Abnormal functional connectivity of the reward network is associated with social communication impairments in autism spectrum disorder: A large-scale multi-site resting-state fMRI study

BACKGROUND

The social motivation hypothesis proposes that the social deficits of autism spectrum disorder (ASD) are related to reward system dysfunction. However, functional connectivity (FC) patterns of the reward network in ASD have not been systematically explored yet.

METHODS

The reward network was defined as eight regions of interest (ROIs) per hemisphere, including the nucleus accumbens (NAc), caudate, putamen, anterior cingulate cortex (ACC), ventromedial prefrontal cortex (vmPFC), orbitofrontal cortex (OFC), amygdala, and insula. We computed both the ROI-wise resting-state FC and seed-based whole-brain FC in 298 ASD participants and 348 typically developing (TD) controls from the Autism Brain Imaging Data Exchange I dataset. Two-sample t-tests were applied to obtain the aberrant FCs. Then, the association between aberrant FCs and clinical symptoms was assessed with Pearson's correlation or Spearman's correlation. In addition, Neurosynth Image Decoder was used to generate word clouds verifying the cognitive functions of the aberrant pathways. Furthermore, a three-way multivariate analysis of variance (MANOVA) was conducted to examine the effects of gender, subtype and age on the atypical FCs.

RESULTS

For the within network analysis, the left ACC showed weaker FCs with both the right amygdala and left NAc in ASD compared with TD, which were negatively correlated with the Autism Diagnostic Observation Schedule (ADOS) total scores and Social Responsiveness Scale (SRS) total scores respectively. For the whole-brain analysis, weaker FC (i.e., FC between the left vmPFC and left calcarine gyrus, and between the right vmPFC and left precuneus) accompanied by stronger FC (i.e., FC between the left caudate and right insula) were exhibited in ASD relative to TD, which were positively associated with the SRS motivation scores. Additionally, we detected the main effect of age on FC between the left vmPFC and left calcarine gyrus, of subtype on FC between the right vmPFC and left precuneus, of age and age-by-gender interaction on FC between the left caudate and right insula.

CONCLUSIONS

Our findings highlight the crucial role of abnormal FC patterns of the reward network in the core social deficits of ASD, which have the potential to reveal new biomarkers for ASD.

"Primer shot" fractionation with an early treatment break is theoretically superior to consecutive weekday fractionation schemes for early-stage non-small cell lung cancer

PURPOSE

Radiotherapy is traditionally given in equally spaced weekday fractions. We hypothesize that heterogeneous interfraction intervals can increase radiosensitivity via reoxygenation. Through modeling, we investigate whether this minimizes local failures and toxicity for early-stage non-small cell lung cancer (NSCLC).

METHODS

Previously, a tumor dose-response model based on resource competition and cell-cycle-dependent radiosensitivity accurately predicted local failure rates for early-stage NSCLC cohorts. Here, the model mathematically determined non-uniform inter-fraction intervals minimizing local failures at similar normal tissue toxicity risk, i.e., iso-BED3 (iso-NTCP) for fractionation schemes 18Gyx3, 12Gyx4, 10Gyx5, 7.5Gyx8, 5Gyx12, 4Gyx15. Next, we used these optimized schedules to reduce toxicity risk (BED3) while maintaining stable local failures (TCP).

RESULTS

Optimal schedules consistently favored a "primer shot" fraction followed by a 2-week break, allowing tumor reoxygenation. Increasing or decreasing the assumed baseline hypoxia extended or shortened this optimal break by up to one week. Fraction sizes of 7.5 Gy and up required a single primer shot, while smaller fractions needed one or two extra fractions for full reoxygenation. The optimized schedules, versus consecutive weekday fractionation, predicted absolute LF reductions of 4.6%-7.4%, except for the already optimal LF rate seen for 18Gyx3. Primer shot schedules could also reduce BED3 at iso-TCP with the biggest improvements for the shortest schedules (94.6Gy reduction for 18Gyx3).

CONCLUSION

A validated simulation model clearly supports non-standard "primer shot" fractionation, reducing the impact of hypoxia-induced radioresistance. A limitation of this study is that primer-shot fractionation is outside prior clinical experience and therefore will require clinical studies for definitive testing.

Nomogram to Predict Risk of Early Mortality Following Definitive or Adjuvant Radiation and Systemic Therapy for Head and Neck Cancer

PURPOSE/OBJECTIVE(S)

Tools to predict individual patient risk for early mortality in head and neck cancer patients receiving chemoradiation are lacking. We sought to create a nomogram to predict individual risk of early mortality, which may help identify patients who require interventions to prevent early death.

MATERIALS/METHODS

We included patients in the National Cancer Database with non-metastatic squamous cell carcinoma of the head and neck who received radiation and systemic therapy between 2004 and 2017 in either the definitive or adjuvant setting. Covariates analyzed in the cohort include race, gender, income, age, T and N category, tumor site, insurance type, facility type, urban or rural environment, radiation modality, and comorbidity. Early mortality was defined as any death less than 90 days after the beginning of radiation. Chi-squared analysis was used for all categorical covariates and t-tests were used for continuous variables to test for associations with early mortality. Multivariable logistic regression was used to assess the relationship between covariates and early mortality. Nomograms to predict the risk of early death were created for both the definitive and adjuvant settings.

RESULTS

The final cohorts included 84,563 patients in the definitive group and 18,514 patients in the adjuvant group. Rates of early mortality were 3.5% (95% CI 3.4-3.7%) and 2.2% (95% CI 1.9-2.4%) in the definitive and adjuvant cohorts, respectively. Patients above the age of 70 had an early mortality rate of 7.8% (95% CI 7.3-8.2%) in the definitive group and 4.4% (95% CI 3.6-5.4%) in the adjuvant group. In the multivariable analysis, age, comorbidity, T and N category, and tumor site were associated with early mortality in both cohorts (p<0.05 for all); while in the definitive group, radiation type, year of diagnosis, and insurance status were also statistically significant (p<0.05). In both cohorts, nomograms were created to predict the risk of early mortality that included age, comorbidity, T and N category and tumor site. The nomogram including age, comorbidity, T and N category and tumor site performed better than age alone at predicting early mortality (AUC for definitive group: 0.70 vs 0.66; AUC for adjuvant group: 0.71 vs 0.61).

CONCLUSION

Nomograms including age, comorbidity, T and N category and tumor site were developed to predict the risk of early death following definitive or adjuvant chemoradiation.

Pencil Beam Scanning Proton Stereotactic Body Radiation Therapy (SBRT): A Robust Single Institution Experience

PURPOSE/OBJECTIVE(S)

To describe the feasibility of treating a complex and diverse group of patients using pencil beam scanning (PBS) proton stereotactic body radiation therapy (SBRT: 5 or fewer fractions, with a fraction size of at least 5 Gy).

MATERIALS/METHODS

Our center treats on average 105-120 PBS proton treatments daily, of which 9.5% of treatment courses are proton SBRT. Statistics of disease sites, treatment planning parameters (target volume, prescriptions, number of fields, SFO vs. MFO), and treatment efficiencies (scheduled time slots, actual treatment time) are presented for 305 consecutive SBRT patients receiving 1507 fractions in the past three years. Thermoplastic masks or Vacuum-lock bags are used to immobilize SBRT patients and index the patients' treatment position. Imaging guidance of orthogonal kV images and volumetric cone-beam CT is routinely used for patient setup.

RESULTS

SBRT patients are grouped based on the target locations: pelvis (31%), liver (17%), thoracic (13%), spine (8%), abdominal (8%), brain (7%), non-spine bone (7%), ocular (6%), and head and neck (2%). Only 112 patients (37%) were receiving their 1st RT course, whereas 113 (37%) had one prior in-field RT course, and 80 (26%) had multiple prior in-field RT courses. The median [IQR] target volume was 65.4 [29.3, 168] cc (range: 0.3-2475 cc). 72% of cases were planned with SFO and 28% with MFO. On average, 3.76 fields (range: 2 to 12) were planned for each treatment. 44% of the treatments were planned with three or fewer fields, and 10% received more than five fields, most of which involved repainting for moving targets. Over 97% of treatments were delivered in 5 fractions, with ∼3% delivered in 3 fractions. The median [IQR] prescription per treatment was 8 [7, 10] Gy (range: 5-18 Gy per treatment). 85% (84%) of the SBRT treatments were scheduled (delivered) in a 45-minute or shorter slot, and 6% (7%) of treatments were scheduled (delivered) in over a one-hour slot, most commonly for multiple isocenter treatments. 93% of treatments were delivered within 15 minutes of the planned treatment time or shorter. Deep-inspiration breath-hold (DIBH) was applied to 45% of liver SBRT cases, with the remaining 55% planned on 4D CT with (14%) or without (86%) abdominal compression. DIBH was applied in 13% of lung SBRT cases. The application of other motion mitigation approaches, such as volumetric repainting, was determined by the target motion amplitude and whether the patient could tolerate DIBH.

CONCLUSION

In the most diverse and largest proton SBRT experience delivered in the world over the past 3 years, over 300 patients were treated, demonstrating the feasibility and efficiency of delivering proton SBRT in a very busy center. The planning and treatment parameter statistics reported serve as a helpful reference for the proton community.

Radiotherapy (RT) for Cutaneous Adnexal Carcinoma (CAC): 49 Patients Treated at a Single Institution Over 2 Decades

PURPOSE/OBJECTIVE(S)

Cutaneous adnexal carcinomas (CACs) are a heterogenous group of rare skin cancers. Management strategies are extrapolated from the treatment of more common skin cancers, and case series describing patients treated with radiotherapy (RT) for CAC are limited to <15 patients. We reviewed our institutional experience to better understand the characteristics and outcomes of patients with CAC treated with RT.

MATERIALS/METHODS

Patients diagnosed with CAC and treated RT from 2000-2020 were identified using the following keywords: adnexal, microcystic, apocrine, eccrine, sebaceous, sweat gland, syringoma, mucinous, tubular, porocarcinoma, hidradenocarcinoma, and cylindrocarcinoma. Patient, cancer, and treatment characteristics were assessed by retrospective record review. Time to overall survival (OS), locoregional recurrence (LRR), distant metastasis (DM), and progression free survival (PFS) were evaluated using Kaplan-Meier methods.

RESULTS

Forty-nine patients with a median age of 65 years (IQR 53-82) were identified. Most were white (90%) men (59%) harboring tumors on the head and neck (80%). The most common subtypes of CAC were adnexal adenocarcinoma (39%), sebaceous carcinoma (35%) and microcystic adnexal carcinoma (10%). Patients were treated for de novo cancer (n = 35) or after recurrence (n = 14). Among de novo cases, 9 (26%) were treated with definitive RT, 22 (63%) were treated with surgery and adjuvant RT, and 4 (11%) with palliative RT. Per UICC system, de novo stage at time of RT was I in 2 (6%), II in 9 (26%), III in 12 (34%), IVA in 10 (29%), and IVB in 2 (6%). Median OS was 44 months and median follow-up of surviving patients was 41 months (IQR 17-75). De novo patients treated with definitive RT received a median dose of 70 Gy (IQR 60-73 Gy) and experienced 2-year rates of PFS, LRR, and DM of 30%, 55%, and 40%, respectively. All LRR events occurred within the irradiated volume. De novo patients treated with surgery and adjuvant RT received a median dose of 60 Gy (IQR 60-64 Gy) and experienced 2-year rates of PFS, LRR, and DM of 77%, 13%, and 10%, respectively. All LRR events occurred outside the irradiated volume. Among patients treated at recurrence, most (93%) underwent surgery and adjuvant RT. Per UICC system, their stage at time of RT was II in 2 (15.4%), III in 4 (30.8%), and IVA in 7 (53.8%). Recurrent patients treated with surgery and adjuvant RT received a median dose of 60 Gy (IQR 60-66 Gy) and experienced 2-year rates of PFS, LRR, and DM of 30%, 58%, and 29%, respectively. Three of 4 evaluable patients treated with palliative RT exhibited stable disease or tumor response.

CONCLUSION

In the largest single institution analysis to date, RT was primarily used for CAC patients as an adjuvant treatment. LRR was less frequent and less likely to occur within irradiated volume in patients selected for surgery and adjuvant RT than those selected for definitive RT or at time of recurrence.

Impact of Surveillance Imaging in Patients with HPV-Associated Oropharyngeal Carcinomas Treated with Definitive Radiation and Chemotherapy

PURPOSE/OBJECTIVE(S)

Post-treatment surveillance imaging for HPV-associated oropharyngeal carcinomas (OPCs) differs among physicians and institutions. Surveillance imaging can detect disease progression earlier, but can also contribute to anxiety and cost, without proven disease-free or survival benefit. We sought to determine the number of surveillance scans needed to detect a recurrence in patients with HPV-associated OPCs.

MATERIALS/METHODS

We included consecutive patients with locally advanced HPV-associated OPC that received definitive concurrent chemoradiotherapy (CRT) with 70 Gy between March 1, 2017 to July 31, 2019. First post-treatment scans were defined as the first scans following the end of CRT. Surveillance scans were defined as body FDG PET/CTs, neck or chest CTs, and neck MRIs taken after the first post-treatment scans showed no evidence of disease. Any scans ordered to follow suspicious lesions on first post-treatment scans were not counted as surveillance scans. Recurrences were classified as detected by first post-treatment scans, surveillance scans, clinical exam, or incidental findings. The number of surveillance scans needed to detect 1 recurrence was determined by dividing the number of surveillance scans by the number of recurrences detected by surveillance scans.

RESULTS

There were a total of 275 patients with median follow-up of 39.8 months (Interquartile Range (IQR), 34.9-47.8). Surveillance scans were first taken at a median of 12.1 months (IQR, 9.2-16) post-CRT. There were 27 (9.8%) patients who had a recurrence: 7 (2.5%) had locoregional recurrence (LR), 19 (6.9%) had distant metastasis (DM), and 1 (0.4%) had both LR and DM. LR was detected at a median of 5.8 months (IQR, 3.4-10.6) post-CRT and DM was detected at a median of 9.5 months (IQR, 4.8-14.3) post-CRT. Of all recurrences, 11/27 (40.7%) were first post-treatment scan detected, 10 (37.0%) were surveillance scan detected, 5 (18.5%) were clinical exam detected, and 1 (3.7%) was incidentally detected on lung cancer screening. Four (50%) LRs were first post-treatment detected (median time to detection, MTD: 4.2 months), 3 (37.5%) were clinical exam detected (MTD: 6.7 months), and 1 (12.5%) was surveillance detected (MTD: 9.0 months). For DM, 9 (45%) were surveillance detected (MTD: 12.7 months), 8 (40%) were first post-treatment detected (MTD: 4.1 months), 2 (10%) were clinical exam detected (MTD: 18.9 months), and 1 (5%) was incidentally detected (MTD: 12.1 months). A total of 702 surveillance scans were taken during the follow-up period. The number of surveillance scans needed to detect 1 LR/DM was 71 overall, 50 within 2 years and 254 beyond 2 years from CRT.

CONCLUSION

First post treatment scans detect most recurrences for HPV-associated OPC. A high burden of surveillance scans is needed to detect one recurrence, especially beyond 2 years from CRT.

A novel machine learning approach to shorten depression risk assessment for convenient uses

BACKGROUND

Depression is a mental disorder affecting many people worldwide which has been exacerbated by the current pandemic. There is an urgent need for a reliable yet short scale for individuals to self-assess the risk of depression conveniently and rapidly on a regular basis.

METHODS

We obtained a dataset of responses to the Depression, Anxiety, and Stress questionnaire (DASS-42) from a large sample of individuals worldwide (N = 31,715). With this dataset, important items from the questionnaire were extracted by applying feature selection techniques. Then, using the most important features, various machine learning algorithms were trained, tested, and validated in predicting depression status.

RESULTS

This study revealed that only seven items are needed to predict depression status with at least 90 % accuracy of the original full scale. This can be achieved through the Stacked Generalization Ensemble learning method of multiple models. The trained machine learning models from the best algorithm were then implemented as an online Depression Rapid Assessment tool, which allows the user to evaluate their current depression status conveniently and quickly (about 1 min).

LIMITATIONS

The sample size of the present study is still relatively small and has biases toward certain demographics (e.g., mostly young, Asian, and female). Further, memory issues with Stacked Generalization Ensemble prevent it from being trained in the same way as the other algorithm.

CONCLUSION

It is possible to produce very short assessments that approximate the accuracy of the full scale for convenient and rapid self-assessment of depression risks.

Increased salivary syndecan-1 level is associated with salivary gland function and inflammation in patients with Sjögren's syndrome

Objectives: Syndecan-1 (SDC-1), a transmembrane heparin sulphate proteoglycan predominantly expressed on epithelial cells, also exists in a soluble form through ectodomain shedding. SDC-1 expression and shedding may be modulated in the inflammatory milieu of primary Sjögren's syndrome (SS). We investigated SDC-1 expression in minor salivary glands (MSGs) and analysed the association between salivary or plasma levels of SDC-1 and clinical parameters in SS.Method: We measured salivary and plasma SDC-1 levels via an enzyme-linked immunosorbent assay and assessed the salivary flow rates (SFRs) in 70 patients with SS and 35 healthy subjects. Disease activity indices, serological markers, salivary gland scintigraphy, and MSG biopsy were evaluated in patients with SS.Results: SDC-1 expression was upregulated on ductal epithelial cells in inflamed salivary glands. Salivary SDC-1 levels in patients significantly exceeded those in healthy subjects [median (interquartile range) 49.0 (20.7-79.1) vs 3.7 (1.7-6.3) ng/mL, p < 0.001] and inversely correlated with SFRs (r = -0.358, p = 0.032) and ejection fractions of the parotid (r = -0.363, p = 0.027) and submandibular (r = -0.485, p = 0.002) glands in salivary gland scintigraphy. Plasma SDC-1 levels were significantly correlated with the EULAR Sjögren's Syndrome Disease Activity Index (r = 0.507, p < 0.001) and EULAR Sjögren's Syndrome Patient Reported Index (r = 0.267, p = 0.033). Focus scores were correlated with salivary SDC-1 levels (r = 0.551, p = 0.004).Conclusion: Salivary and plasma SDC-1 levels may constitute potential biomarkers for salivary gland function and disease activity, respectively, in SS.

Incidence and Distribution of the Pathogens Causing Central Nervous System Infections at the University Hospital of Korea

BACKGROUND

The pathogens involved in central nervous system (CNS) infections are various, such as viruses, bacteria, and fungi, so a syndromic approach can be required. In addition, since their rapid and accurate detection is very crucial, molecular diagnostics using cerebrospinal fluid is becoming the emerging standard method.

METHODS

The study was conducted retrospectively to identify the incidence and distribution patterns of the pathogens according to gender, age, season, and month and to analyze their codetection from August 2017 to July 2020. It was also conducted to investigate turn-around times (TATs) according to the detection method. The detection methods were FilmArray® Meningitis/Encephalitis (M/E) method (FilmArray), Cepheid® Xpert EV assay (Xpert), and Multiplex PCR method for five species of bacteria.

RESULTS

The overall incidence for at least one pathogen was 13.9% (346/2,496). The highest incidence was shown in age group 4 (3 - 6 years), with 27.4%. The detection rates by FilmArray, Xpert, and Multiplex PCR method were 39.8%, 41.7%, and 0.4%, respectively. Enterovirus (EV) showed the highest incidence rate, which accounted for 37.0%. The distribution of the pathogens according to the age groups were the highest in age group 4, with 47.5% (168/354), followed by 27.4% (97/354) in age group 5. Of the ten cases in which bacteria were detected, S. agalactiae accounted for 60.0% (6/10), most of which occurred in age group 1. E. coli K1, L. monocytogenes, and N. meningitidis were not detected. In the viral distribution, EV accounted for the highest proportion in all age groups. The overall proportion of EV accounted for 87.6% (310/354), followed by human parechovirus with 2.8% (10/354). The most commonly detected season was summer, comprising 75.1%. A total of eight cases of co-detection with two pathogens accounted for 1.6% (8/507) in FilmArray. In FilmArray, all TATs were found to be shorter than Xpert.

CONCLUSIONS

The information on the incidence and distribution patterns of the pathogens causing CNS infections and their rapid detection are critically important to clinicians in the management of immunocompromised patients, elderly, and children. The expeditious molecular diagnostics for these pathogens would be valuable in medical decisions by clinicians.

Incidence and Distribution of Respiratory Microorganisms Causing Acute Respiratory Infections at the University Hospital of Korea

BACKGROUND

Acute respiratory infection caused by respiratory microorganisms including various kinds of viruses and bacteria is the most common infectious disease. When managing patients, it is crucial to detect these microorganisms rapidly and monitor their occurrence and tendency. Recently, the methods of detecting them have been implemented by molecular diagnostics. The authors intended to investigate their incidence and distribution and identify the significance of the molecular diagnosis for their detection.

METHODS

The retrospective study was conducted to investigate the incidence and distribution of respiratory microorganisms according to the age, gender, month, season, and the detection method and to analyze their co-infections from July 2016 to December 2019. In addition, the four types of turn-around time (TAT) for each detec-tion method were also analyzed.

RESULTS

The overall incidence for at least one respiratory microorganism was 23.1% (3,645/15,808). The highest incidence was identified in age group 2 (1 - 3 months), 38.5%. The incidence rates by multiplex PCR using Anyplex and Allplex, FilmArray method, and influenza virus (flu) antigen detection test were 44.2% (718/1,625), 63.1% (1,198/1,899), and 14.1% (1,729/12,284), respectively. The overall incidence between male and female patients showed no statistically significant difference (p = 0.980), except for the flu antigen detection test (p = 0.000). Influenza A viruses (flu A) accounted for the highest percentage (34.9%), followed by rhinovirus/enterovirus (20.5%), RSV (12.8%), flu B (8.3%), and adenovirus (7.6%). These microorganisms showed characteristic distribution patterns according to season and month. Flu A and flu B predominated in winter and accounted for an increasing proportion as age increased according to the age groups. The overall co-infection rate was 22.5% (432/1,916). The average TATs of the FilmArray method were significantly much faster than multiplex PCR using Anyplex and Allplex (p = 0.000).

CONCLUSIONS

The information on the incidence and distribution of respiratory microorganisms and their expeditious detection are considered critical to the management of the elderly, immunocompromised patients, and children. The rapid molecular-based diagnosis of respiratory infections would be beneficial in medical decision and prevention of their propagation.

Types and Frequencies of Pre-Analytical Errors in the Clinical Laboratory at the University Hospital of Korea

BACKGROUND

The results of laboratory tests play a critical role in patient management, so the clinical laboratory is obligated to report accurate results. However, the pre-analytical phase, in which human factors are mainly involved, is clearly a vulnerable part of the laboratory process. This study was conducted to investigate and analyze pre-analytical errors. The author intended to reduce these errors by some measures in order to enhance the credibility of the laboratory.

METHODS

A retrospective study was conducted to identify the rates and the types and frequencies of pre-analytical errors in the laboratory and analyze them according to the departments of patients, the sections of the laboratory, and the wards of the hospital. The reasons for these errors were persistently identified and analyzed in order to make efforts to reduce the errors. The activities for quality improvement including education and training programs on the phlebotomy teams were also accomplished to reduce these errors.

RESULTS

The overall rate of pre-analytical errors was 0.40%. The rate of these errors significantly decreased from 0.44% in 2017 to 0.36% in 2018. In particular, the proportion of improper volume decreased from 46.1% in 2017 to 36.4% in 2018. The most common pre-analytical error was 'improper volume' (41.5%), followed by 'undue clotting' (32.8%). These errors were overwhelmingly more common in inpatients than in outpatients. The rate of these errors was the highest in stat section (1.95%).

CONCLUSIONS

Clinical laboratory should make efforts to reduce pre-analytical errors in order to report accurate and expeditious results. Reduction of these errors can be achieved through analyzing and correcting the reasons for them and education and training on the phlebotomy teams and, as a result, the credibility of the laboratory may also be enhanced.

Liquid culture enhances diagnosis of patients with milder forms of non-tuberculous mycobacterial lung disease

OBJECTIVE

To evaluate the proportion and clinical characteristics of patients with non-tuberculous mycobacteria (NTM) lung disease diagnosed based on positive culture results in liquid medium only.

METHODS

We reviewed the medical records of 978 patients diagnosed with NTM lung disease. All clinical samples were cultured in both solid and liquid media.

RESULTS

Of the 978 patients, 111 (11.3%) were culture-positive in liquid medium only (liquid culture group), and 867 (88.7%) (solid culture group) on solid medium, regardless of the culture results in liquid medium. At the time of diagnosis, the liquid culture group was less likely than the solid culture group to have haemoptysis (11.7% vs. 20.0%, P = 0.04), positive sputum smear for acid-fast bacilli (14.4% vs. 50.2%, P < 0.001) or the fibrocavitary form of NTM lung disease (3.6% vs. 14.6%, P = 0.001). During the median follow-up period of 28.9 months (interquartile range 19.1-41.6), the proportion of patients requiring antibiotic treatment was lower in the liquid culture group than in the solid culture group (44.1% vs. 61.6%, P < 0.001).

CONCLUSIONS

Liquid media culture is helpful in the diagnosis of patients with less severe forms of NTM lung disease.

TGF-β triggers rapid fibrillogenesis via a novel TβRII-dependent fibronectin-trafficking mechanism

There is increased recycling of soluble fibronectin from the cell surface for fibrillogenesis. This recycling is regulated by TGF-β in a transcription- and SMAD-independent manner via specific TβRII and integrin α5β1 interactions. The recycling of fibronectin is Rab11 dependent and is required for TGF-β–induced cell migration.

Fibronectin (FN) is a critical regulator of extracellular matrix (ECM) remodeling through its availability and stepwise polymerization for fibrillogenesis. Availability of FN is regulated by its synthesis and turnover, and fibrillogenesis is a multistep, integrin-dependent process essential for cell migration, proliferation, and tissue function. Transforming growth factor β (TGF-β) is an established regulator of ECM remodeling via transcriptional control of ECM proteins. Here we show that TGF-β, through increased FN trafficking in a transcription- and SMAD-independent manner, is a direct and rapid inducer of the fibrillogenesis required for TGF-β–induced cell migration. Whereas TGF-β signaling is dispensable for rapid fibrillogenesis, stable interactions between the cytoplasmic domain of the type II TGF-β receptor (TβRII) and the FN receptor (α5β1 integrin) are required. We find that, in response to TGF-β, cell surface–internalized FN is not degraded by the lysosome but instead undergoes recycling and incorporation into fibrils, a process dependent on TβRII. These findings are the first to show direct use of trafficked and recycled FN for fibrillogenesis, with a striking role for TGF-β in this process. Given the significant physiological consequences associated with FN availability and polymerization, our findings provide new insights into the regulation of fibrillogenesis for cellular homeostasis.

Empirical combination of a β-lactam to vancomycin may not improve outcomes of methicillin-susceptible Staphylococcus aureus bacteremia, compared to vancomycin monotherapy

To evaluate effect of empirical combination of a β-lactam to vancomycin and vancomycin monotherapy in Staphylococcus aureus bacteremia (MSSA-B), we conducted a retrospective cohort study. Electronic medical records of individuals who were diagnosed with MSSA-B between January 2005 and February 2015 at a tertiary care center were reviewed. Patients were classified into three groups according to empirical antibiotic regimen (BL group, β-lactam; VAN group, vancomycin; BV group, combination of β-lactam and vancomycin), and 30-day all-cause mortality of each group was compared. During the study period, 561 patients with MSSA-B were identified. After exclusion of 198 patients (36 with poly-microbial infection, 114 expired within 2 days, and 48 already received parenteral antibiotics) and a matching process, 46 patients for each group were included. Baseline characteristics were similar except for severity and comorbidity scores. The 30-day mortality for all three groups were not significantly different (BL 4.3%, VAN 6.5%, BV 8.7%; P = 0.909). In a multivariate analysis, type of empirical antibiotic regimen was not statistically associated with 30-day all-cause mortality. In comparison with the VAN group, the BV group yielded a HR of 0.579 (95% CI = 0.086-3.890, P = 0.574). Pitt bacteremia score was the only significant factor for mortality. The empirical combination of a β-lactam to vancomycin was not associated with lower mortality in treating MSSA-B, compared to vancomycin monotherapy.

Thermally robust and biomolecule-friendly room-temperature bonding for the fabrication of elastomer-plastic hybrid microdevices

Here, we introduce a simple and fast method for bonding a poly(dimethylsiloxane) (PDMS) silicone elastomer to different plastics. In this technique, surface modification and subsequent bonding processes are performed at room temperature. Furthermore, only one chemical is needed, and no surface oxidation step is necessary prior to bonding. This bonding method is particularly suitable for encapsulating biomolecules that are sensitive to external stimuli, such as heat or plasma treatment, and for embedding fracturable materials prior to the bonding step. Microchannel-fabricated PDMS was first oxidized by plasma treatment and reacted with aminosilane by forming strong siloxane bonds (Si-O-Si) at room temperature. Without the surface oxidation of the amine-terminated PDMS and plastic, the two heterogeneous substrates were brought into intimate physical contact and left at room temperature. Subsequently, aminolysis occurred, leading to the generation of a permanent seal via the formation of robust urethane bonds after only 5 min of assembling. Using this method, large-area (10 × 10 cm) bonding was successfully realized. The surface was characterized by contact angle measurements and X-ray photoelectron spectroscopy (XPS) analyses, and the bonding strength was analyzed by performing peel, delamination, leak, and burst tests. The bond strength of the PDMS-polycarbonate (PC) assembly was approximately 409 ± 6.6 kPa, and the assembly withstood the injection of a tremendous amount of liquid with the per-minute injection volume exceeding 2000 times its total internal volume. The thermal stability of the bonded microdevice was confirmed by performing a chamber-type multiplex polymerase chain reaction (PCR) of two major foodborne pathogens - Escherichia coli O157:H7 and Salmonella typhimurium - and assessing the possibility for on-site direct detection of PCR amplicons. This bonding method demonstrated high potential for the stable construction of closed microfluidic systems socketed with biomolecule-immobilized surfaces such as DNA, antibody, enzyme, peptide, and protein microarrays.

Changes in the Microbial Composition of Microbrewed Beer during the Process in the Actual Manufacturing Line

This study investigated changes in the microbial composition of microbrewed beer during the manufacturing processes and identified potential microbial hazards, effective critical quality control points, and potential contamination routes. Comprehensive quantitative (aerobic plate count, lactic acid bacteria, fungi, acetic acid bacteria, coliforms, and Bacillus cereus) and qualitative (Escherichia coli and eight foodborne pathogens) microbiological analyses were performed using samples of raw materials (malt and manufacturing water), semiprocessed products (saccharified wort, boiled wort, and samples taken during the fermentation and maturation process), and the final product obtained from three plants. The initial aerobic plate count and lactic acid bacteria counts in malt were 5.2 and 4.3 log CFU/g, respectively. These counts were reduced to undetectable levels by boiling but were present at 2.9 and 0.9 log CFU/ml in the final product. Fungi were initially present at 3.6 log CFU/g, although again, the microbes were eliminated by boiling; however, the level in the final product was 4.6 log CFU/ml. No E. coli or foodborne pathogens (except B. cereus) were detected. B. cereus was detected at all stages, although it was not present in the water or boiled wort (total detection rate ¼ 16.4%). Results suggest that boiling of the wort is an effective microbial control measure, but careful management of raw materials and implementation of effective control measures after boiling are needed to prevent contamination of the product after the boiling step. The results of this study may constitute useful and comprehensive information regarding the microbiological quality of microbrewed beer.

Clinical characteristics of Raoultella ornithinolytica bacteremia

PURPOSE

Raoultella ornithinolytica is not well known as a clinical pathogen. We performed a retrospective review of R. ornithinolytica bacteremia to investigate its clinical features, antimicrobial susceptibility, and overall patient outcomes.

METHODS

R. ornithinolytica bacteremia cases were collected from an electronic database of all cases of bacteremia over a 10-year period. Medical records were retrospectively reviewed. Demographic data, clinical information, the presence of underlying comorbidities, the results of antimicrobial susceptibility testing, and the antimicrobial regimen administered were investigated.

RESULTS

R. ornithinolytica was isolated from blood culture specimens in 16 cases. The majority of these patients had an underlying malignant condition of advanced stage (15 patients, 94 %). Seven of these patients had a solid tumor with lesions or metastases that extended to the bile duct or biliary tract. Neutropenic fever following hematologic stem cell transplantation was found in three cases. No resistance to piperacillin/tazobactam or imipenem was found. Four cases showed resistance to cefoxitin, while one of these cases showed resistance to multiple cephalosporins. In overall outcomes, seven patients (44 %) did not recover from the infection and subsequently expired.

CONCLUSIONS

R. ornithinolytica bacteremia occurs mainly in patients with underlying malignancies. The overall outcome was not favorable, despite favorable antimicrobial susceptibility test results. The findings of this study contradict those of other studies that demonstrated that infection from Raoultella species have good prognoses.

The evaluation of combined chemical and physical treatments on the reduction of resident microorganisms and Salmonella Typhimurium attached to chicken skin

This study was conducted to evaluate the efficacy of sodium hypochlorite (NaOCl, 0-200 mg/kg), thiamine dilauryl sulfate (TDS, 1,000 mg/kg), and ultrasound (37 kHz, 380 W) on reducing Salmonella Typhimurim, mesophilic aerobic bacteria (MAB), and coliforms on chicken skin. Chemical and physical treatments were applied for 5 min either singly or jointly, and Salmonella previously inoculated on chicken skin were quantitatively assessed using brilliant green agar, and the populations of MAB and coliforms in the native flora were enumerated using plate count agar and violet red bile agar, respectively. In the evaluation of bacterial attachment/detachment, chicken skin was quantitatively assessed for loosely, intermediately, and tightly attached bacteria. The treatment effects on bacteria detachment were also visualized using field emission scanning electron microscopy. In addition, color and textural properties of the skin after treatments were evaluated using a color difference meter and texture analyzer. Antimicrobial activity of NaOCl increased as the NaOCl concentration was increased, especially for loosely attached cells. The combination of 200 mg/kg NaOCl and ultrasound (NaOCl/ultrasound) significant reduced loosely, intermediately, and tightly attached bacteria populations by 0.75 to 0.47, 0.43 to 0.41, and 0.83 to 0.54 log cfu/g for MAB, coliforms, and Salmonella Typhimurium, respectively. However, the combination of NaOCl and TDS (NaOCl/TDS) did not sufficiently reduce those cells on chicken skins, except for loosely attached MAB and coliforms. The NaOCl/ultrasound combination produced a higher reduction in numbers of inoculated and native bacteria flora than any single application, with no negative effect on skin color or texture. Generally, the loosely attached bacteria were less resistant to the chemical and physical treatments than the intermediately and tightly attached bacteria in chicken skin, presumably due to their location in deeper skin layer and crevices. Further research is needed to investigate how the intermediately and tightly attached microorganisms can be effectively eliminated from chicken skin.

Phase I study of weekly nab-paclitaxel + weekly cetuximab + intensity-modulated radiation therapy (IMRT) in patients with stage III-IVB head and neck squamous cell carcinoma (HNSCC)

BACKGROUND

There is a clinical need to improve the efficacy of standard cetuximab + concurrent intensity-modulated radiation therapy (IMRT) for patients with locally and/or regionally advanced HNSCC. Taxanes have radiosensitizing activity against HNSCC, and nab-paclitaxel may offer therapeutic advantage in comparison with other taxanes.

PATIENTS AND METHODS

This was a single-institution phase I study with a modified 3 + 3 design. Four dose levels (DLs) of weekly nab-paclitaxel were explored (30, 45, 60, and 80 mg/m(2)), given with standard weekly cetuximab (450 mg/m(2) loading dose followed by 250 mg/m(2) weekly) and concurrent IMRT (total dose, 70 Gy).

RESULTS

Twenty-five eligible patients (20 M, 5 F) enrolled, with median age 58 years (range, 46-84 years). Primary tumor sites were oropharynx, 19 (10 human papillomavirus [HPV] pos, 8 HPV neg, 1 not done); neck node with unknown primary, 2; larynx 2; and oral cavity and maxillary sinus, 1 each. Seven patients had received prior induction chemotherapy. Maximum tolerated dose (MTD) was exceeded at DL4 (nab-paclitaxel, 80 mg/m(2)) with three dose-limiting toxicities (DLTs) (grade 3 neuropathy, grade 3 dehydration, with grade 3 mucositis grade 3 anemia) among five assessable patients. There was only one DLT (grade 3 supraventricular tachycardia) among six patients at DL3 (nab-paclitaxel, 60 mg/m(2)), and this was deemed the MTD. Among 23 assessable patients, the most common ≥ g3 AEs were lymphopenia 100%, functional mucositis 65%, and pain in throat/oral cavity 52%. At a median follow-up of 33 months, 2-year failure-free survival (FFS) is 65% [95% confidence interval (CI) 42% to 81%] and 2-year overall survival (OS) is 91% (95% CI 69-97).

CONCLUSION

The recommended phase II dose for nab-paclitaxel is 60 mg/m(2) weekly when given standard weekly cetuximab and concurrent IMRT. This regimen merits further study as a nonplatinum alternative to IMRT + cetuximab alone.

CLINICALTRIALSGOV ID

NCT00736619.

An alternative local anaesthesia technique to reduce pain in paediatric patients during needle insertion

AIM

Pain control, which is necessary during most dental procedures, is administered by injecting a local anaesthetic. Because the injection itself can be painful, the procedure via which pain is reduced warrants continued investigation. Only a few studies regarding the reaction of children to dental needle insertion without the use of topical anaesthetics have been reported. This study was conducted to evaluate the efficacy of the local anaesthetic procedure without topical application as compared to the conventional insertion technique for alleviating pain in children receiving local anaesthesia injections.

MATERIALS AND METHODS

For the alternative injection procedure, the dentist quickly and gently pulled or pushed the clean and dried loose tissue at the injection site over the tip of the needle to a depth of 1 to 1.5 mm. When the end of the bevel of the needle tip entered the tissue, a few drops of solution were released, after which the needle was advanced to its proper and intended depth to continue anaesthetic release.

RESULTS

There was a significant difference regarding the pain response between the alternative insertion technique (less painful) and the conventional one according to Sound, Eye, and Motor (SEM) scale ratings (P < 0.000). No significant difference was observed in the response between the maxilla and mandible, nor between boys and girls, between the conventional and alternative techniques.

CONCLUSION

This alternative technique can reduce discomfort in paediatric dental patients and allow the clinician to administer a superficial local anaesthesia injection before the needle is advanced into deeper tissue. This technique is simple, quick, devoid of additional costs, and potentially more effective than the conventional needle insertion method.

Excretory-secretory products of Giardia lamblia induce interleukin-8 production in human colonic cells via activation of p38, ERK1/2, NF-κB and AP-1

Giardia lamblia, a pathogen causing diarrhoeal outbreaks, is interesting how it triggers immune response in the human epithelial cells. This study defined the crucial roles of signalling components involved in G. lamblia-induced cytokine production in human epithelial cells. Incubation of the gastrointestinal cell line HT-29 with G. lamblia GS trophozoites triggered production of interleukin (IL)-1β, IL-8 and tumour necrosis factor (TNF)-α. IL-8 production was not significantly decreased by physically separating the HT-29 cells and G. lamblia GS trophozoites. Indeed, treatment of HT-29 with G. lamblia excretory-secretory products (ESP) induced IL-8 production. Electrophoretic mobility gel shift and transfection assays using mutagenized IL-8 promoter reporter plasmids indicated that IL-8 production by G. lamblia ESP occurs through activation of two transcriptional factors, nuclear factor kappaB (NF-κB) and activator protein 1 (AP-1) in HT-29 cells. In addition, activation of two mitogen-activated protein kinases (MAPKs), p38 and ERK1/2, was also detected in the HT-29 cells stimulated with G. lamblia ESP. Selective inhibition of these MAPKs resulted in decreased production of ESP-induced IL-8. These results indicate that activation of p38, ERK1/2 MAPK, NF-κB and AP-1 comprises the signalling pathway responsible for IL-8 production by G. lamblia ESP.

Relationship between prolactin levels and subjective endocrine-related adverse effects in patients with schizophrenia receiving long-term treatment with amisulpride

INTRODUCTION

We have investigated the categorical prevalence of hyperprolactinemia and examined the relationship between prolactin levels and subjective endocrine-related adverse effects in schizophrenia patients treated with amisulpride during a 1-year period.

METHODS

A total of 111 patients with schizophrenia who were either started on or switched to amisulpride were assessed for prolactin levels and endocrine-related adverse effects using 6 items derived from the Liverpool University neuroleptic side-effect rating scale (LUNSERS) at baseline, 8 weeks, and 1 year.

RESULTS

10 were antipsychotic-naïve, 23 were antipsychotic free for 1 month, 54 discontinued their medication during 1 month prior to study, and 24 maintained their antipsychotics at baseline. At 1 year, hyperprolactinemia was found in 75.9% of men and 85.7% of women. Significant increases in mean prolactin levels at week 8 in both sexes were found; this was followed by a significant decrease over 1 year only in women. The proportions of both sexes with hyperprolactinemia increased from baseline to week 8 but remained unchanged at 1 year. Scores on the endocrine-related items of the LUNSERS improved significantly from baseline to week 8 in both sexes and then remained consistent during maintenance treatment. Prolactin levels were significantly higher in the group with baseline hyperprolactinemia than in the group without baseline hyperprolactinemia at all assessment points.

CONCLUSIONS

Amisulpride commonly induces hyperprolactinemia. Although the percentage of patients with hyperprolactinemia remained unchanged during maintenance treatment, serum prolactin levels significantly decreased among women. Self-reported endocrine-related side effects were not associated with prolactin elevation during amisulpride treatment.

Characterization of carbapenem-nonsusceptible Klebsiella pneumoniae bloodstream isolates at a Taiwanese hospital: clinical impacts of lowered breakpoints for carbapenems

This study was conducted in order to characterize carbapenem-nonsusceptible Klebsiella pneumoniae isolates and to evaluate the impacts of recently lowered interpretative breakpoints for carbapenems for Enterobacteriaceae. Among 152 K. pneumoniae bloodstream isolates suspected as AmpC or extended-spectrum β-lactamase (ESBL) producers, 58 (38.2%) isolates were currently interpreted as nonsusceptible to ertapenem, imipenem, or meropenem, and 42 (72.4%) of them were categorized as carbapenem-susceptible by the previous criteria. The high revision rate was associated with the predominance (79.3%) of DHA-1 among the carbapenem-nonsusceptible isolates due to both polyclonal and clonal spread. ESBLs were common (~57%) in both ertapenem-susceptible and -nonsusceptible isolates; however, 84.8% of the carbapenem-nonsusceptible isolates were also AmpC producers. The IMP-8 metallo-β-lactamase was detected in three isolates. Polyacrylamide gel electrophoresis suggested decreased OmpK35 expression in all but one ertapenem-nonsusceptible isolate, and genetic disruptions of ompK35 and ompK36 were detected in 30 and six ertapenem-nonsusceptible isolates, respectively. A comparison between patients infected by AmpC- or ESBL-producing ertapenem-susceptible (n=62) isolates and those with isolates revised as ertapenem-nonsusceptible (n=41) revealed more cases of malignancies (36.6% versus 14.5%; p=0.01) and higher Charlson score (p=0.033) among the patients with ertapenem-nonsusceptible isolates; however, the acquisition of an isolate revised as carbapenem-nonsusceptible was not identified as an independent mortality risk factor.

Clinical usefulness of plasma quantitative polymerase chain reaction assay: diagnosis of cytomegalovirus infection in kidney transplant recipients

BACKGROUND

Preemptive therapy is used to prevent cytomegalovirus (CMV) disease in transplant recipients. The CMV antigenemia assay, which has been commonly used as a predictive marker for preemptive therapy, requires intensive labor and immediate processing. We compared the cutoff value of plasma CMV polymerase chain reaction (PCR) with CMV antigenemia in kidney transplant recipients.

METHODS

We compared two diagnostic methods for CMV infection in kidney transplant recipients: quantitative PCR (qPCR) versus antigenemia. We evaluated the optimal cutoff value of plasma CMV qPCR by using receiver-operating characteristic curves for specific antigenemia values. All kidney transplant recipients from January 2004 to January 2005 were enrolled and followed with CMV antigenemia and plasma CMV qPCR.

RESULTS

The analyses were performed on 899 samples collected from 111 patients in the early posttransplant period, matching 84.1% of patients for the results of CMV antigenemia and plasma CMV qPCR. For patients with symptomatic CMV infection and disease, who showed ≥25 positive cells in the antigenemia assay, the cutoff value for qPCR was 17.8 copies/μL with a sensitivity of 97.1%, a specificity of 89.1%, and a positive predictive value of 26.6%.

CONCLUSIONS

Diagnostic assays for CMV such as CMV antigenemia and quantitative plasma PCR, showed similar diagnostic values. They are the methods of choice for the diagnosis and monitoring of active CMV infection after kidney transplantation. However, because of the relatively low positive predictive value of qPCR, this test may lead to unnecessary preemptive treatment in kidney transplant recipients.

A new compound, 1H,8H-pyrano[3,4-c]pyran-1,8-dione, suppresses airway epithelial cell inflammatory responses in a murine model of asthma

Clinical and experimental studies have established eosinophilia as a sign of allergic disorders. Activation of eosinophils in the airways is believed to cause epithelial tissue injury, contraction of airway smooth muscle and increased bronchial responsiveness. As part of the search for new antiasthmatic agents produced by medicinal plants, the effects of 270 standardized medicinal plant extracts on cytokine-activated A549 human lung epithelial cells were evaluated. After several rounds of activity-guided screening, the new natural compound, 1H,8H-Pyrano[3,4-c]pyran-1,8-dione (PPY), was isolated from Vitex rotundifolia L. To elucidate the mechanism by which the anti-asthmatic responses of PPY occurred in vitro, lung epithelial cells (A549 cell) were stimulated with TNF-alpha, IL-4 and IL-1beta to induce the expression of chemokines and adhesion molecules involved in eosinophil chemotaxis. PPY treatments reduced the expression of eotaxin, IL-8, IL-16 and VCAM-1 mRNA significantly. Additionally, PPY reduced eotaxin secretion in a dose-dependent manner and significantly inhibited eosinophil migration toward A549 medium. In addition, PPY treatment suppressed the phosphorylation of p65 and ERK1/2, suggesting that it can inhibit the MAPK/NF-KB pathway. To clarify the anti-inflammatory and antiasthmatic effects of PPY in vivo, we examined the influence of PPY on the development of pulmonary eosinophilic inflammation in a murine model of asthma. To accomplish this, mice were sensitized and challenged with ovalbumin (OVA) and then examined for the following typical asthmatic reactions: an increase in the number of eosinophils in BALF; the presence of Th2 cytokines such as IL-4 and IL-5 in the BALF; the presence of allergen-specific IgE in the serum; and a marked influx of inflammatory cells into the lung. Taken together, our results revealed that PPY exerts profound inhibitory effects on the accumulation of eosinophils into the airways while reducing the levels of IL-4, IL-5, and IL-13 in the BALF. Therefore, these results suggest that PPY may be useful as a new therapeutic drug for the treatment of allergic asthma.

Direct application of the PCR restriction analysis method for identifying NTM species in AFB smear-positive respiratory specimens

The early differentiation of Mycobacterium tuberculosis from non-tuberculous mycobacteria (NTM) and the identification of NTM species are crucial for the proper management of patients with smear-positive sputum. We evaluated the usefulness of a polymerase chain reaction restriction analysis (PRA) method based on the rpoB gene for identifying NTM species in a study of 121 smear-positive respiratory specimens with presumed NTM. The PRA method amplified mycobacterial DNA in 72 specimens (60%) and differentiated NTM species correctly in 68 (94%). The PRA method could be a useful and rapid method for identifying NTM species in smear-positive respiratory specimens when urgent clinical decisions are required.

Expression of N-methyl-d-aspartate receptor 1 in rats with chronic ocular hypertension

High levels of glutamate can be toxic to retinal ganglion cells (RGCs). This study investigated the relationship between the N-methyl-d-aspartate receptor 1 (NR) and RGC death in a rat model of chronic ocular hypertension (COHT). COHT was induced in one eye of each rat by episcleral vein cauterization. Retinal protein expression was evaluated at 1, 3, 5 and 9 weeks after cauterization. Quantitative real-time polymerase chain reaction and Western blot analysis showed that NR1 expression was significantly increased in cauterized retinae. NR1 immunoreactivity was observed in the inner nuclear layer (INL) and ganglion cell layer (GCL) in the retina of rats with COHT. RGC density was evaluated after retrograde labeling with fluoro-gold (FG) and 4-di-10-ASP (DiA). A significant decrease in RGC density was observed in ocular hypertensive eyes, and NR1 expression in the GCL suggested an important role of NR1 in the death of RGCs. Memantine (10 mg/kg), an N-methyl-d-aspartate receptor antagonist, was administered orally once daily for up to 5 weeks, while rats in the control group received vehicle phosphate-buffered saline only. Treatment with memantine resulted in a significant reduction in RGC loss and NR1 expression in the eyes of rats COHT. These findings suggest that excessive expression of NR1 is involved in RGC death in glaucoma.

Molecular characterization of enteroviruses isolated from patients with aseptic meningitis in Korea, 2005

Enteroviruses are the most common causative agents of aseptic meningitis. In 2005, an outbreak of aseptic meningitis occurred in Seoul, Korea, which appeared to be caused by certain enterovirus strains. This study analyzed the clinical isolates from 24 different aseptic meningitis patients at our center from January to September 2005. Serotyping using type-specific antisera, RT-PCR, and direct sequencing of the 5' noncoding and VP1 regions were carried out. The serotyping study identified 15 coxsackievirus B5 (CBV5), 4 coxsackievirus B1 (CBV1), 1 coxsackievirus B3 (CBV3) and 4 echovirus 9 (ECV9). Phylogenic analysis of the VP1 region revealed CBV5 to be the most predominant strain (15 strains). Twelve of these strains were grouped together with recent strains isolated in China and France. The 12 CBV5 strains contained a novel amino acid change in the BC-loop (the 90th and 91st, AY --> GN) compared to the reference strain (1954/UK/85). The amino acid changes in the BC-loop in some recent CBV5 strains tend to be located in the C-terminal part, and these changes suggest some antigenic significance.

Pulmonary TB and NTM lung disease: comparison of characteristics in patients with AFB smear-positive sputum

OBJECTIVE

To compare the clinical and radiographic features of pulmonary tuberculosis (PTB) and non-tuberculous mycobacteria (NTM) lung disease in patients with acid-fast bacilli (AFB) positive sputum specimens.

DESIGN

The initial clinical and radiographic features of 229 PTB patients were compared with those of 70 patients with NTM lung disease. The most commonly involved organisms in the NTM lung disease cases were Mycobacterium avium complex (n = 38, 54%) and M. abscessus (n = 26, 37%).

RESULTS

Clinical and radiographic findings that were more common in patients with NTM lung disease than in PTB patients were: older age (P < 0.001), non-smoker (P < 0.001), history of previous TB treatment (P < 0.001), absence of pleural effusion (P = 0.017), involvement of middle and/or lower lung zones (P = 0.007), and bilateral disease (P = 0.005). Multivariate analysis showed that older age (> or = 40 years), non-smoker, previous TB treatment, absence of pleural effusion and involvement of middle and/or lower lung zones were significant independent predictors for NTM lung disease.

CONCLUSIONS

There is considerable overlap in the clinical and radiographic appearances of PTB and NTM lung disease. The isolation and identification of causative organisms are mandatory for a correct diagnosis in patients with AFB-positive sputum specimens.

Rapid helper T-cell recovery above 200 × 106/l at 3 months correlates to successful transplant outcomes after allogeneic stem cell transplantation

The current study evaluates the role of quantitative measurement of peripheral lymphocyte subsets, especially CD4+ helper T-cell recovery, in predicting transplant outcomes including overall survival (OS) and non-relapse mortality (NRM) after allogeneic stem cell transplantation. A total of 69 allogeneic recipients were included with following diagnoses: acute myeloid leukemia 42, acute lymphoblastic leukemia 5, chronic myeloid leukemia 15, non-Hodgkin's lymphoma 5 and high-risk myelodysplastic syndrome 2. The peripheral lymphocyte subset counts (CD3+ T cells, CD3+4+ helper T cells, CD3+8+ cytotoxic T cells, CD19+ B cells, and CD56+ natural killer cells) were measured at 3, 6 and 12 months. The CD4+ helper T-cell reconstitution at 3 months was strongly correlated with OS (P<0.0001), NRM (P=0.0007), and opportunistic infections (P=0.0108) at the cutoff value of 200 x 10(6)/l CD4(+) helper T cells. Rapid CD4+ helper T-cell recovery was also associated with a higher CD4+ helper T-cell transplant dose (P=0.006) and donor type (P<0.001). An early CD4+ helper T-cell recovery at 3 months correlated with a subsequent faster helper T-cell recovery until 12 months, yet not with B-cell recovery. In a multivariate analysis, rapid recovery of CD4+ helper T cells at 3 months was a favorable prognostic factor together with higher CD34+ cell transplant dose in terms of OS (P=0.001) and NRM (P=0.005).

Protective role of interleukin-10 promoter gene polymorphism in the pathogenesis of invasive pulmonary aspergillosis after allogeneic stem cell transplantation

The current study attempted to evaluate the association between the IL-10 promoter gene single nucleotide polymorphism (SNP) and invasive pulmonary aspergillosis (IPA) after allogeneic stem cell transplantation (SCT) in 105 patients. Three single-nucleotide polymorphisms were investigated in the proximal region of the IL-10 promoter gene (-1082/-819/-592). Two haplotypes (1082*A/819*T/592*A [ATA] and 1082*A/819*C/592*C [ACC]) were found in the current study. The overall incidence of IPA was estimated as 14.1+/-4.5% with a median onset at 186 days post-transplant (62 approximately 405 days). An increased occurrence of IPA was noted dependent on the IL-10 haplotype (0% vs 11.5+/-6.4% vs 19.7+/-7.7% for ACC/ACC vs ATA/ACC vs ATA/ATA haplotype, P=0.0307 when comparing ACC with non-ACC haplotype). In a multivariate survival analysis using Cox's proportional hazard model, the IL-10 promoter gene SNPs were identified as an independent predictive factor for the development of IPA (P=0.012, hazard ratio (HR) 9.3), along with an histocompatibility leukocyte antigen (HLA)-identical donor (P=0.005, HR 16.3), the CD34+ cell dose transplanted (P=0.004, HR 26.5), and time-dependent chronic graft-versus-host disease (GVHD; P=0.049, HR 16.0). The IL-10 ACC haplotype was found to have an apparent protective role in the development of IPA after allogeneic transplantation, regardless of HLA-disparity or chronic GVHD.

Prognostic significance of platelet recovery pattern after allogeneic HLA-identical sibling transplantation and its association with severe acute GVHD

Thrombocytopenia (TP) is a frequent complication after allogeneic stem cell transplantation (SCT) and regarded as a poor prognostic factor when assessed beyond day 100. However, little is known about the clinical significance of the platelet recovery pattern before chronic graft-versus-host disease (GVHD) develops. Eighty-five patients undergoing HLA-identical sibling SCT were stratified according to their platelet recovery pattern between day +30 and +90 and the transplant outcomes analyzed, along with the association of each component of the acute GVHD grading system. Fifteen patients (18%) were classified with persistent TP, 33 patients (39%) with unstable TP, and 37 patients (43%) as non-TP. Persistent TP, which was strongly associated with severe acute GVHD (P<0.001), exhibited the worst 2-year OS (P<0.0001) and highest NRM (P<0.0001) and opportunistic infection rates (P<0.0001). In multivariate analyses, the platelet recovery pattern was identified as an independent prognostic factor (P=0.02) together with the disease risk (P=0.02) in terms of OS, and the only independent prognostic factor in terms of NRM (P=0.005) and the incidence of infectious events (P<0.001). Persistent TP was strongly associated with the development of extensive chronic GVHD (P=0.03). The platelet recovery pattern between day +30 and +90 can be used to predict the prognosis of SCT recipients.

Recovery rate of NTM from AFB smear-positive sputum specimens at a medical centre in South Korea

OBJECTIVE

To investigate the recovery rate of non-tuberculous mycobacteria (NTM) from acid-fast bacilli (AFB) smear-positive sputum specimens at a tertiary care medical centre in South Korea with a high pulmonary tuberculosis (PTB) burden.

DESIGN

Retrospective analysis of data from AFB smear- and culture-positive sputum specimens collected between January 1998 and December 2001.

RESULTS

Over 4 years, 1328 sputum specimens collected from 616 patients were AFB smear- and culture-positive. NTM were recovered from 9.1% (121/1328) of the smear-positive sputum specimens, and from 8.1% (50/616) of patients with smear-positive sputum. NTM were isolated at least twice in 94% (47/50) of the patients from whom NTM was recovered. The most common organism found was Mycobacterium avium complex, followed by M. abscessus.

CONCLUSION

These results suggest that a substantial proportion of patients at a tertiary care medical centre in South Korea with AFB smear-positive sputum specimens may have NTM lung disease rather than PTB.

Risk factors for late cytomegalovirus infection after allogeneic stem cell transplantation using HLA-matched sibling donor: donor lymphocyte infusion and previous history of early CMV infection

An increased incidence of late cytomegalovirus (CMV) infection has been reported during the last decade since the introduction of ganciclovir (GCV) prophylaxis or GCV pre-emptive therapy. Given that a donor lymphocyte infusion (DLI) can induce more severe GVHD, this may predispose a patient to late CMV infection. In all, 64 patients (median age 36, M/F 38/26) underwent allogeneic stem cell transplantation (SCT) using a matched sibling donor with bone marrow (n=9) or peripheral blood stem cells (n=55). The overall incidence of CMV infection, early and late CMV infection was 46.9 (30/64), 42.2 (27/64), and 16.4% (9/55), respectively. Early CMV infection was treated with GCV pre-emptive therapy that produced a 92.6% success rate. Among the 20 patients who received 35 DLIs, late CMV infection developed in eight (42.1%) of 19 evaluable cases with a median onset at 127 days post transplant. Risk factors for late CMV infection in a logistic regression analysis included DLIs (P=0.001) and a previous history of CMV infection (P=0.006). In conclusion, late CMV infection was strongly associated with DLIs and a previous history of early CMV infection. Accordingly, extended surveillance of CMV antigenemia is recommended for patients receiving DLIs or who have a previous history of CMV infection.

Effect of infusing lactoferrin hydrolysate into bovine mammary glands with subclinical mastitis

The therapeutic effect of administering lactoferrin hydrolysate (LFH) into the mammary glands of cows with subclinical mastitis was evaluated. Seven millilitres of a preparation of LFH (7% protein) was infused into 35 quarters of 25 cows with subclinical mastitis. The numbers of bacteria in the milk from infected quarters decreased, and bacteria disappeared by the 14th day after the administration of LFH. The mean somatic cell counts (SCC) peaked one day after administration of LFH and the counts were significantly p < 0.01) decreased on days 7, 14 and 21 compared to those before the administration of LFH. The mean lactoferrin concentration in the milk peaked on days 2 or 3 and then gradually decreased to day 14, returning to the level before the administration of LFH. It appears that administration of LFH may have a therapeutic effect when infused into the quarters of cows with subclinical mastitis.

A pilot study of cytoreductive chemotherapy combined with infusion of additional peripheral blood stem cells reserved at time of harvest for transplantation in case of relapsed hematologic malignancies after allogeneic peripheral blood stem cell transplant

Reharvesting leukocytes from donors for a donor leukocyte infusion (DLI) is inconvenient and occasionally impossible in case of unrelated donors. It is well known that the effect of a growth factor-primed DLI is comparable to that of a nonprimed DLI. In total, 42 patients with hematologic malignancies and a high risk of relapse were allocated, on an intent-to-treat basis, a peripheral blood stem cell transplantation (PBSCT) from HLA-matched sibling donors, and then at the time of harvest, additional peripheral blood stem cells (PBSCs) were also reserved for a therapeutic primed DLI in case of relapse. In all, 12 patients who relapsed after allogeneic PBSCT were treated with mainly cytarabine-based chemotherapy followed by a cryopreserved PBSC infusion. The median dose of CD3+ and CD34+ cells for the primed DLIs was 1.43 x 10(8)/kg and 4.75 x 10(6)/kg, respectively. Six of the 12 relapsed patients exhibited a complete response after the primed DLI, plus their 1-year survival rate was 33%. The new development or progression of graft-versus-host disease after a primed DLI was observed in 50% of the patients. Overall, the survival at 1 year was 16.7%. Accordingly, the induction of a graft-versus-leukemia effect through a primed DLI, using additional PBSCs reserved at the original time of harvest, would appear to be feasible for patients with relapsed hematologic malignancies. Furthermore, this approach is also more convenient for donors.

Impact of transplanted CD34+ cell dose in allogeneic unmanipulated peripheral blood stem cell transplantation

The impact of the CD34+ cell dose on chronic graft-versus-host disease (cGVHD) and the clinical outcome was analyzed in 41 consecutive adult patients submitted to allogeneic peripheral blood stem cell transplantation from HLA-identical siblings. The patients were classified into 'low' or 'high' CD34+ cell dose groups based on whether they received less or more than a median CD34+ cell dose of 10.5 x 10(6)/kg, respectively. There was a significant difference in the incidence of extensive cGVHD (low vs high group, 25.0 vs 66.7%, P=0.021) and relapse (47.6 vs 20.0%, P=0.049) between the two groups. With a median follow-up of 335 days, the 3-year survival estimate for the whole population was 47.9%, while that for the low and high groups was 29.9 and 67.8%, respectively (P=0.0434). An inverse relation was noted between the relapse rate and the incidence of extensive cGVHD (P=0.043). It would appear reasonable that the optimal dose of CD34+ cells should be determined based on the disease status or aggressiveness of the malignant cells in each patient. Yet, in the case of patients with a high risk of relapse, transplantation with a CD34+ cell dose of >10.5 x 10(6)/kg would seem to be acceptable to minimize the risk of relapse.

Pseudomonas aeruginosa as a potential cause of antibiotic-associated diarrhea

Although Pseudomonas aeruginosa is not generally considered as a cause of antibiotic-associated diarrhea, several cases of diarrhea caused by P. aeruginosa have been reported. We experienced seven cases of nosocomial diarrhea presumably caused by P. aeruginosa, which was the predominant organism isolated from stool cultures. Clostridium difficile toxin was also positive in one patient. No other potential or recognized enteropathogens were identified from stools. All patients had underlying diseases and had been receiving antibiotics before the diarrheal onset. All of the seven P. aeruginosa isolates were resistant to previously given antibiotics. Diarrhea stopped three days after withdrawal of probable offending antibiotics without specific treatment in two patients. The other five patients having continuous diarrhea despite withdrawal of probable offending antibiotics, were successfully treated with antipseudomonal agents. The median duration of diarrhea after the initiation of treatment was 6.3 days. These data suggest that P. aeruginosa can be a potential cause of antibiotic-associated diarrhea. Further investigations are warranted to evaluate the possible etiologic role of P. aeruginosa in antibiotic-associated diarrhea.

Image reconstruction using the wavelet transform for positron emission tomography

We conducted positron emission tomography (PET) image reconstruction experiments using the wavelet transform. The Wavelet-Vaguelette decomposition was used as a framework from which expressions for the necessary wavelet coefficients might be derived, and then the wavelet shrinkage was applied to the wavelet coefficients for the reconstruction (WVS). The performances of WVS were evaluated and compared with those of the filtered back-projection (FBP) using software phantoms, physical phantoms, and human PET studies. The results demonstrated that WVS gave stable reconstruction over the range of shrinkage parameters and provided better noise and spatial resolution characteristics than FBP.

Carriage of antibiotic-resistant pneumococci among Asian children: a multinational surveillance by the Asian Network for Surveillance of Resistant Pathogens (ANSORP)

To investigate the nasal carriage of antibiotic-resistant pneumococci by children, anterior nasal swabs were done for 4963 children <5 years old in 11 countries in Asia and the Middle East. In total, 1105 pneumococci isolates (carriage rate, 22.3%) were collected, 35.8% of which were found to be nonsusceptible to penicillin. Prevalence of penicillin nonsusceptibility was highest in Taiwan (91.3%), followed by Korea (85.8%), Sri Lanka (76.5%), and Vietnam (70.4%). Penicillin resistance was related to residence in urban areas, enrollment in day care, and a history of otitis media. The most common serogroups were 6 (21.5%), 23 (16.5%), and 19 (15.7%). The most common clone, as assessed by pulsed-field gel electrophoresis, was identical to the Spanish 23F clone and to strains of invasive isolates from adult patients. Data in this study documented the high rate of penicillin or multidrug resistance among isolates of pneumococci carried nasally in children in Asia and the Middle East and showed that this is due to the spread of a few predominant clones in the region.

Production of recombinant bovine lactoferrin N-lobe in insect cells and its antimicrobial activity

Lactoferrin is a multifunctional, iron-binding glycoprotein found in physiological fluids of mammals. In the present study, a gene encoding the N-terminal half (N-lobe) of bovine lactoferrin was cloned and expressed in cultured insect cells using a baculovirus expression system. One mutation was found in the lactoferrin N-lobe gene, but it resulted in no amino acid substitution. The recombinant lactoferrin N-lobe was secreted into the culture medium and partially purified by means of an immobilized heparin column. The recombinant lactoferrin N-lobe secreted was not glycosylated, but it possessed antimicrobial activity toward Escherichia coli O111. The recombinant product synthesized and accumulated in the host cells exhibited greater electrophoretic mobility on SDS-PAGE than the secreted product and showed no potency to inhibit the growth of bacteria. It is thought that the product accumulated intracellularly lacks antimicrobial ability due to its degradation in the host cells or due to disruption of the active conformation.

Epidemiological usefulness of anti-opacity factor antibody screening in schoolchildren

The presence of the anti-opacity factor (anti-OF) antibody (Ab) in the serum used for identifying the OF antigen (Ag) type represents previous or current infection with group A streptococci (GAS) of the OF Ag type. Throat cultures were taken from 172 elementary schoolchildren in Chinju, Korea, and venous blood samples were collected at the same time to screen for the frequency of the anti-OF Ab. After isolation of GAS, the OF Ag of each GAS was identified by inhibition of the opacity reaction with recognized anti-OF sera. The anti-OF Abs in the sera were screened with the six most common OF Ag types. OF22 and OF28 were high in prevalence (28.2 and 20.5%, respectively) among OF Ag types, while anti-OF types 4, 28, and 22 were frequently identified (39.5, 29.7, and 15.7%, respectively) in the sera. Thirty-two of 39 (82.1%) OF Ag-producing GAS carriers, 25 of 34 (73.5%) GAS carriers not producing OF Ag, and 72 of 99 (72.7%) throat culture-negative children harbored the anti-OF Ab. Forty-five (26.2%) of 172 children had two different anti-OF Abs, and 11 (6.4%) had more than three anti-OF Abs. Seventy-five percent of 172 elementary schoolchildren were shown to be previously or currently infected with GAS. The percentages of children positive for the anti-OF Ab were very high regardless of the result of throat culture or OF Ag production of GAS. We could also demonstrate (i) that the prevalent strains of GAS changed according to the time span by determining the difference between the frequencies of OF Ag and anti-OF Ab and (ii) that repeated infections were not uncommon in schoolchildren, as one-third had more than two different anti-OF Abs.

Wavelet methods for inverting the Radon transform with noisy data

Because the Radon transform is a smoothing transform, any noise in the Radon data becomes magnified when the inverse Radon transform is applied. Among the methods used to deal with this problem is the wavelet-vaguelette decomposition (WVD) coupled with wavelet shrinkage, as introduced by Donoho (1995). We extend several results of Donoho and others here. First, we introduce a new sufficient condition on wavelets to generate a WVD. For a general homogeneous operator, whose class includes the Radon transform, we show that a variant of Donoho's method for solving inverse problems can be derived as the exact minimizer of a variational problem that uses a Besov norm as the smoothing functional. We give a new proof of the rate of convergence of wavelet shrinkage that allows us to estimate rather sharply the best shrinkage parameter needed to recover an image from noise-corrupted data. We conduct tomographic reconstruction computations that support the hypothesis that near-optimal shrinkage parameters can be derived if one can estimate only two Besov-space parameters about an image f. Both theoretical and experimental results indicate that our choice of shrinkage parameters yields uniformly better results than Kolaczyk's (1996) variant of Donoho's method and the classical filtered backprojection method.

Korean Nationwide Surveillance of Antimicrobial Resistance of Bacteria in 1998

Antimicrobial resistance surveillance can provide information needed for empirical therapy of antimicrobial agents and for control of resistance. To determine the trend of antimicrobial resistance in Korea, in vitro susceptibility data in 1998 were collected from 25 hospitals participating to a program of Korean Nationwide Surveillance of Antimicrobial Resistance (KONSAR). The data were analyzed based upon hospital location and bed capacity. The results showed that cefoxitin-resistant E. coli and K. pneumoniae and 3rd-generation cephalosporin-resistant K. pneumoniae were prevalent, that 3rd-generation cephalosporin-resistant E. cloacae, S. marcesens and A. baumannii had increased, and ampicillin-resistant S. enterica were not rare. Oxacillin-resistant S. aureus, penicillin-non-susceptible pneumococci and beta-lactamase-producing H. influenzae were prevalent even smaller hospitals surveyed, and an increase of imipenem-resistant P. aeruginosa and vancomycin-resistant E. faecium is a new obvious threat. In general, resistance rates to some old antimicrobial agents, i.e., E. coli to ampicillin and S. aureus to oxacillin were high and did not vary greatly between the different levels of hospitals, while the rates to some of the newer ones, i.e., P. aeruginosa to imipenem, was quite variable and depended on the hospitals, probably reflecting difference in selective pressure.

Molecular characterization of multidrug-resistant Streptococcus pneumoniae isolates in Korea. The Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study Group

Pulsed-field gel electrophoresis, ribotyping, and fingerprinting analysis of 22 invasive isolates of multidrug-resistant (MDR) pneumococci from Korea showed that 59 to 82% were genetically related. DNA sequencing of the PBP 2B gene showed relatively uniform alterations in nucleotides (5.4 to 7.8%) and amino acids (3.0 to 4. 3%), while Asn-276-->Lys, Arg-285-->Cys and Ser-305-->Phe substitutions were unique to Korean MDR strains, suggesting the spread of a few epidemic clones of resistant pneumococci within Korea.

Biological deodorization of hydrogen sulfide using porous lava as a carrier of Thiobacillus thiooxidans

Biological deodorization of hydrogen sulfide (H2S) was studied using porous lava as a carrier of Thiobacillus thiooxidans in a laboratory-scale biofilter. Three different samples of porous lava, A, B, and C, which were obtained from Cheju Island in Korea, were used. The water-holding capacities of samples A, B and C were 0.38, 0.25, and 0.47 g-H2O/g-lava, respectively. The pHs and densities of the lava samples ranged from 8.25-9.24 and 920-1190 kg/m3, respectively. The buffering capacities, expressed as the amount of sulfate added to lower the pH to 4, were 60 g-SO4(2-)/kg-lava for sample A, 50 g-SO4(2-)/kg-lava for B, and 90 g-SO4(2-)/kg-lava for C. To investigate the removal characteristics of H2S by the lava biofilters, T. thiooxidans was immobilized on the lava samples. Biofilters A and C showed a removal capacity of 428 g-S.m(-3).h(-1) when H2S was supplied with 428 g-S.m(-3).h(-1) of inlet load at a space velocity (SV) of 300 h(-1). At the same inlet load and SV, the removal capacity of biofilter B was 396 g-S.m(-3).h(-1). The H2S critical loads of biofilters A, B and C at a SV of 400 h(-1) were 396, 157 and 342 g-S.m(-3).h(-1), respectively. It is suggested that natural, porous lava is a promising candidate as a carrier of microorganisms in biofiltration.

Skin temperature and skin blood flow affect bioelectric impedance study of female fat-free mass

PURPOSE

This study examined the effects of skin temperature (Ts) and skin blood flow (SKBF) on bioelectrical impedance (BIA) measurements of body composition in healthy young females.

METHODS

The Lukaski (FFM(LUK)) and Guo (FFM(GUO)) BIA equations for measuring female fat-free mass (FFM) were used. All subjects (N = 20, age = 18-22 yr) underwent the following measurements under three ambient temperatures (T(amb)): Ts and SKBF for the calf, thigh, biceps, and chest; oral temperature (T(OR)); and the BIA measures of resistance (R) and reactance (Xc). The three T(amb) were 17, 25, and 35 degrees C which were considered as cold (CT), neutral (NT), and hot (HT) conditions, respectively. Their underwater weighing (UWW), lung residual volume, and skinfold thickness were measured in the NT. Data were analyzed using repeated measures of ANOVA and Tukey post-hoc test.

RESULTS

We observed that in the CT mean SKBF and Ts decreased (P < 0.05) and R and Xc increased (P < 0.05), compared with those in both NT and HT. However, in the HT both SKBF and Ts increased and R deceased, but Xc remained unchanged relative to the NT. In these subjects, a net change in Ts of 17 degrees C resulted in a net change in the BIA measure of R of 46 ohms or 2.5 ohms per degree C. These changes affected the estimate of FFM(LUK) between CT, NT, and HT, but not the estimate of FFM(GUO) Regarding the two BIA equations for estimating FFM, the Guo equation underestimated FFM(UWW) (P < 0.05) in the CT, NT, and HT, and the Lukaski equation underestimated FFM(UWW) (P < 0.05) only in the CT, compared with that in the UWW technique.

CONCLUSIONS

Ambient temperature affects Ts and SKBF which in turn influence the BIA measures of R and Xc, especially in the cold ambient temperature; the Guo BIA equation consistently underestimated FFM of young nonobese Chinese women in all temperatures; and the Lukaski equation closely approximates the FFM in the neutral and hot conditions compared with the FFM(UWW).

Role of genotypic analysis of the thymidine kinase gene of herpes simplex virus for determination of neurovirulence and resistance to acyclovir

Mutations in the thymidine kinase (TK) gene of herpes simplex virus (HSV) have been associated with resistance to acyclovir (ACY) and possible recognition of neurotropic strains. We sequenced a 335-bp segment of the TK gene to determine the frequency of mutations in HSV strains recovered from dermal, genital, and cerebrospinal fluid (CSF) specimens (n = 200; 102 HSV type 1 [HSV-1] 98 HSV-2 strains). Four polymorphic sites were detected in HSV-1 strains; C513T, A528G, C575T, and C672T. Among the polymorphisms, only C575T resulted in a change of amino acid sequence (residue 192, Ala-->Val). For HSV-2 strains, only one polymorphism (G420T) which resulted in an amino acid substitution (residue 139, Leu-->Phe) was detected. Phenotypic determination of resistance to ACY by a plaque reduction assay of 48 HSV isolates was not correlated with the sequence results of 11 strains in that 7 of these with genotypic polymorphisms were susceptible to the drug in vitro. In addition, of 32 ACY-resistant HSV strains, 28 (87.5%) had no polymorphisms detected in the 335-bp amplicon of the TK gene. There was no statistical difference in the frequency of polymorphisms according to the source of the specimens. We conclude that the detection of nucleic acid polymorphisms in a previously implicated 335-bp segment of the TK gene cannot be interpreted as indicative of either ACY resistance or neurotropism of HSV strains from dermal, genital, and CSF sources.

Clinical characteristics of acute viral lower respiratory tract infections in hospitalized children in Seoul, 1996-1998

This study was performed to investigate the etiologic agents, age distribution, clinical manifestations and seasonal occurrence of acute viral lower respiratory tract infections in children. We confirmed viral etiologies using nasopharyngeal aspirates in 237 patients of the ages of 15 years or younger who were hospitalized for acute lower respiratory tract infection (ALRI) from March 1996 to February 1998 at Samsung Seoul Hospital, Seoul, Korea. The overall isolation rate was 22.1%. The viral pathogens identified were adenovirus (12.7%), influenza virus type A (21.1%), -type B (13.9%), parainfluenza virus type 1 (13.5%), -type 2 (1.3%), -type 3 (16.0%) and respiratory syncytial virus (21.5%). The occurrence of ALRIs was highest in the first year of life, although parainfluenza virus type 1 infection occurred predominantly in the second year of life and influenza virus caused illnesses in all age groups. The specific viruses are frequently associated with specific clinical syndromes of ALRI. The respiratory agents and associated syndromes frequently have characteristic seasonal patterns. This study will help us to estimate the etiologic agents of ALRI, and establish a program for the prevention and treatment. An annual nationwide survey is necessary to understand the viral epidemiology associated with respiratory illnesses in Korea.

Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.