Influences of approaching tropical cyclones on water vapor and aerosols in the atmospheric boundary layer of Guangdong-Hong Kong-Macau Greater Bay Area of China.

The outer circulation of tropical cyclones (TCs) on the western North Pacific has been reported to substantially influence the atmospheric environment over the Guangdong-Hong Kong-Macau Greater Bay Area (GBA) of China, whereas dynamic evolution and redistribution of water vapor and aerosol in the atmospheric boundary layer (ABL) responding to moving TCs have yet to be understood. This study aims to answer three key research questions related to the influences of the approaching TCs: (1) how do water vapor and aerosol particles over the GBA change during the TC approaching stage? (2) how does the ABL in terms of vertical wind structure respond to the approaching TCs? and (3) how does turbulence influence the vertical profile of aerosol during the approaching stage? Based on an intensive analysis of three-year reanalysis and Doppler LiDAR data, this study identified a dry-polluted time over the GBA when a TC was located at ~1000 km away on South China Sea. Before that, horizontal wind has consistently come from the northeast, creating a favorable condition for weak transboundary air pollution to the GBA. During the dry-polluted time, the highest surface PM2.5 concentration was resulted from the enhanced downdraft and early-stage wind shear, i.e., stronger wind started occurring at upper-level ABL, while the further turbulent mixing induced by wind shear enhancement and updrafts recovery pumped surface pollution upward to the upper level when TCs became closer. Our findings are expected to improve both weather and PM2.5 forecasts under the impacts of approaching TCs.

Assessment of SARS-CoV-2 Immunity in Convalescent Children and Adolescents.

Persistence of protective immunity for SARS-CoV-2 is important against reinfection. Knowledge on SARS-CoV-2 immunity in pediatric patients is currently lacking. We opted to assess the SARS-CoV-2 adaptive immunity in recovered children and adolescents, addressing the pediatrics specific immunity towards COVID-19. Two independent assays were performed to investigate humoral and cellular immunological memory in pediatric convalescent COVID-19 patients. Specifically, RBD IgG, CD4+, and CD8+ T cell responses were identified and quantified in recovered children and adolescents. SARS-CoV-2-specific RBD IgG detected in recovered patients had a half-life of 121.6 days and estimated duration of 7.9 months compared with baseline levels in controls. The specific T cell response was shown to be independent of days after diagnosis. Both CD4+ and CD8+ T cells showed robust responses not only to spike (S) peptides (a main target of vaccine platforms) but were also similarly activated when stimulated by membrane (M) and nuclear (N) peptides. Importantly, we found the differences in the adaptive responses were correlated with the age of the recovered patients. The CD4+ T cell response to SARS-CoV-2 S peptide in children aged <12 years correlated with higher SARS-CoV-2 RBD IgG levels, suggesting the importance of a T cell-dependent humoral response in younger children under 12 years. Both cellular and humoral immunity against SARS-CoV-2 infections can be induced in pediatric patients. Our important findings provide fundamental knowledge on the immune memory responses to SARS-CoV-2 in recovered pediatric patients.

Nuclear accident consequence assessment in Hong Kong using JRODOS.

The JRODOS (Java-based Real-time Online DecisiOn Support) is a decision support system for off-site emergency management for releases of radioactive material into the environment. This paper documents the application of JRODOS by the Hong Kong Observatory in accident consequence assessment and emergency preparedness studies. For operational considerations, the most computational efficient dispersion model in JRODOS, ATSTEP, is adopted. Verification studies for JRODOS's ATSTEP model have been conducted. Comparison with tracer experiment results showed that under neutral atmospheric conditions and distances up to 50 km, the JRODOS simulation outputs were in general of the same order of magnitude with the tracer data. To further evaluate the capability of JRODOS in short-range simulation, a case study on the Fukushima nuclear power plant accident was also carried out. JRODOS was able to produce realistic simulation results which were comparable to the actual airborne monitoring data of the Cs-137 ground deposition from the Fukushima accident. Furthermore, the results of a comprehensive study to assess the potential consequences of accidents at a nearby nuclear power station are presented. Simulation using the French S3 source term for the Guangdong Nuclear Power Station at Daya Bay showed that the projected effective doses within Hong Kong remain far below the IAEA generic criteria of projected dose for urgent protective actions in sheltering/evacuation, while the projected equivalent dose in thyroid may meet the IAEA generic criteria for use of thyroid blocking agent at some areas in the northeastern part of Hong Kong, at distances of up to about 40 km from Daya Bay depending on the prevailing weather conditions in different seasons.

Clinical impact of minimal residual disease in children with different subtypes of acute lymphoblastic leukemia treated with Response-Adapted therapy.

To determine the clinical significance of minimal residual disease (MRD) in patients with prognostically relevant subtypes of childhood acute lymphoblastic leukemia (ALL), we analyzed data from 488 patients treated in St Jude Total Therapy Study XV with treatment intensity based mainly on MRD levels measured during remission induction. MRD levels on day 19 predicted treatment outcome for patients with hyperdiploid >50 ALL, National Cancer Institute (NCI) standard-risk B-ALL or T-cell ALL, while MRD levels on day 46 were prognostic for patients with NCI standard-risk or high-risk B-ALL. Patients with t(12;21)/(ETV6-RUNX1) or hyperdiploidy >50 ALL had the best prognosis; those with a negative MRD on day 19 had a particularly low risk of relapse: 1.9% and 3.8%, respectively. Patients with NCI high-risk B-ALL or T-cell ALL had an inferior outcome; even with undetectable MRD on day 46, cumulative risk of relapse was 12.7% and 15.5%, respectively. Among patients with NCI standard-risk B-ALL, the outcome was intermediate overall but was poor if MRD was ⩾1% on day 19 or MRD was detectable at any level on day 46. Our results indicate that the clinical impact of MRD on treatment outcome in childhood ALL varies considerably according to leukemia subtype and time of measurement.

Treatment of irritable bowel syndrome with a novel colonic irrigation system: a pilot study.

BACKGROUND: Medical treatments for irritable bowel syndrome (IBS) are often disappointing. A colonic irrigation system, the Ashong colonic irrigation apparatus (ACIA), was designed as a patient-administered device for defecation disorders. This pilot study evaluated the efficacy and safety of ACIA for IBS. METHODS: Eighteen patients, 12 with constipation-dominant IBS (IBS-C) and 6 with diarrhea-dominant IBS (IBS-D) group, were studied. Patients were randomized into treatments of 1-4 weeks. Colonic irrigation was performed twice daily for 6 consecutive days per week. To determine the response to treatment, bowel movement frequency, stool consistency, abdominal pain, patient satisfaction with bowel movements, and distress/discomfort due to symptoms were assessed. RESULTS: The scores of abdominal pain (p < 0.001), satisfaction (p < 0.001), and distress/discomfort (p < 0.001) improved significantly. The frequency of bowel movements in the IBS-C group increased from 1.68 to 3.78 times per week (p < 0.001). The occurrence of Bristol Stool Scale type 1 and 2 stool passage decreased from 45 to 13 % (p = 0.009) in the IBS-C group and type 6 and 7 stools decreased from 62 to 28 % (p = 0.005) in the IBS-D group. Only mild adverse events occurred, and all patients completed treatment. CONCLUSIONS: Colonic irrigation with ACIA is safe and can improve abdominal pain, constipation, and diarrhea associated with IBS. Patients were more satisfied with their bowel movements and found their symptoms were less disturbing. Larger studies on long-term efficacy and quality of life and on placebo effects are needed.

A revised definition for cure of childhood acute lymphoblastic leukemia.

With improved contemporary therapy, we reassess long-term outcome in patients completing treatment for childhood acute lymphoblastic leukemia (ALL) to determine when cure can be declared with a high degree of confidence. In six successive clinical trials between 1984 and 2007, 1291 (84.5%) patients completed all therapies in continuous complete remission. The post-therapy cumulative risk of relapse or development of a second neoplasm and the event-free survival rate and overall survival were analyzed according to the presenting features and the three treatment periods defined by relative outcome. Over the three treatment periods, there has been progressive increase in the rate of event-free survival (65.2% vs 74.8% vs 85.1% (P<0.001)) and overall survival (76.5% vs 81.1% vs 91.7% (P<0.001)) at 10 years. The most important predictor of outcome after completion of therapy was the type of treatment. In the most recent treatment period, which omitted the use of prophylactic cranial irradiation, the post-treatment cumulative risk of relapse was 6.4%, death in remission 1.5% and development of a second neoplasm 2.3% at 10 years, with all relapses except one occurring within 4 years of therapy. None of the 106 patients with the t(9;22)/BCR-ABL1, t(1;19)/TCF3-PBX1 or t(4;11)/MLL-AFF1 had relapsed after 2 years from completion of therapy. These findings demonstrate that with contemporary effective therapy that excludes cranial irradiation, approximately 6% of children with ALL may relapse after completion of treatment, and those who remain in remission at 4 years post treatment may be considered cured (that is, less than 1% chance of relapse).

Autonomic dysfunction in different subtypes of post-acute ischemic stroke.

OBJECTIVES: Central autonomic impairment is frequent in ischemic stroke at acute or chronic stages. The mechanism by which these symptoms occur in patients with ischemic stroke has not been elucidated. This study sought to investigate cardiovascular autonomic function in patients with different subtypes of post-acute ischemic stroke. METHODS: 77 ischemic stroke patients [50 patients with large-artery atherosclerosis (LAA) and 27 patients with small-vessel occlusion (SVO), average 6 months after stroke onset] and 37 elderly controls were recruited. All performed Ewing's battery autonomic function tests and power spectral analysis of heart rate variability (HRV). RESULTS: Stroke patients with both LAA and SVO had significantly lower low frequency power spectral density than controls. The prevalence of autonomic dysfunction in both groups (82.0% patients with LAA and 63.0% with SVO) was higher than that in controls (21.6%). Patients with LAA showed impairment of all parasympathetic tests (all P<0.05) and one of the sympathetic tests (mean fall in systolic blood pressure on standing: P = 0.058) and those with SVO only showed impairment in two parasympathetic tests (heart rate response to deep breathing: P = 0.010; heart rate response to standing: P = 0.004) in comparison with controls. Patients with LAA had significantly more impairment than those with SVO in some autonomic parameters (Valsalva ratio: P = 0.039; mean fall in systolic blood pressure on standing: P = 0.015). CONCLUSIONS: Irrespective of the subtype of the ischemia, post-acute stroke patients showed a parasympathetic cardiac deficit. Additionally, parasympathetic and sympathetic cardiovascular modulations were more severely impaired in patients with LAA.

Regularized multiframe phase-shifting algorithm for three-dimensional profilometry.

In many industrial inspection systems, it is required to have a high-precision three-dimensional measurement of an object under test. A popular technique is phase-measuring profilometry. In this paper, we develop some phase-shifting algorithms (PSAs). We propose a novel smoothness constraint in a regularization framework; we call this the R-PSA method and show how to obtain the desired phase measure with an iterative procedure. Both the simulation and experimental results verify the efficacy of our algorithm compared with current multiframe PSAs for interferometric measurements.

Osteonecrosis in children after allogeneic hematopoietic cell transplantation: study of prevalence, risk factors and longitudinal changes using MR imaging.

Osteonecrosis after hematopoietic SCT (HCT) has seldom been addressed in pediatric populations. At our institution, since January 2002, children undergoing allogeneic HCT (alloHCT) receive yearly follow-up magnetic resonance imaging (MR) of hips and knees. To estimate the prevalence, longitudinal changes and associated risk factors for osteonecrosis after alloHCT, we reviewed MRs for children who underwent single alloHCT during the study period. We analyzed 149 of 344 patients who had post-HCT MR imaging performed (84 males; median age 11 years (range, 0.5-21 years)), median follow-up time was 32.6 months (range, 2.8-97.2 months). In all, 44 (29.5%) developed osteonecrosis of hips and/or knees; of those, 20 (45%) had at least 30% epiphyseal involvement. In 23 (52%), osteonecrosis lesions were identified in the first and in 43 (98%) by the third yearly scan. Knees were more frequently involved than hips; severity of osteonecrosis was greater in hips. Those who had pre-alloHCT osteonecrosis, two patients' hips and six patients' knees resolved completely; three patients' osteonecrosis lesions regressed after alloHCT. On risk factor analysis, age at time of alloHCT (P=0.051) and osteonecrosis identified by MRs before alloHCT (P=0.001) were the primary risk factors. This analysis shows that preventive strategies for osteonecrosis in this population should focus on measures to minimize risk factors before alloHCT.

Autonomic dysfunction in ischemic stroke with carotid stenosis.

OBJECTIVES: Impaired autonomic function is common in acute ischemic stroke. Previous limited studies have suggested that atherosclerosis may affect the distensibility of the carotid sinus and then impair the cardiovascular autonomic function. This study sought to investigate cardiovascular autonomic function in patients with ischemic stroke with carotid stenosis. METHODS: Eighty-five patients with ischemic stroke (58 ones without carotid stenosis and 27 ones with carotid stenosis, average 6 months after stroke onset) and 37 elderly controls were recruited. All performed Ewing's battery autonomic function tests. RESULTS: From Ewing's battery of autonomic function tests, atypical, definite, or severe autonomic dysfunction was identified in 69.0% patients without carotid stenosis and 88.9% with carotid stenosis, with significant difference between the two groups, and the prevalence of autonomic dysfunction in both groups was higher than that in controls (21.6%). Patients with carotid stenosis showed impairment of all parasympathetic tests (all P < 0.05) and one of the sympathetic tests [Mean fall in systolic blood pressure (BP) on standing: P = 0.051], and those without carotid stenosis only showed impairment in two parasympathetic tests (Valsalva ratio: P = 0.014; heart rate response to deep breathing: P < 0.001) in comparison with controls. Patients with carotid stenosis had significantly more impairment than those without carotid stenosis in some autonomic parameters (Valsalva ratio: P < 0.05; mean fall in systolic BP on standing: P < 0.05). CONCLUSIONS: Cardiovascular autonomic function is impaired in patients with ischemic stroke, but patients with carotid stenosis show more severely impaired parasympathetic and sympathetic functions.

Cognitive and functional impairments in ischemic stroke patients with concurrent small vessel and large artery disease.

BACKGROUND AND PURPOSE: Concurrent small vessel, intracranial and extracranial large artery disease (SLAD) is common in Asian but its impact on cognitive and functional outcomes is unclear. We aimed to evaluate the clinical, cognitive and functional outcomes in ischemic stroke patients with SLAD. METHODS: Chinese ischemic stroke patients with diffuse white matter lesions (WMLs) were recruited as part of the VITATOPS Trial. They were studied with MRI and MRA of brain. Various neuropsychiatric batteries were used to assess the cognitive functions. RESULTS: Totally 97 patients with acute ischemic stroke and diffuse WMLs were included, of whom 44 (45%) had SLAD. Patients with SLAD had lower Mini Mental State Examination (MMSE) when compared with the patients without SLAD. They had more behavioral symptoms and caused more stress in caregivers as assessed by the Neuropsychiatric Inventory (NPI). Multivariate regression analysis showed SLAD contributed significantly to MMSE, NPI Patient (NPI P) and NPI Care Giver (NPI CG). Among 44 patients with SLAD, 30 (68%) had severe cognitive impairment. They were older and less educated. They had more diabetes and poorer performance in neuropsychiatric tests including Mattis Dementia Rating Scale Initiation/Perseveration subset (MDRS I/P) and Clinical Dementia Rating (CDR). They also had poorer functional outcomes as assessed by Barthel Index (BI) and Instrumental activities of daily living (IADL). CONCLUSIONS: This was the first MRA-based study to take into consideration the clinical, cognitive and functional outcomes in ischemic stroke patients with SLAD. Patients with SLAD had poorer cognitive and functional outcomes when compared to patients without SLAD.

Impaired neurovascular coupling in ischaemic stroke patients with large or small vessel disease.

BACKGROUND AND PURPOSE: There is limited data of neurovascular coupling on stroke patients, especially on comparison of different etiologies. We aim to test the hypothesis that patients with small vessel disease (SVD) are impaired on neurovascular coupling rather than stroke patient with large intracranial artery stenosis (LIAS), because small vessel is more associated with microcirculatory function. To assess microcirculatory integrity of stroke patients, we performed a functional transcranial Doppler test using a standardized visual stimulation test. METHODS: The neurovascular coupling was measured in the asymptomatic occipital cortex in ischaemic stroke patients with LIAS, SVD, and healthy elder controls. Bilateral posterior cerebral arteries were monitored to measure evoked flow velocity during resting and visual stimulation phase. Peak systolic flow velocity responses were recorded, and time course of hemodynamic response was modeled according to a control system analysis with the parameters gain, natural angular frequency, attenuation, and rate time. RESULTS: Reproduced for both sides, the functionally induced flow velocity changes (gain) were significantly lower in LIAS and SVD compared with controls (P < 0.001). Reductions in both stroke groups were in the same order. Neurovascular coupling in LIAS group did not show difference at the side of vessel stenosis compared with non-stenosis side or at different stenotic degrees. CONCLUSIONS: Interestingly, both LIAS and SVD showed an uncoupling of the blood supply of active neurons. This points to an additional small vessel dysfunction in patients with LIAS.

Prevalence of osteonecrosis and associated risk factors in children before allogeneic BMT.

Osteonecrosis (ON) is a debilitating long-term complication of allogeneic BMT (allo-BMT), but may begin before allo-BMT in some children because of their primary disease treatment. Therefore, to estimate the prevalence and associated risk factors for ON before allo-BMT, we conducted a retrospective analysis of magnetic resonance (MR) studies of 118 children who underwent first allo-BMT at our institution between December 2000 and September 2007. Of the 118 consecutive patients, 107 (90.7%) underwent prospective MR studies irrespective of symptoms (69 males; median age at allo-BMT 12.9 years), and 11 underwent MR studies for symptoms. Among the 107 who had prospective imaging, 23 (21.5%) had ON; nearly 50% had at least 30% epiphyseal involvement. Knees were more frequently involved than were hips; severity of ON was greater in hips. ON prevalence before allo-BMT was 23.72% when all 118 patients were included in the denominator. Risk factor analysis, limited to MR studies performed irrespective of symptoms, revealed female gender (P=0.049) and age 10 years at the time of MR study (P=0.03) as significant risk factors, and primary diagnosis of lymphoid malignancies and aplastic anemia trended toward significance. ON before allo-BMT is a common occurrence in children.

Genetic polymorphisms of Chinese patients with ischemic stroke and concurrent stenoses of extracranial and intracranial vessels.

The etiology of concurrent stenoses of extracranial and intracranial vessels in patients with ischemic stroke is poorly understood, but hereditary factors are believed to be important. We aimed to determine whether genetic polymorphisms affecting homocysteine and lipid metabolism are associated with concurrent stenoses. The genotypes of 191 Han Chinese patients with acute ischemic stroke, of whom 47 (25%) had concurrent stenoses, and 167 healthy control patients in Hong Kong were examined for the following polymorphisms: paraoxonase 1 (PON1) Q192R, methylenetetrahydrofolate reductase (MTHFR) A222V, glutamate-cysteine ligase catalytic-subunit (GCLC)-129C>T, and oxidized low-density lipoprotein receptor (OLR) 3' untranslated region C>T (rs1050283). The genotype distributions of PON1 Q192R and MTHFR A222V, which affect lipid and homocysteine metabolism, differed significantly between patients with stroke and healthy controls. The presence of at least one R allele in PON1 Q192R and a TT allele in OLR rs1050283 were associated with concurrent stenoses. We also identified a possible association between the presence of at least one V allele in MTHFR A222V and concurrent stenoses. This study shows that genetic polymorphisms affecting homocysteine and lipid metabolism are possible risk factors for stroke and concurrent stenoses.

The significance of microembolic signals and new cerebral infarcts on the progression of neurological deficit in acute stroke patients with large artery stenosis.

BACKGROUND: Early neurological deterioration is common in the acute phase after stroke. We sought to investigate the correlation between the progression of microembolic signal (MES), ischemic infarcts and the neurological deficits in the acute phase of stroke patients with large artery occlusive disease. METHODS: Transient ischemic attack or stroke patients with relevant significant large artery stenosis (> or =50% diameter reduction) and admitted within 7 days of the symptom onset were recruited in this study. MES, infarcts on diffusion-weighted imaging and National Institutes of Health Stroke Scale (NIHSS) score were assessed on days 1 and 7 of recruitment. RESULTS: Among 67 patients, 50.7% (34 of 67) had MES on day 1. Presence of MES correlated with both a higher number of infarcts (p = 0.006) and the incidence of multiple infarcts (chi(2) test, p = 0.002), but not with the NIHSS score. On day 7, MES was detected in 25.4% of the patients (17 of 67), 11.8% of them (2 of 17) displayed new or extended infarct on DWI (p = 0.14) and 29.4% (5 of 17) showed neurological improvement (p = 0.039). Among the patients with positive MES at baseline, NIHSS reduction was positively correlated with disappearance of MES on day 7 (MES disappearance vs. persistence group, 2.05 vs. 0.73, p = 0.023). CONCLUSIONS: Neither the disappearance of MES nor the changes in NIHSS score correlated with the progression of infarct. Disappearance of MES indicated better neurological improvement in the acute phase.

Long-term outcomes of ischemic stroke patients with concurrent intracranial and extracranial stenoses and ischemic heart disease.

BACKGROUND AND PURPOSE: Coexisting ischemic heart disease (IHD) and concurrent atherosclerosis of intracranial and extracranial vessels is common in Asians. This study aims to investigate the long-term outcomes of ischemic stroke patients with concurrent stenoses and IHD. METHODS: This was a prospective cohort study in Hong Kong. Consecutive Chinese patients with acute ischemic stroke underwent MRI, magnetic resonance angiography and carotid duplex sonography. RESULTS: A total of 428 patients were included. The mean follow-up period was 65 months (up to 87 months). Ninety-three patients (22%) died of any cause and 104 patients (22%) suffered from nonfatal vascular events. Fifty-four patients (13%) had IHD. Among them, 27 patients (50%) had concurrent stenoses. In patients with concurrent stenoses and IHD, only 3 (11%) were free of death and recurrent vascular events. Eight (30%) had recurrent nonfatal stroke, 7 (26%) had nonfatal myocardial infarct (MI) and 11 (41%) died, 6 (22%) of them due to fatal MI. The overall 5-year cumulative rates of mortality, recurrent vascular events and combined poor outcomes were 21, 23 and 43%, respectively. In patients with concurrent stenoses and IHD, these rates were 40, 50 and 83%, respectively. More deaths (log rank: 6.56; p = 0.01), recurrent vascular events (log rank: 25.24; p < 0.001) and poor outcomes (log rank: 27.50; p < 0.001) were found among patients with concurrent stenoses and IHD. CONCLUSIONS: Ischemic stroke patients with concurrent stenoses and IHD had high risks of death and recurrent vascular events. Future studies on aggressive medical therapy and early cardiac interventions in this high-risk group of stroke patients are warranted.

Use of magnetic resonance angiography to predict long-term outcomes of ischemic stroke patients with concurrent stenoses in Hong Kong.

PURPOSE: To determine the long-term outcome of ischemic stroke patients with concurrent intracranial and extracranial atherosclerosis using magnetic resonance angiography. METHODS: A prospective cohort of patients in Hong Kong with acute ischemic stroke was studied with magnetic resonance angiography of the brain and carotid duplex. All patients were followed up regularly for the development of recurrent stroke, cardiac events, or death. RESULTS: Totally 343 patients with acute ischemic stroke were included, of whom 104 (30%) had concurrent intracranial and extracranial lesions. The follow-up period was up to 76 months (mean 44.5 months). Overall, 55 patients (15.5%) died of any cause and 91 patients (26.5%) suffered a further nonfatal vascular event. The overall 5-year cumulative rates of mortality, restroke and poor outcomes (combined death and further vascular events) were 18, 27 and 37%, respectively. In patients with concurrent lesions, these rates were 31, 41 and 51%, respectively. The corresponding rates were 13, 22 and 31% in patients without concurrent lesions. The risks were highest in the first year after stroke. More deaths (log rank, 16.3; p = 0.0001), restrokes (log rank, 9.71; p = 0.002) and poor outcomes (log rank, 13.87; p = 0.0001) were found among patients with concurrent lesions. The presence of concurrent vascular lesions, advanced age, smoking, hyperlipidemia and previous history of stroke were independent predictors of poor outcomes. CONCLUSIONS: The long-term prognosis of ischemic stroke patients with concurrent atherosclerosis of intracranial and extracranial vessels is poor. They are at high risk of further vascular events or death.