A study of hospitalized COVID-19 patients with AKI in a setting of multiracial developing country

BACKGROUND

The commonest indication for hospitalization in COVID-19 patients is hypoxemia or severe respiratory symptoms. However, COVID-19 disease may result in extrapulmonary complications including kidney-related pathology. The reported incidence of renal involvement related to COVID infection varies based on geographical location.

OBJECTIVE

This study aimed to assess the incidence rate of AKI in hospitalized COVID-19 patients and identify risk factors and prognostic predictors.

METHOD

In this retrospective study, we recruited hospitalized COVID-19 patients from January 2021 until June 2021 at the University Malaya Medical Center. The inclusion criteria were hospitalized for ≥ 48 h with confirmed COVID-19 infection and at least 18 years old. Patient demographic and clinical data were collected from electronic medical records. The staging of AKI was based on criteria as per KDIGO guidelines.

RESULTS

One thousand five hundred twenty-nine COVID patients fulfilled the inclusion criteria with a male-to-female ratio of 759 (49.6%) to 770 (50.3%). The median age was 55 (IQR: 36-66). 500 patients (32.7%) had diabetes, 621 (40.6%) had hypertension, and 5.6% (n = 85) had pre-existing chronic kidney disease (CKD). The incidence rate of AKI was 21.1% (n = 323). The percentage of COVID patients in different AKI stages of 1,2 and 3 were 16.3%, 2.1%, and 2.7%, respectively. Fifteen hospitalized patients (0.98%) required renal replacement therapy. 58.8% (n = 190) of AKI group had complete recovery of kidney function. Demographic factors included age (p < 0.001), diabetes (p < 0.001), hypertension (p < 0.012), CKD (p < 0.001), and vaccination status (p = 0.042) were associated with an increased risk of developing AKI. We found that the AKI cohort had statistically significant lower platelet counts and higher ferritin levels than the non-AKI cohort. AKI is a risk predictor of prolonged hospitalization (p < 0.001) and higher mortality rates (P < 0.001).

CONCLUSION

AKI is a common clinical complication among hospitalized COVID-19 patients. The etiology of AKI is multifactorial and may have an adverse impact on patient morbidity and mortality.

A novel cardiac arrest severity score for the early prediction of hypoxic-ischemic brain injury and in-hospital death

Funding Acknowledgements

Type of funding sources: None.

Background

Out-of-hospital cardiac arrest (OHCA) outcomes are unsatisfactory despite postcardiac arrest care. Early prediction of prognoses might help stratify patients and provide tailored therapy.

Purpose

In this study, we derived and validated a novel scoring system to predict hypoxic-ischaemic brain injury (HIBI) and in-hospital death (IHD).

Methods

We retrospectively analysed Korean Hypothermia Network prospective registry data collected from in Korea between 2015 and 2018. Patients without neuroprognostication data were excluded, and the remaining patients were randomly divided into derivation and validation cohorts. HIBI was defined when at least one prognostication predicted a poor outcome. IHD meant all deaths regardless of cause. In the derivation cohort, stepwise multivariate logistic regression was conducted for HIBI and IHD scores, and model performance was assessed. We then classified patients into four categories and analysed associations between the categories and cerebral performance categories (CPCs) at hospital discharge. Finally, we validated our models in the internal validation cohort.

Results

Among 1373 patients, 240 were excluded, and 1133 were randomised into derivation (n=754) and validation cohorts (n=379). In the derivation cohort, 7 and 8 predictors were selected for HIBI (0–8) and IHD scores (0–11), respectively, and the area under the curve (AUC) was 0.85 (95% CI 0.82–0.87) and 0.80 (95% CI 0.77–0.82), respectively. Applying optimum cutoff values of ≥6 points for HIBI and ≥7 points for IHD, patients were classified as follows: HIBI (-)/IHD (-), Category 1 (n=424); HIBI (-)/IHD (+), Category 2 (n=100); HIBI (+)/IHD (-), Category 3 (n=21); and HIBI (+)/IHD (+), Category 4 (n=209). CPCs at discharge were significantly different in each category (p&lt;0.001). In the validation cohort, the model showed moderate discrimination (AUC 0.83, 95% CI 0.79–0.87 for HIBI and AUC 0.77, 95% CI 0.72–0.81 for IHD) with good calibration. Each category of the validation cohort showed a significant difference in discharge outcomes (p&lt;0.001) and a similar trend to the derivation cohort.

Conclusions

We presented a novel approach for assessing illness severity after OHCA. Although external prospective studies are warranted, risk stratification for HIBI and IHD could help provide OHCA patients with appropriate treatment.

1524 Design and Implementation Of ICE-COVID, A Double-Blind Randomised Placebo-Controlled Trial on The Efficacy of Iota-Carrageenan Nasal and Throat Spray for Covid-19 Prophylaxis

Introduction

The severity of Covid-19 infection is associated with viral load. For infection to occur, viruses including SARS-CoV-2 must first penetrate the respiratory mucus to attach to the host cell surface receptors. Iota-carrageenan (I-C), a sulphated polysaccharide extracted from red edible seaweed, has shown efficacy against a range of viruses in clinical trials, through prevention of viral entry into respiratory host cells and in-vitro activity against SARS-CoV-2. Our aim, as an academic surgical department, was to design and implement a clinical trial to investigate whether I-C nasal and throat sprays are effective in reducing the rate and severity of Covid-19 infection.

Method

The study is a single centre, double-blinded randomised controlled trial. Recruitment of 480 participants aged ≥18 years without previous Covid-19 infection and who have not yet been vaccinated, commenced in December 2020. Participants are randomised to either the treatment (0.12% I-C in 0.5% saline spray) or placebo (0.5% saline spray) arm and will prophylactically apply the spray to their nose and throat while completing a daily symptom tracker for a total of 10 weeks. The primary outcome is the acquisition of Covid-19 infection. Secondary outcomes include symptom type, severity and duration, subsequent familial/household Covid-19 infection and infection with non-Covid-19 upper respiratory tract infections.

Discussion

Our hypothesis is that I-C sprays will reduce SARS-CoV-2 attachment to the naso- and oropharyngeal mucosal epithelial cells thus reducing the effective viral infective dose. If proven effective, the self-administered prophylactic spray would have wider utility for key workers and the general population.

Trial registration number

NCT04590365

A longitudinal histologic evaluation of vitamin D receptor expression in the skeletal muscles of patients with a distal radius fracture

We investigated the effect of vitamin D supplementation on the expression of muscle vitamin D receptor (VDR) and cross-sectional area (CSA) in patients with a distal radius fracture (DRF). Significant increases in VDR expression and CSA were observed, especially in vitamin D-deficient patients.

PURPOSE

Vitamin D supplementation is known to enhance muscle mass and function, but whether the VDR is essential in this process remains unknown. We evaluated the change in VDR expression and CSA in the forearm muscles following vitamin D supplementation in patients with a DRF.

METHODS

We prospectively recruited 18 women with a median age of 63.5 years who have a DRF. We obtained two biopsies of the forearm muscle, first at the time of fracture repair and then during hardware removal. We supplemented 1000 IU of vitamin D per day during a median interval of 8 months. We examined the changes in VDR expression and CSA by immunohistochemistry.

RESULTS

The median serum 25-hydroxyvitamin D [25(OH)D] increased from 14.3 to 32.1 ng/mL (P = 0.001). The median VDR expression increased from 0.72 to 0.78 (P = 0.002), and the median CSA increased from 1290.0 to 1685.8 μm² (P = 0.022). Significant increases in VDR expression and CSA were observed in vitamin D-deficient patients [25(OH)D] < 20 ng/mL, but not in vitamin D-non-deficient patients. The changes in VDR expression and CSA were in the same direction in 13 patients, but in the opposite direction in 5 patients.

CONCLUSION

Vitamin D supplementation may increase muscle VDR expression and CSA in patients with a DRF, especially in vitamin D-deficient patients. The increase in CSA without an increase in VDR expression in some patients indicates that the effect of vitamin D supplementation on muscle mass could be mediated by indirect effect of serum vitamin D restoration and by VDR.

Retroductal Delivery of Epidermal Growth Factor Protects Salivary Progenitors after Irradiation

Salivary gland hypofunction after irradiation is associated with a deficit of epithelial stem/progenitors in salivary glands. Although epidermal growth factor (EGF) is known to stimulate the proliferation of epithelial cells, the therapeutic effect of EGF on salivary epithelial stem/progenitors remains undetermined. In this study, we administered EGF to submandibular glands (SMGs) via a retrograde route through the SMG excretory duct before fractionated irradiation and examined whether EGF could protect salivary epithelial progenitor cells from radiation and alleviate radiation-induced salivary hypofunction. EGF-treated mice exhibited greater body and gland weights at 12 wk after irradiation than untreated mice. The retroductal delivery of EGF improved salivary secretory function and increased salivary amylase activity in a dose-dependent manner. Histological examinations highlighted the amelioration of the loss of keratine-14⁺ (KRT14⁺) basal ductal and/or MIST1⁺ acinar cells, as well as induction of fibrosis, following irradiation in EGF-treated mice. An additional in vitro experiment using a salivary gland organoid irradiation model indicated that the radioprotective effects of EGF promoted the growth and inhibited the apoptotic cell death of salivary epithelial cells. Our results suggest that retroductal delivery of EGF may be a promising therapeutic option for preventing radiation-induced salivary gland hypofunction.

Slow Gait, Subjective Cognitive Decline and Motoric Cognitive RISK Syndrome: Prevalence and Associated Factors in Community Dwelling Older Adults

BACKGROUND

Motoric Cognitive Risk Syndrome (MCR), slow gait speed (SG) and subjective cognitive decline (SCD) are known to be harbingers of dementia. MCR is known to be associated with a 3-fold increased risk of future dementia, while SG can precede cognitive impairment.

OBJECTIVE

We aim to determine the prevalence and demographics of MCR, slow gait alone (SG-A) and subjective cognitive decline alone (SCD-A) in community-dwelling older adults and association with physical, functional, cognition and psychosocial factors.

METHODS

A total of 509 participants were classified into four groups according to presence of SG and/or SCD. Multinomial logistic regression was used to identify the factors associated with SG-A, SCD-A and MCR.

RESULTS

The prevalence of MCR was 13.6%, SG-A 13.0% and SCD-A 35.0%. Prevalence of MCR doubled every decade in females with 27.7% of female ≥ 80 years old had MCR. Almost 4 in 10 had no SG or SCD (SG+SCD negative). MCR and SG-A groups were significantly older, had higher body mass index (BMI), lower education, lower global cognition scores especially in non-memory domains, higher prevalence of low grip strength and lower short physical performance battery scores than those with SCD-A and SG+SCD negative. In addition, the SG-A group had significantly higher prevalence of multi-morbidity and diabetes. The prevalence of pain, depression, frailty, social isolation and activity of daily living impairment were significantly higher in MCR. The global cognitive and functional scores for those with SCD-A were comparable to the SG+SCD negative group. The Malay ethnic group had the lowest prevalence of SCD but highest prevalence of SG. After adjusting for confounding factors, age, BMI, frailty status, instrumental activity of daily living, depression and pain remained significantly associated with MCR. For SG-A, age, BMI, education and number of chronic diseases remained significant.

CONCLUSION

Both MCR and SG-A are associated with global cognitive decline especially in the non-memory domains and lower functional scores. Gait speed is a good predictor of negative outcomes and should be considered as the 'sixth' vital sign. Long term prospective studies are needed to evaluate: i) the conversion to dementia in different ethnic groups and ii) effect of targeted physical and / or dual task exercise on delaying the conversion to dementia and / or improvement in physical measures and reduction of disability.

Frailty and Quality of Life in Older Adults with Metabolic Syndrome - Findings from the Healthy Older People Everyday (HOPE) Study

OBJECTIVES

Metabolic syndrome (MetS) and frailty are both associated with increased morbidity and mortality. Frailty is associated with reduced quality of life (QoL) but association of QoL with MetS have produced mixed results suggesting that other factors such as disease burden, obesity and depression may have a more significant influence. We aim to investigate the demographics of frail participants with MetS, and relationship between frailty and QoL in MetS.

METHODS

Cross-sectional population study involving 292 older adults ≥ 65 years with MetS. MetS was defined using the Modified ATP III for Asians which requires the presence of 3 or more of the following 5 components 1) waist circumference ≥ 90cm for males or ≥ 80cm for females, 2) TG ≥ 150mg/dL, 3) HDLc < 40mg/dL in males or < 50mg/dL in females, 4) blood pressure ≥ 130/85mmHg or use of anti-hypertensive medication, and 5) fasting plasma glucose ≥ 100mg/dL or use of pharmacological treatment for diabetes mellitus. Data were collected on demographics, frailty (FRAIL), QoL (Euroqol-5D), perceived health, functional status, cognition, Timed-Up-and-Go (TUG), and hand-grip strength (HGS).

RESULTS

40.4% of the participants were pre-frail (MetSprefrail) and 7.2% were frail (MetSfrail). MetSfrail were significantly older, had lower education level, higher polypharmacy burden and higher prevalence of diabetes. The prevalence of at least 1 activity of daily living impairment was 4 times higher, and depression 9 times higher than their robust counterparts. MetSfrail also had longer TUG, higher prevalence of poor grip strength and poor perceived health. After adjusting for age, gender and education, MetSfrail was significantly associated with much higher odds of EQ-5D moderate to extreme problems with mobility (Odds Ratio (OR) =10.99, CI 2.62-46.14), usual activities (OR=37.82, CI 3.77-379.04) and pain (OR=10.79, CI 3.18-36.62). EQ-5D Index Value and Perceived Health improved by 0.1 (Mean Difference (MD) =0.07, CI 0.04-0.10) and 6.0 (MD=6.01, CI 3.29-8.73) respectively as frailty status improved.

CONCLUSION

Frailty in MetS is associated with depression, polypharmacy, greater functional impairment, poorer QoL and perceived health. Frailty screening and personalized management is crucial in MetS as frailty may be a mediator for negative outcomes in MetS, and frailty may be reversible.

Association of Pain and Impact of Dual-Task Exercise on Function, Cognition and Quality of Life

PURPOSE

This study aimed to assess the factors associated with pain and evaluate the impact of dual-task exercise on pain improvement, quality of life (QOL), cognition and function in older adults.

PATIENTS AND METHODS

This study is a secondary data analysis of the HAPPY (Healthy Ageing Promotion Program for You) study. At risk older adults ≥ 60 years old were enrolled in a community dual-task exercise program. Assessments for frailty, sarcopenia, falls, quality of life (QOL) and perceived health, depression, cognition and physical function were performed at baseline and 3 months. Pain intensity was derived from EQ-5D and stratified into no pain, slight pain and moderate to extreme pain.

RESULTS

Out of 296 participants, 37.2% had slight pain and 11.1% had moderate to severe pain. Both slight and moderate to extreme pain compared with no pain group were significantly associated with lower perceived health (68.2,63.6 vs 76.0) and QOL index (0.70,0.59 vs 0.93); moderate to extreme pain was also significantly associated with depression, low mental vitality, frailty, sarcopenia and poorer physical performance. After 3 months of dual-task exercise, pain improved in 70.8% of the moderate to extreme pain group and 50.8% of slight pain group. Significant improvement in perceived health, QOL, physical function and cognition were also observed.

CONCLUSION

Proactive efforts are required to screen for pain and manage frailty, sarcopenia and depression. Dual-task exercise proved safe and possibly effective in reducing pain and improving QOL, physical and cognitive function in older adults. Prospective randomized studies are needed to validate the effectiveness of dual-task vs single-task exercise, including impact of reversal of frailty and sarcopenia in pain management.

Using lactic acid bacteria and packaging with grapefruit seed extract for controlling Listeria monocytogenes growth in fresh soft cheese

Various cheese products are involved in outbreaks of listeriosis worldwide due to high consumption and prolonged refrigerated storage. The objective of this study was to determine the efficacy of using lactic acid bacteria and packaging with grapefruit seed extract (GSE) for controlling Listeria monocytogenes growth in soft cheese. Leuconostoc mesenteroides and Lactobacillus curvatus isolated from kimchi were used as a starter culture to make a soft cheese, which was inoculated with a cocktail strain of L. monocytogenes. The soft cheese was packed with low-density polyethylene, biodegradable polybutylene adipate-co-terephthalate (PBAT), low-density polyethylene with GSE, or PBAT with GSE and stored at 10°C and 15°C. Leuconostoc mesenteroides (LcM) better inhibited the growth of L. monocytogenes than Lb. curvatus. The PBAT with GSE film showed the best control for the growth of L. monocytogenes. When both LcM and PBAT with GSE were applied to the soft cheese, the growth of L. monocytogenes was inhibited significantly more than the use of LcM or PBAT with GSE alone. In all test groups, water activity, pH, and moisture on a fat-free basis decreased, and titratable acidity increased compared with the control group. These results suggest that LcM isolated from kimchi and PBAT with GSE packaging film can be used as a hurdle technology to lower the risk of L. monocytogenes in soft cheese at the retail market.

Intrinsically p-type cuprous iodide semiconductor for hybrid light-emitting diodes

Cuprous halides, characterized by a direct wide band-gap and a good lattice matching with Si, is an intrinsic p-type I-VII compound semiconductor. It shows remarkable optoelectronic properties, including a large exciton binding energy at room temperature and a very small piezoelectric coefficient. The major obstacle to its application is the difficulty in growing a single-crystal epitaxial film of cuprous halides. We first demonstrate the single crystal epitaxy of high quality cuprous iodide (CuI) film grown on Si and sapphire substrates by molecular beam epitaxy. Enhanced photoluminescence on the order of magnitude larger than that of GaN and continuous-wave optically pumped lasing were found in MBE grown CuI film. The intrinsic p-type characteristics of CuI were confirmed using an n-AlGaN/p-CuI junction that emits blue light. The discovery will provide an alternative way towards highly efficient optoelectronic devices compatible with both Si and III-nitride technologies.

Abstract P6-18-26: Ado-trastuzumab for the treatment of metastatic HER2-amplified breast cancer patients previously treated with pertuzumab

BACKGROUND: Ado-trastuzumab (T-DM1) is an antibody-drug conjugate of trastuzumab and a cytotoxic microtubule-inhibitory agent, emtansine. T-DM1 is approved for the treatment of advanced HER2-amplified breast cancer that progressed following trastuzumab-based therapies based on improvement in progression-free survival (PFS) and overall survival (OS) compared to the therapy of physician choice. However, T-DM1 trials were conducted prior to the widespread adoption of docetaxel, trastuzumab, and pertuzumab as standard frontline therapy for advanced HER2-amplified breast cancer. As such, none of the patients enrolled on T-DM1 studies had been exposed to pertuzumab, and the clinical benefit of T-DM1 in patients previously treated with pertuzumab therapy is unknown.

METHODS: We completed a retrospective review of patients at our institution over the age of 18 with metastatic HER2-amplified breast cancer treated with pertuzumab prior to T-DM1 between February 2013 and May 2018. Data was collected on patient and tumor characteristics, number and duration of therapies in the metastatic setting, and clinical outcomes. The primary endpoint of this study was PFS in patients given T-DM1 after earlier exposure to pertuzumab. Secondary endpoints included overall response rate (ORR), prolonged duration of T-DM1 therapy (&gt; 6 months), and OS. Adverse events following T-DM1 were collected using CTCAE 4.03, with a focus on cardiac dysfunction and peripheral neuropathy. Patient features and outcomes were summarized with descriptive statistics and time-to-event measures were analyzed using the Kaplan-Meier method and log-rank test.

RESULTS: Twenty patients met the inclusion criteria and are included in this study. The patient population consisted of 18 non-Hispanic white and 2 black women, with a median age of 58.5 (range 34-68) years. The number of prior systemic therapies (excluding pertuzumab) ranged from 0-8 with a median of 1 therapy. The duration of T-DM1 therapy (started, on average, 24 months after metastatic diagnosis) ranged from &lt; 1 month to 3.5 years with a median of 6 months. T-DM1 therapy was overall very well tolerated, with all adverse events being grade ≤2. Of note, 2 patients had grade 2 neuropathy, and one patient had grade 1 cardiotoxicity, without any change in left ventricular ejection.

Among 18 patients evaluable for response, ORR was 16.7% (95% CI: 3.6% to 41.4%), with 3 patients achieving a partial response. No complete responses were noted. 10/18 (55.6%) patients had prolonged duration of therapy with T-DM1. Median follow-up time after initiation of T-DM1 was 15 months and 6/20 (30%) patients died while under observation. At the time of data cut-off, 10/20 patients had disease progression on T-DM1. Median PFS was 16 months, with a 1-year PFS rate of 54.5% (95% CI: 36.4% to 81.7%). The 1-year OS rate was 75.0% (95% CI: 58.2% to 96.6%). Patients with liver metastases (n=8) had a significantly worse PFS (p=0.003).

CONCLUSION: T-DM1 following pertuzumab is well tolerated and shows excellent efficacy in the treatment of HER2-positive metastatic breast cancer. Comparing T-DM1 following pertuzumab to T-DM1 in pertuzumab-naïve patients should be explored in this patient population.

Citation Format: Al Rabadi LS, Kaempf A, Lim JY, Saraceni MM, Savin MA, Mitri ZI. Ado-trastuzumab for the treatment of metastatic HER2-amplified breast cancer patients previously treated with pertuzumab [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-26.

Depth extraction with offset pixels

Numerous depth extraction techniques have been proposed in the past. However, the utility of these techniques is limited as they typically require multiple imaging units, bulky platforms for computation, cannot achieve high speed and are computationally expensive. To counter the above challenges, a sensor with Offset Pixel Apertures (OPA) has been recently proposed. However, a working system for depth extraction with the OPA sensor has not been discussed. In this paper, we propose the first such system for depth extraction using the OPA sensor. We also propose a dedicated hardware implementation for the proposed system, named as the Depth Map Processor (DMP). The DMP can provide depth at 30 frames per second at 1920 × 1080 resolution with 31 disparity levels. Furthermore, the proposed DMP has low power consumption as for the aforementioned speed and resolution it only requires 290.76 mW. The proposed system makes it an ideal choice for depth extraction systems in constrained environments.

Organotypic Spheroid Culture to Mimic Radiation-Induced Salivary Hypofunction

Radiation treatment often leads to irreversible damage to normal salivary glands (SGs) because of their proximity to head and neck cancers. Optimization of the in vitro model of irradiation (IR)-induced SG damage is warranted to investigate pathophysiology and monitor treatment outcome. Here, we present an organotypic spheroid culture model to investigate the impact of IR on SGs and the mechanisms underlying IR-induced structural and functional changes. Human parotid epithelial cells were obtained from human parotid glands and plated on either plastic plates or Matrigel. A number of 3-dimensional (3D) spheroids were assembled on Matrigel. After IR at 10 and 20 Gy, morphologic changes in cells in 2D monolayers and 3D spheroids were observed. As the structural integrity of the 3D spheroids was destroyed by IR, the expression levels of salivary epithelial and structural proteins and genes decreased proportionally with radiation dosage. Furthermore, the spheroid culture allowed better measurement of functional alterations following IR relative to the monolayer culture, in which IR-inflicted spheroids exhibited a loss of acinar-specific cellular functions that enable Ca²⁺ influx or secretion of α-amylase in response to cholinergic or β-adrenergic agonists. p53-mediated apoptotic cell death was observed under both culture conditions, and its downstream signals increased, such as p53 upregulated modulator of apoptosis (PUMA), Bax, cytochrome c, caspase 9, and caspase 3. These results suggest that the organotypic spheroid culture could provide a useful alternative model for exploration of radiobiology and mode of action of new therapies for prevention of radiation-induced salivary hypofunction.

Cation exchange synthesis of uniform PbSe/PbS core/shell tetra-pods and their use as near-infrared photodetectors

In this work we explore the preparation of complex-shaped semiconductor nanostructures composed of different materials via a cationic exchange process in which the cations of the original semiconductor nanostructure are replaced by cations of different metals with preservation of the shape and the anionic framework of the nanocrystals. Utilizing this cation exchange method, we synthesized two new tetrapods for the first time: Cu2-xSe/Cu2-xS and PbSe/PbS, both prepared from CdSe/CdS tetrapods as 'templates'. We also fabricated near-infrared (NIR) photodetectors with a very simple architecture comprising a PbSe/PbS tetrapod layer between two Au electrodes on a glass substrate. When illuminated by a NIR laser, these devices are capable of achieving a responsivity of 11.9 A W(-1) without the use of ligand-exchange processes, thermal annealing or hybrid device architecture. Transient absorption spectroscopy was carried out on these PbSe/PbS tetrapods, the results of which suggest that the branched morphology contributes in part to device performance. Investigation of the charge dynamics of the PbSe/PbS tetrapods revealed an extremely long-lived exciton recombination lifetime of ∼17 ms, which can result in enhanced photoconductive gain. Overall, these heterostructured tetrapods showcase simultaneously the importance of nanoparticle shape, band structure, and surface chemistry in the attainment of NIR photodetection.

Screening Nuclear Field Fluctuations in Quantum Dots for Indistinguishable Photon Generation

A semiconductor quantum dot can generate highly coherent and indistinguishable single photons. However, intrinsic semiconductor dephasing mechanisms can reduce the visibility of two-photon interference. For an electron in a quantum dot, a fundamental dephasing process is the hyperfine interaction with the nuclear spin bath. Here, we directly probe the consequence of the fluctuating nuclear spins on the elastic and inelastic scattered photon spectra from a resident electron in a single dot. We find the in-plane component of the nuclear Overhauser field leads to detuned Raman scattered photons, broadened over experimental time scales by field fluctuations, which are distinguishable from both the elastic and incoherent components of the resonance fluorescence. This significantly reduces two-photon interference visibility. However, we demonstrate successful screening of the nuclear spin noise, which enables the generation of coherent single photons that exhibit high visibility two-photon interference.

Stability analysis of the Korean prototype Generation-IV sodium-cooled fast reactor using linear frequency domain approach

The Korea Atomic Energy Research Institute (KAERI) has been developing the 150 MWe Prototype Generation-IV Sodium-cooled Fast Reactor (PGSFR). The design concept is highly based on passive safety mechanisms, minimizing the need for engineered safety systems. Presently, it is of primary importance to assure the reactor dynamics and stability against small reactivity disturbances under power operating conditions. KAERI has therefore developed the NuSTAB code for stability analysis of the PGSFR. In NuSTAB, the neutron-kinetic and thermal-hydraulic coupling equations are linearized to form the characteristic equation, which is solved as a generalized eigenvalue problem for determining the decay ratio, an indicator of the system stability. In this paper, the stability of the PGSFR was analyzed by applying the point kinetic and spatial kinetic options in the NuSTAB code. System responses to temperature feedbacks including the Doppler effect, thermal expansion, coolant density change, and overall feedback were studied. The results indicate that the initial U and final TRU cores of the PGSFR are both inherently stable thanks to the temperature feedbacks.

Adverse effects of young maternal age on neonatal outcomes

INTRODUCTION

Teenage pregnancy is associated with poor neonatal outcomes, which may burden the young mothers and their families. The aim of this study was to determine the effect young maternal age and single motherhood has on neonatal outcomes.

METHODS

We conducted a retrospective cohort study of 267 infants born to mothers aged ≤ 21 years in National University Hospital, Singapore, from January 2011 to December 2012. We compared the maternal demographics and neonatal outcomes of single mothers with those of married mothers. The neonatal outcomes of our study cohort were also compared to the hospital's birth cohort during the same period.

RESULTS

Unsatisfactory antenatal care was more prevalent among the young single mothers than among the young married mothers (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.71-4.92, p < 0.01). The infants of the young single mothers had a lower mean birth weight (p = 0.01), with a significant proportion weighing < 2.5 kg (OR 2.91, 95% CI 1.35-6.37, p < 0.01). Young maternal age was linked to a higher incidence of prematurity (OR 1.70, 95% CI 1.18-2.43, p < 0.01), major congenital defects (OR 4.68, 95% CI 2.10-10.13, p < 0.01), and a perinatal mortality of 18.7 per 1,000 births (OR 3.76, 95% CI 1.26-10.32, p = 0.02).

CONCLUSION

Young single mothers were more likely to have unsatisfactory antenatal care and lighter infants. Young maternal age was associated with a higher risk of prematurity, major congenital malformations and perinatal mortality. More studies are needed to ascertain the cause of these adverse outcomes.

Kinetic studies of CO2 methanation over a Ni/γ-Al2O3 catalyst

The production of methane by reacting CO₂ with H₂ (CO₂ methanation) has the potential for producing synthetic natural gas, which could be exported using the existing infrastructure for the distribution of natural gas. The methanation of CO₂ was investigated over a wide range of partial pressures of products and reactants using (i) a gradientless, spinning-basket reactor operated in batch mode and (ii) a laboratory-scale packed bed reactor operated continuously. The rate and selectivity of CO₂ methanation, using a 12 wt% Ni/γ-Al₂O₃ catalyst, were explored at temperatures 445–497 K and pressures up to 20 bar. Research with the batch reactor showed that the rate increased with increasing partial pressures of H₂ and CO₂ when the partial pressures of these reactants were low; however, the rate of reaction was found to be insensitive to changes in the partial pressures of H₂ and CO₂ when their partial pressures were high. A convenient method of determining the effect of H₂O on the rate of reaction was also developed using the batch reactor and the inhibitory effect of H₂O on CO₂ methanation was quantified. The kinetic measurements were compared with a mathematical model of the reactor, in which different kinetic expressions were explored. The kinetics of the reaction were found to be consistent with a mechanism in which adsorbed CO₂ dissociated to adsorbed CO and O on the surface of the catalyst with the rate-limiting step being the subsequent dissociation of adsorbed CO. The ability of the kinetic expressions to predict the results from the continuous, packed-bed reactor was explored, with some discrepancies discussed.

The prognostic significance of pretreatment [18F]FDG-PET/CT imaging in patients with uterine cervical cancer: preliminary results

PURPOSE OF INVESTIGATION

To evaluate the prognostic significance of positron emission tomography/computed tomography (PET/CT) in patients diagnosed with cervical cancer.

MATERIALS AND METHODS

Patients with cervical cancer in FIGO Stages IB1 to IVB were imaged with PET/CT prior to treatment during one of the staging work-ups. The patients were observed for a median of 31.4 months (range, six to 89 months) after the initial treatment. The standardized uptake value (SUV) max of the primary cervical tumor mass was compared with the prognostic factors. RESULTs: A total of 81 patients who were primarily treated with radical hysterectomy (RH, n = 45) or concurrent chemoradiation (CCRT, n = 36) were analyzed. Multivariate analysis indicated that larger tumor size (> 4 cm, OR 8.694, 95% CI, 1.638-46.146), deep stromal invasion (≥ 1 cm, OR 7.249, 95% CI, 1.141-46.039) by the primary tumor, and pathologically confirmed pelvic lymph node involvement (positive, OR 14.586, 95% CI, 2.072-102.674) were significantly associated with recurrence after treatment. However, pretreatment SUVmax was not a significant independent predictor of disease recurrence (OR 1.058, 95% CI, 0.255-4.398).

CONCLUSION

[18F]Fluorodeoxyglucose (FDG) uptake by the primary tumor showed a significant association with several risk factors that have been identified as treatment predictors. However, a high pretreatment SUVmax was not predictive of recurrence in uter- ine cervical cancer patients.

Fabrication of GaAs/Al0.3Ga0.7As multiple quantum well nanostructures on (100) si substrate using a 1-nm InAs relief layer

Nanometer scale thin InAs layer has been incorporated between Si (100) substrate and GaAs/Al0.3Ga0.7As multiple quantum well (MQW) nanostructure in order to reduce the defects generation during the growth of GaAs buffer layer on Si substrate. Observations based on atomic force microscopy (AFM) and transmission electron microscopy (TEM) suggest that initiation and propagation of defect at the Si/GaAs interface could be suppressed by incorporating thin (1 nm in thickness) InAs layer. Consequently, the microstructure and resulting optical properties improved as compared to the MQW structure formed directly on Si substrate without the InAs layer. It was also observed that there exists some limit to the desirable thickness of the InAs layer since the MQW structure having thicker InAs layer (4 nm-thick) showed deteriorated properties.

Multifocal microinvasive squamous cell carcinoma with extensive spread of squamous cell carcinoma in situ (CIS) into the uterine corpus, vagina, and left salpinx diagnosed five years after conization of cervical CIS

BACKGROUND

Multifocal microinvasive squamous cell carcinoma (SCC) with extensive spread of squamous cell carcinoma in situ (CIS) into the uterine corpus, salpinx, and vagina is extremely unusual.

CASE

The authors present a case of 69-year-old woman with hydrometra who was found to have multifocal microinvasive SCC in the endometrium. The CIS had spread superficially throughout the entire endometrium up to the fundus, completely replacing the epithelium. The uterine cervix, vaginal surface and left salpingeal mucosa were involved. She had previously undergone conization due to cervical CIS five years prior. The pathologic reports showed clear resection margins at that time.

CONCLUSION

The present case suggests that CIS in the endometrium spread back to the cervix and vagina, although the definite origin of the first CIS was not determined.

Thoracic vessel injury

Thoracic trauma occurs in an estimated 25% of all trauma victims, with approximately 50% of trauma mortalities attributable to these injuries. Only 4% of thoracic traumas involve injuries to thoracic vessels, including the aorta, innominate veins and artery, left carotid artery, internal mammaries, and pulmonary hilar vessels. These vascular injuries can range from minor to major with advances in prehospital management increasing the number of patients surviving in the field and presenting to the hospital with life-threatening vascular injuries. Rapid assessment during the initial survey and interventions to maintain airway, breathing, and circulation of the patient can be life-saving. The patient's hemodynamic status will often dictate the extent of the initial workup or whether the patient requires emergent operation. Stable patients can undergo further assessment and detailed imaging, such as computed tomography and/or angiography. Treatment of thoracic vessel injuries may include advanced endovascular techniques, traditional open surgery, or non-operative management with observation. The following review systematically details the initial workup, evaluation and management techniques of thoracic vessel injuries.

Elastic properties of polycaprolactone at small strains are significantly affected by strain rate and temperature

Tensile tests were conducted on polycaprolactone at various strain rates and temperatures. Focusing on the mechanical properties within only the small-strain elastic region, i.e. up to the inflection point in the stress–strain diagram, it was found that strain rate and temperature had significant effects on the polymer. This finding implies that the effects of strain rate and temperature on the elastic properties of polycaprolactone should be considered in the design and manufacture of rigidity-sensitive, load-bearing applications, including use as biomaterial for scaffolds in tissue engineering applications.

Delayed ascending aortic pseudoaneurysm in an adult onset Still's disease patient with previous mitral valve and aortic root replacement

A 59-year-old female patient with adult onset Still's disease (AOSD) presented with hemoptysis and pseudoaneurysm from an aortic root vent cannulation site that was created 4 years earlier for combined mitral and aortic valve surgery. The pseudoaneurysm was successfully repaired and the patient remained well during a follow-up period of 20 months.

Assessment of post-stroke extrapersonal neglect using a three-dimensional immersive virtual street crossing program

OBJECTIVE

To investigate the potential of our newly developed three-dimensional immersive virtual reality (VR) program modeled on a real street crossing as an assessment tool for extrapersonal neglect in stroke patients.

METHODS

Thirty-two patients with right-hemispheric stroke (neglect group, 16; non-neglect group, 16) were enrolled. The deviation angle, reaction time, left-to-right reaction time ratio, visual and auditory cue rates, and failure rate were evaluated during missions to keep a virtual avatar safe from a traffic accident in the VR program. The line bisection test and letter cancellation test were also evaluated.

RESULTS

The deviation angle, left-to-right reaction time ratio, left visual and auditory cue rates and left failure rate in the VR program showed significant differences between the two groups (P < 0.05). Depending on the direction of approach of the virtual car, the left parameters were significantly higher than the right parameters in the neglect group (P < 0.05). In the neglect group, the line bisection test correlated significantly with the deviation angle (P < 0.05). None of the other virtual reality parameters significantly correlated with the paper and pencil tests.

CONCLUSION

Post-stroke neglect in the extrapersonal space can be easily and safely detected and measured using our three-dimensional immersive virtual street crossing program.

Carboxylic acid functionalized multi-walled carbon nanotube-adsorption onto poly(methyl methacrylate) microspheres

We prepared multi-walled carbon nanotube (MWNT) coated polymeric microspheres i.e., carboxylic acid functionalized MWNT (c-MWNT) adsorbed onto poly(methyl methacrylate) (PMMA) microspheres. Initially, the MWNT was functionalized with carboxylic acid functional group and PMMA microspheres were synthesized via a dispersion polymerization method separately. The c-MWNT/PMMA microspheres were then fabricated by blending technique i.e., simple mixing of c-MWNT and PMMA microspheres dispersed solutions under ultrasonication. Surface morphologies of the c-MWNT-adsorbed PMMA microspheres were observed using scanning electron microscopy (SEM). In addition, c-MWNT/PMMA microsphere suspension dispersed in silicone oil showed typical electrorheological characteristics of fibril structure under an applied electric field.

Oxaliplatin combined with leucovorin plus 5-FU (FOLFOX) in patients with advanced/metastatic biliary tract carcinoma

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Background: Biliary tract carcinoma is often diagnosed at advanced stage, with median survival rarely exceeding 6 months. There is currently no established palliative standard of care. A phase II trial was conducted to study a FOLFOX regimen as first- or second- line therapy in biliary tract carcinoma. Methods: Patients with unresectable or metastatic intrahepatic or extrahepatic biliary duct carcinoma and gallbladder carcinoma were enrolled. Eligible patients were between 18 and 75 years of age and had histologically confirmed, measurable adenocarcinoma. Patients were stratified according to prior chemotherapy(6) and no prior chemotherapy(15). Treatment consisted of intravenous oxaliplatin (100mg/m2) as a 2 hours infusion on day 1 followed by leucovorin 100mg/m2 on day1 and 5-FU 1000∼1200mg/m2 as a 24 hours infusion on day 1,2. Treatment was repeated every 3 weeks for up to 6 cycles. Tumor response, survival and safety were determined Results: A total of 21 patients were evaluable;12 men and 9 women with a median age of 57(range 37–71). Tumor sites were: intrahepatic (n=7) and extrahepatic biliary duct (n=9); gallbladder (n=4); and ampulla (n=1). Total 115 cycles were administered (median 5 cycles, range 2∼12). According to RECIST criteria, partial response 3(14.3%), stable disease 10(47.7%) and disease progression.8(38%). The overall response rate with and without prior chemotherapy were 0%(0/6) and 20%(3/15), respectively. In patients without prior chemotherapy (15), median progression-free-survival and overall survival were 6.6(range, 1.2∼12.8) and 8.7(range, 3.7∼19.3) months. Grade 1–2 neurotoxicity, fatigue, diarrhea, anorexia, nausea were common. Grade 3 neutropenia and thrombocytopenia occurred in 23% and 4.7% of the patients respectively. There was no treatment related death. Conclusions: FOLFOX should be considered an active and well tolerated first-line combination chemotherapy regimen for patients with advanced/metastatic biliary tract carcinoma.

No significant financial relationships to disclose.

The role of stigma in reasons for HIV disclosure and non-disclosure to children

This study examined how stigma may impact HIV-positive women's disclosure to their children. Participants included HIV-infected women recruited from AIDS service organizations located in large midwestern cities. Using a questionnaire and guided interview, quantitative data were obtained regarding perceived HIV-related stigma and rates of maternal disclosure to children aged 5-18. According to the Kruskal-Wallis test, comparison between the disclosure groups showed non-significant differences in the total score of HIV stigma (chi(2)=0.518 with df = 2, p=0.77).

Application of extended single-reaction multiplex polymerase chain reaction for toxin typing of Staphylococcus aureus isolates in South Korea

The extended single-reaction multiplex PCR (esr-mPCR) developed in this study to detect staphylococcal enterotoxins (SEs), including SEA, SEB, SEC, SED, SEE, SEH, SEI, and SEJ, requires fewer sets of primers than other conventional multiplex PCRs and can be used to detect newly identified staphylococcal enterotoxins SEs more readily. Esr-mPCR analysis of 141 isolates of Staphylococcus aureus obtained from abattoir and livestock product samples revealed that 27 of the S. aureus isolates were toxigenic, and two were 2 multitoxigenic isolates. The most prevalent SE type was SEI followed by SEA and SEH. In addition, we investigated the clonal relatedness of toxigenic S. aureus isolates by arbitrarily primed PCR (AP-PCR). AP-PCR analysis of toxigenic S. aureus isolates revealed that the discriminatory power of AP-PCR was 9 (D=0.81), 8 (D=0.77), and 10 types (D=0.83) with primers AP1, ERIC2, and AP7, respectively. The combination of three each AP-PCR result could rearrange toxigenic S. aureus isolates into 10 types and five subtypes, with the D-value of 0.92. Interestingly, our data showed that toxigenic S. aureus isolates from different sources had different fingerprinting patterns although some of them carried the same types of SE genes. These data suggest that combinations of esr-mPCR and AP-PCR can provide a powerful approach for epidemiological investigation of toxigenic S. aureus isolates.

Expression of Na+/H+ and HCO3−-dependent transporters in Na+/H+ exchanger isoform 1 null mutant mouse brain

Acid-base transporters, such as the sodium-hydrogen exchangers (NHEs) and bicarbonate-dependent transporters, play an important role in the regulation of intracellular pH (pH(i)) in the CNS. Previous studies from our laboratory have shown that the absence of the major NHE isoform 1 (NHE1) reduced the steady-state pH(i) and recovery rate from an acid load in the hippocampal neurons not only in HEPES but also in HCO(3)(-) solutions (Yao et al., 1999). The purpose of the current study was to determine whether the NHE1 null mutation affects the expression of pH-regulatory transporters in the mouse CNS. Immunoblotting and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) were performed to examine the protein and mRNA levels of NHE1-4, electrogenic sodium-bicarbonate cotransporter 1 variants (NBCe1), and brain-specific anion exchanger 3 (AE3) in four brain regions (cerebral cortex, hippocampus, cerebellum and brainstem-diencephalon). NHE1 null mutant mice were compared with their wild type controls at the average age of approximately 4 weeks. Our results revealed that the NHE1 null mutation caused a significant increase in NHE3 in the cerebellum (84% for protein, 105% for mRNA), an increase in NBCe1 expression in the brainstem-diencephalon (approximately 40-50% for protein, 9-15% for mRNA), as well as a decrease in AE3 in the hippocampus (approximately 60% for protein, 24% for mRNA). We conclude that the NHE1 null mutation does alter the expression of other membrane transporters at both protein and mRNA levels. The alteration is region-specific. An increase in acid extruders (e.g. NHE3) and a decrease in acid loaders (e.g. AE3) suggest that there are some compensatory mechanisms that occur in NHE1 null mutant mice.

Antimicrobial performance of alkaline ionic fluid (GC-100X) and its ability to remove Escherichia coli O157:H7 from the surface of tomatoes

An efficacy test of GC-100X, a noncorrosive alkaline ionic fluid (pH 12) composed of free radicals and supplemented with xylitol, was carried out against six major foodborne pathogens-Staphylococcus aureus FRI 913, Salmonella enterica serovar Enteritidis ATCC 13076, S. enterica serovar Typhimurium DT104 Korean isolate, Vibrio parahaemolyticus ATCC 17803, Escherichia coli O157:H7 ATCC 43894, and Pseudomonas aeruginosa KCTC 1637-at three different temperatures (4, 25, and 36 degrees C) with or without organic load (2% yeast extract). Results revealed a more than 4-log10 (CFU/ml) reduction (1.0 x 10(4) CFU/ml reduction) against all pathogens reacted at 37 degrees C for 3 h in the absence of organic material. GC-100X solution diluted with an equal volume of distilled or standard hard water (300 ppm CaCO3) showed effective bactericidal activity, particularly against gram-negative bacteria. Washing efficacy of GC-100X solution was compared against E. coli O157:H7 on cherry tomato surfaces with those of a commercially used detergent and chlorine water (100 ppm). Viable cell counts of E. coli O157:H7 that had penetrated to the cores of tomatoes after sanitizing treatment revealed that GC-100X stock and its 5% diluted solutions had similar washing effects to 100-ppm chlorine water and were more effective than the other kitchen detergent. These results indicate that GC-100X has good bactericidal and sanitizing activities and is useful as a new sanitizer for food safety and kitchen hygiene.

Opposite role of Ras in tumor necrosis factor-alpha-induced cell cycle regulation: competition for Raf kinase

Ras, a well-known oncogene, induces cell cycle stimulation through the Raf/Erk pathway and leads to cellular transformation, accompanied by other oncogenes such as c-myc and viral oncogenic protein. Here we suggest the interfering role of Ras in tumor necrosis factor (TNF)-alpha-induced cell cycle regulation. In TSU-Pr1 and T24 (oncogenic Ras cell lines), TNF-alpha suppresses cell cycle progression without induction of apoptosis, whereas AGS (wild-type Ras) is stimulated in its cell cycle by TNF-alpha coupled with activation of Erk. However, in TSU-Pr1 and T24, TNF-alpha leads to dephosphorylation of Erk1/2. Inhibition or activation of Ras can restore or convert TNF-alpha-induced cell cycle regulation in the cell lines containing the oncogenic Ras (TSU-Pr1 and T24) or AGS, respectively. Regulation of Erk also shows the coincidental pattern. We suggest the competition between the Ras pathway and TNF signaling for the binding to Raf, a common downstream target, as the cause of such reciprocal response, based on co-immunoprecipitation (co-IP) with antibodies against Raf and Ras or cellular Flice-inhibitory protein (c-FLIP), which have been recently identified upstream of Raf in death-ligand-induced cell cycle stimulation. Overexpression of Raf in TSU-Pr1, to reduce the competition, overcomes TNF-induced cell cycle arrest, also supporting our hypotheses.

Treatment of vitiligo with suction epidermal grafting by the use of an ultrapulse CO2 laser with a computerized pattern generator

BACKGROUND

Laser ablation is used to remove the recipient epidermis in the suction epidermal grafting in vitiligo surgery.

OBJECTIVE

To evaluate the effectiveness and safety of a suction epidermal grafting method after the removal of the epidermis by the use of the Ultrapulse CO2 laser with a computerized pattern generator.

METHODS

Eleven patients with 34 lesions of refractory stable vitiligo were studied.

RESULTS

Of the 34 lesion sites, excellent repigmentation was seen in 30 and the other 4 had good repigmentation. No complications occurred.

CONCLUSION

The Ultrapulse CO2 laser is particularly well suited for deepithelialization in vitiligo surgery.

Optimization of facilitation related to threshold in transcranial magnetic stimulation

OBJECTIVES

To attain the standardized procedure for optimal facilitation, we analyzed motor-evoked potential (MEP) responses to the degree of voluntary contraction and stimulus intensity.

METHODS

Fifteen normal subjects were included. MEPs were elicited at thenar muscles during rest and at gradual voluntary contraction (MVC), using 10, 30, and 50% of MVC. During rest and each contraction, the excitability threshold at rest (RET) and at contraction (CET) were determined. Consecutive stimuli were applied, with the intensity of ratio increments (110-150% of ET).

RESULTS

The RET showed a remarkable decrease after contraction. Shortening of latency reached a saturation level at 10% of MVC. Amplitude reached a saturation level at 30% of MVC with 62.7+/-8.5% of the maximum output, which is equal to 140% intensity of CET, and 110% of RET. The MEP amplitudes at rest and at 10% MVC were influenced by their ETs, but those measured above 30% of MVC were not related.

CONCLUSIONS

The procedure recommended for optimal facilitation is as follows: to achieve minimal latency of MEPs, a minimal contraction (10% of MVC) with RET intensity is sufficient and for maximal amplitude, a moderate contraction (30% of MVC) with 110% of RET intensity is adequate.

Transplacental transfer and age-related levels of serum IgG antibodies to the capsular polysaccharides of Streptococcus pneumoniae types 14 and 19 in Korea

Little is known about the prevalence of naturally acquired IgG antibodies to the capsular polysaccharides of Streptococcus pneumoniae (pneumococcal IgG) in Korea. In the present study, we investigated transplacental transfer and age-related levels of pneumococcal IgG to provide background seroepidemiologic data for S. pneumoniae in Korea. One hundred thirty eight sera were assayed by ELISA for IgG to pneumococcal polysaccharide capsular serotypes 14 and 19, the predominant serotypes for under 15 yr of age in Korea. The subjects were divided into 7 subgroups according to age. The cord/maternal geometric mean titer of pneumococcal were 4.47+/-5.88/5.21 +/- 5.88 for serotype 14, and 4.68 +/- 5.55/6.55 +/- 6.92 for serotype 1 9 (mean +/- standard deviation, microg/mL). After birth, the geometric mean titers of pneumococcal IgG for serotypes 14 and 19 expressed in microg/mL were 1.18+/-2.12 and 1.41+/-2.17 in the 0-6 months group, 0.27+/-0.19 and 0.69+/-0.93 in 7-12 months, 0.21+/-0.22 and 0.64+/-1.32 in 1-2 yr, 0.69+/-0.78 and 2.65+/-2.46 in 3-6 yr, 2.52+/-2.72 and 8.29+/-4.24 in 7-10 yr, respectively. In conclusion, reduced transplacental transfer and very low serum concentrations of pneumococcal IgG may contribute to the susceptibility of neonates, infants, and young children to S. pneumoniae infection.

Analysis of expressed sequence tags from Brassica rapa L. ssp. pekinensis

Non-redundant expressed sequence tags (ESTs) were generated from six different organs at various developmental stages of Chinese cabbage, Brassica rapa L. ssp. pekinensis. Of the 1,295 ESTs, 915 (71%) showed significantly high homology in nucleotide or deduced amino acid sequences with other sequences deposited in databases, while 380 did not show similarity to any sequences. Briefly, 598 ESTs matched with proteins of identified biological function, 177 with hypothetical proteins or non-annotated Arabidopsis genome sequences, and 140 with other ESTs. About 82% of the top-scored matching sequences were from Arabidopsis or Brassica, but overall 558 (43%) ESTs matched with Arabidopsis ESTs at the nucleotide sequence level. This observation strongly supports the idea that gene-expression profiles of Chinese cabbage differ from that of Arabidopsis, despite their genome structures being similar to each other. Moreover, sequence analyses of 21 Brassica ESTs revealed that their primary structure is different from those of corresponding annotated sequences of Arabidopsis genes. Our data suggest that direct prediction of Brassica gene expression pattern based on the information from Arabidopsis genome research has some limitations. Thus, information obtained from the Brassica EST study is useful not only for understanding of unique developmental processes of the plant, but also for the study of Arabidopsis genome structure.

Detection of human herpesvirus 8 DNA in pemphigus and chronic blistering skin diseases

Increased incidences of Kaposi's sarcoma and lymphoid malignancies have been observed in patients with pemphigus, and the human herpesvirus 8 (HHV-8) is very strongly associated with these tumors. Because the virus may be one of the triggering factors of pemphigus, we undertook this study to screen for the presence of HHV-8 in chronic blistering skin diseases including pemphigus. A total of 45 paraffin-embedded specimens were studied using nested polymerase chain reaction (PCR) with primers to amplify a 160-base pair HHV-8 fragment. HHV-8 DNA could be detected in 7 of 9 patients with pemphigus vulagris, and 1 of 2 with pemphigus foliaceus. All specimens of other blistering skin diseases were negative for HHV-8. On sequencing PCR products, the sequences were almost identical with the prototypic sequence for HHV-8, and a few base- pair substitutions at 1086C-T and 1139A-C were detected. The results of our study suggests that HHV-8 might have trophism for pemphigus lesions. Further studies including comparison of HHV-8 DNA load in both lesional and normal skin in the same patient, serological and animal studies would be helpful to study the relationship between HHV-8 and pemphigus.

Characterization of a bifunctional enzyme fusion of trehalose-6-phosphate synthetase and trehalose-6-phosphate phosphatase of Escherichia coli

To test the effect of the physical proximity of two enzymes catalyzing sequential reactions, a bifunctional fusion enzyme, TPSP, was constructed by fusing the Escherichia coli genes for trehalose-6-phosphate (T6P) synthetase (TPS) and trehalose-6-phosphate phosphatase (TPP). TPSP catalyzes the sequential reaction in which T6P is formed and then dephosphorylated, leading to the synthesis of trehalose. The fused chimeric gene was overexpressed in E. coli and purified to near homogeneity; its molecular weight was 88,300, as expected. The K(m) values of the TPSP fusion enzyme for the sequential overall reaction from UDP-glucose and glucose 6-phosphate to trehalose were smaller than those of an equimolar mixture of TPS and TPP (TPS/TPP). However, the k(cat) values of TPSP were similar to those of TPS/TPP, resulting in a 3.5- to 4.0-fold increase in the catalytic efficiency (k(cat)/K(m)). The K(m) and k(cat) values of TPSP and TPP for the phosphatase reaction from T6P to trehalose were quite similar. This suggests that the increased catalytic efficiency results from the proximity of TPS and TPP in the TPSP fusion enzyme. The thermal stability of the TPSP fusion enzyme was quite similar to that of the TPS/TPP mixture, suggesting that the structure of each enzyme moiety in TPSP is unperturbed by intramolecular constraint. These results clearly demonstrate that the bifunctional fusion enzyme TPSP catalyzing sequential reactions has kinetic advantages over a mixture of both enzymes (TPS and TPP). These results are also supported by the in vivo accumulation of up to 0.48 mg of trehalose per g of cells after isopropyl-beta-D-thiogalactopyranoside treatment of cells harboring the construct encoding TPSP.