2 in Wuhan. The magnitude of the effects for cardiovascular and respiratory mortality were generally higher than for all natural mortality at all ages. In addition, the effects associated with PM10 and O3 in all natural, cardiovascular; and respiratory mortality were found to be higher in Bangkok than in the three Chinese cities. The explanation for these three findings might be related to consistently higher daily mean temperatures in Bangkok, variations in average time spent outdoors by the susceptible populations, and the fact that less air conditioning is available and used in Bangkok than in the other cities. However, when pollutant concentrations were incorporated into the excess risk estimates through the use of interquartile range (IQR), the excess risk was more comparable across the four cities. We found that the increases in effects among older age groups were greater in Bangkok than in the other three cities. After excluding data on extremely high concentrations of PM10 in Bangkok, the effect estimate associated with PM10 concentrations decreased in Bangkok (suggesting a convex relationship between risk and PM10, where risk levels off at high concentrations) instead of increasing, as it did in the other cities. This leveling off of effect estimates at high concentrations might be related to differences in vulnerability and exposure of the population to air pollution as well as to the sources of the air pollutant. IMPLICATIONS OF THE STUDY: The PAPA project is the first coordinated Asian multicity air pollution study ever published; this signifies the beginning of an era of cooperation and collaboration in Asia, with the development of a common protocol for coordination, data management, and analysis. The results of the study demonstrated that air pollution in Asia is a significant public health burden, especially given the high concentrations of pollutants and high-density populations in major cities. When compared with the effect estimates reported in the research literature of North America and Western Europe, the study's effect estimates for PM10 were generally similar and the effect estimates for gaseous pollutants were relatively higher. In Bangkok, however, a tropical city where total exposures to outdoor pollution might be higher than in most other cities, the observed effects were greater than those reported in the previous (i.e., Western) studies. In general, the results suggested that, even though social and environmental conditions across Asia might vary, it is still generally appropriate to apply to Asia the effect estimates for other health outcomes from previous studies in the West. The results also strongly support the adoption of the global air quality guidelines recently announced by WHO.