Engineered Escherichia coli cell factory for anthranilate over-production.

Anthranilate is a key platform chemical in high demand for synthesizing food ingredients, dyes, perfumes, crop protection compounds, pharmaceuticals, and plastics. Microbial-based anthranilate production strategies have been developed to overcome the unstable and expensive supply of anthranilate via chemical synthesis from non-renewable resources. Despite the reports of anthranilate biosynthesis in several engineered cells, the anthranilate production yield is still unsatisfactory. This study designed an Escherichia coli cell factory and optimized the fed-batch culture process to achieve a high titer of anthranilate production. Using the previously constructed shikimate-overproducing E. coli strain, two genes (aroK and aroL) were complemented, and the trpD responsible for transferring the phosphoribosyl group to anthranilate was disrupted to facilitate anthranilate accumulation. The genes with negative effects on anthranilate biosynthesis, including pheA, tyrA, pabA, ubiC, entC, and trpR, were disrupted. In contrast, several shikimate biosynthetic pathway genes, including aroE and tktA, were overexpressed to maximize glucose uptake and the intermediate flux. The rationally designed anthranilate-overproducing E. coli strain grown in an optimized medium produced approximately 4 g/L of anthranilate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for microbial-based anthranilate production will play a key role in complementing traditional chemical-based anthranilate production processes.

Lack of association between stroke and left atrial out-pouching structures: results of a case-control study.

BACKGROUND AND PURPOSE: Clinical significance of out-pouching structures of the left atrium (LA) as potential embolic sources remains unclear. We sought to evaluate the association between stroke and LA out-pouching structures. METHODS: A case-control study was conducted to assess the prevalence of LA out-pouching structures in subjects with and without stroke. Case subjects were 270 stroke patients who had undergone cardiac CT. Control subjects were 270 age- and sex-matched patients without a history of stroke and who had undergone cardiac CT. Presence of LA out-pouching structures was determined by ECG-gated cardiac CT. The location of out-pouching structures was categorized as near Bachmann bundle, anterior, inferoseptal, inferior, and lateral. The prevalence, number and location of out-pouching structures and clinical characteristics were compared between the two groups. RESULTS: One hundred sixty eight out-pouching structures were identified in 139 stroke patients (51%), while a total of 169 out-pouching structures were found in 155 control patients (57%) (p=0.1949). The prevalence of LA out-pouching structures with different locations was not significantly different between the stroke group and control group. In the stroke group, the prevalence of out-pouching structures was not significantly different by subtypes of ischemic stroke and the prevalence of LA out-pouching structures was not different between patients with atrial fibrillation (AF) and without AF. CONCLUSION: The left atrial out-pouching structures are commonly seen in a population with and without stroke with similar prevalence. Our study suggests that LA out-pouching structures are not significant risk factors of stroke.

C-arm cone-beam CT-guided percutaneous transthoracic needle biopsy of small (≤ 20 mm) lung nodules: diagnostic accuracy and complications in 161 patients.

OBJECTIVE: The purpose of this study is to retrospectively evaluate the diagnostic accuracy and complications of C-arm cone-beam CT (CBCT)-guided percutaneous transthoracic needle biopsy (PTNB) for small (≤ 20 mm) lung nodules and their possible influencing factors. MATERIALS AND METHODS: From March 2009 to July 2010, 161 consecutive patients (77 men and 84 women; mean [± SD] age, 61 ± 11.8 years; range, 29-85 years) with 173 small (≤ 20 mm) lung nodules underwent CBCT-guided PTNB performed by an experienced chest radiologist in a tertiary referral hospital. The diagnostic accuracy, sensitivity, specificity, and complication rates were statistically evaluated, and influencing factors were assessed using univariate and subsequent multivariate analysis. RESULTS: Of 173 nodules (mean size, 15 ± 3.7 mm), 94 (54.3%) were diagnosed as malignant, 69 (39.9%) as benign, and 10 (5.8%) as indeterminate. On PTNB, 160 nodules were correctly diagnosed and three were false-negatives. Diagnostic accuracy, sensitivity, and specificity were 98.2%, 96.8%, and 100%, respectively. No factors significantly decreased diagnostic accuracy. As for complications, pneumothorax, hemoptysis, and chest pain occurred in 55 (31.8%), 25 (14.5%), and two (1.2%) patients, respectively. Multivariate analysis revealed that the presence of emphysema along the needle pathway was a significant risk factor (odds ratio [OR], 10.11), and the occurrence of hemoptysis was a significant protective factor (OR, 0.28) against pneumothorax. Ground-glass nodules were found to be a significant independent risk factor for hemoptysis (OR, 5.10). CONCLUSION: C-arm CBCT-guided PTNB is highly accurate for small lung nodules, and the diagnostic accuracy does not significantly decrease even in technically challenging conditions.

Outcome predictors affecting the efficacy of clonazepam therapy for the management of burning mouth syndrome (BMS).

BMS is a common condition characterized by chronic oral mucosal pain condition and primarily affects elderly women. Although clonazepam therapy has been widely used due to its efficacy, it is not always effective because of the complexity of BMS pathogenesis. In this study, we have investigated outcome predictors of clonazepam therapy in patients with BMS. One hundred patients with BMS (7 men and 93 women, mean age 58.5 ± 10.8 years) were instructed to take 0.5mg of clonazepam once or twice daily for 4 weeks. The patients were sub-grouped according to psychological status, salivary flow rate, presence of psychiatric medications, symptom area and duration, symptom severity, presence of oral parafunctions, and accompanying oral complaints. The changes in symptoms were analyzed and compared between the sub-groups. Subjects with T-scores ≤50 for each psychological symptom dimension, a greater degree of initial symptoms (visual analog scale (VAS)≥5), and accompanying oral complaints, such as xerostomia and taste disturbance, displayed greater decreases in symptoms compared with their counterparts. In conclusion, psychological status, initial symptom severity, and the presence of xerostomia and/or taste disturbance can serve as outcome predictors of clonazepam therapy for patients with BMS.

Outcome predictors of initial treatment with topical lubricant and parafunctional habit control in burning mouth syndrome (BMS).

Burning mouth syndrome (BMS) is a common chronic pain condition which mainly affects elderly women. The concomitant prescription of topical lubricants with oral parafunctional habit control has been reported as an effective initial approach for patients with BMS. In this study, we have investigated outcome predictors of this initial treatment in patients with BMS. One hundred forty patients with BMS (12 men and 128 women, mean age 59.9±10.7 years) were instructed to avoid oral parafunctions and to use topical lubricant for 2 weeks. The patients were sub-grouped according to psychological status, salivary flow rate, presence of psychiatric medications, symptom area and duration, symptom severity, presence of oral parafunctions, and accompanying oral complaints. The changes in symptoms were analyzed and compared between sub-groups. Subjects with T-scores≤50 for each psychological symptom dimension, a flow rate of stimulated whole saliva (SWS)>0.5 ml/min, no psychiatric medications, and a greater degree of initial symptoms (VAS≥5) displayed greater decreases in symptoms compared with their counterparts. In conclusion, psychological status, psychiatric medications, flow rate SWS, and initial symptom severity can be outcome predictors of the initial treatment approach for patients with BMS.

Phase II study to topotecan and cisplatin in advanced hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma remains a highly chemoresistant neoplasm and is a common malignancy with poor prognosis in Korea. We performed a phase II study to evaluate the efficacy and toxicities of topotecan and cisplatin combination chemotherapy for advanced hepatocellular carcinoma. METHODS: Between November 1999 and May 2001, ten patients with histologically proven hepatocellular carcinoma were enrolled in this study. The median age was 54 (range: 53-74) years and all were male. Six patients demonstrated stage IV, 1 stage IIIC, 2 stage IIIB and 1 stage IIIA. Six patients showed a ECOG performance status of 1. The treatment regimen consisted of topotecan 1.25 mg/m2 and cisplatin 20 mg/m2 for 5 days. The treatment was repeated every 4 weeks. Toxicities were evaluated according to WHO toxicity criteria. RESULTS: All ten patients were evaluable for response and toxicity. There was only one patient who achieved partial response. The overall response rate was 10% (95% C.I.) and the response duration was 46 weeks. The median survival of all patients was 21 (range: 17-54+) weeks. During a total of 24 cycles, neutropenia of WHO grade 3 and 4 occurred in 33%, thrombocytopenia in 33% and anemia in 21%. In non-hematologic toxicity, diarrhea and hepatoxicity of grade 3 occurred in 1 and 2 patients, respectively. But there was no treatment-related death. CONCLUSION: When used in this dose and schedule, topotecan and cisplatin combination chemotherapy does not seem to be effective for patients with advanced hepatocellular carcinoma.