Alpha modulation in parietal and retrosplenial cortex correlates with navigation performance

The present study investigated the brain dynamics accompanying spatial navigation based on distinct reference frames. Participants preferentially using an allocentric or an egocentric reference frame navigated through virtual tunnels and reported their homing direction at the end of each trial based on their spatial representation of the passage. Task-related electroencephalographic (EEG) dynamics were analyzed based on independent component analysis (ICA) and subsequent clustering of independent components. Parietal alpha desynchronization during encoding of spatial information predicted homing performance for participants using an egocentric reference frame. In contrast, retrosplenial and occipital alpha desynchronization during retrieval covaried with homing performance of participants using an allocentric reference frame. These results support the assumption of distinct neural networks underlying the computation of distinct reference frames and reveal a direct relationship of alpha modulation in parietal and retrosplenial areas with encoding and retrieval of spatial information for homing behavior.     

Effects of transcription factor activator protein-1 on interleukin-8 expression and enteritis in response to <Emphasis Type="Italic">Clostridium difficile</Emphasis> toxin A

Clostridium difficile toxin A causes acute colitis associated with intense infiltration of neutrophils. Although C. difficile toxin A is known to induce nuclear factor-kappaB-mediated chemokine expression in intestinal epithelial cells, little is known about its effect on the regulation of activator protein-1 (AP-1) by mitogen-activated protein kinase (MAPK). In the present study, we investigated whether the MAPK and AP-1 signaling pathway is involved in interleukin (IL)-8 expression and enteric inflammation in response to stimulation with toxin A. Toxin A activated MAPK and AP-1 composed of c-Jun/c-Fos heterodimers in primary intestinal epithelial cells and HT-29 cell lines. Transfection with mutant genes for Ras, c-Jun, p38, or c-Jun N-terminal kinase (JNK) significantly inhibited C. difficile toxin A-induced activation of AP-1 and expression of IL-8 in HT-29 cell lines. Furthermore, the p38 inhibitor SB203580 attenuated toxin A-induced inflammation in vivo in the mouse ileum, evidenced by a significant decrease in neutrophil infiltration, villous destruction, and mucosal congestion. Our results suggest that the Ras/MAPK cascade acts as the upstream signaling for AP-1 activation and IL-8 expression in toxin A-stimulated intestinal epithelial cells and may be involved in the development of enteritis after infection with toxin A-producing C. difficile.     

Outpatient-basis chemotherapy of oxaliplatin, 5-fluorouracil, and leucovorin as first-line treatment for patients with metastatic or recurrent colorectal cancer

The objectives of the present study were to evaluate the efficacy and safety of an outpatient-basis chemotherapy of oxaliplatin, 5-fluorouracil, and leucovorin as the first-line treatment for patients with advanced colorectal cancer. Forty-three histologically confirmed patients with metastatic or recurrent colorectal cancer were enrolled. The chemotherapy consisted of oxaliplatin 85 mg/m(2) as a 2-hr infusion on day 1, plus leucovorin 30 mg/m(2) over 10 min, followed by bolus 5-fluorouracil 400 mg/m(2) and an 8-hr infusion of 5-fluorouracil 600 mg/m(2) on days 1 and 2 (modified FOLFOX4), all of which were administered on an outpatient basis every 2 weeks. The median age was 58 yr (range 33-72 yr), and 25 (58.1%) patients had metastatic diseases. Eventually, 39 patients were assessable for efficacy and all assessable for toxicity. Four (9.3%) complete responses and 11 (25.6%) partial responses were confirmed, giving an overall response rate of 34.9% (95% CI; 20.0-49.7%). The median time to progression and median overall survival for all patients was 6.1 months and 17.4 months, respectively. Grade 3/4 neutropenia occurred in 2 patients (4.7%) and febrile neutropenia was observed in 1 patient (2.3%). Modified FOLFOX4, an outpatient-basis regimen, was found to be well-tolerated and effective as the first-line chemotherapy in patients with advanced colorectal cancer.     

Analysis of prognostic factors and treatment modality changes in breast cancer: a single institution study in Korea

PURPOSE: To determine the effects of new breast cancer treatments and to provide a baseline for monitoring the development of breast cancer in Korean women, we conducted an analysis at our institution to determine long-term clinicopathological features, survival rates, and prognostic factors. MATERIALS AND METHODS: This study retrospectively analyzed 2,403 patients between Sep 1994 and Dec 2002, who underwent breast cancer surgery at Samsung Medical Center in Korea. Demographic data, pathologic records and surgical records were collected. RESULTS: After a median follow-up duration of 121.9 (range: 2-158.1) months, the 5-year disease free survival (DFS) was 82.8% and the 10-year DFS was 74.7%. The 5-year and 10-year overall survival (OS) rates were 89.4% and 82.9%, respectively. Using multivariate analyses, we determined that the nodal status (p < 0.001), angioinvasion (p < 0.001), positive PR (p < 0.001), and C-erb-B2 (p < 0.001) were independent prognostic factors for OS. The frequency of breast conserving surgery was 33.9% before Dec 1999, and increased up to 44.1% by year Dec 2002. CONCLUSION: Most of the prognostic variables and clinical characteristics of the Korean breast cancer patients were similar to those reported for Western populations. However, the age distribution in Korean patients seemed to be different from that in patients from Western countries.     

Clinical features reflect exon sites of EGFR mutations in patients with resected non-small-cell lung cancer

The aim of the current study was to determine the clinical significance according to the subtypes of epidermal growth factor receptor (EGFR) mutations and presence of KRAS mutations in operable non-small-cell lung cancer (NSCLC). We sequenced exons 18-21 of the EGFR tyrosine kinase domain and examined mutations in codons 12 and 13 of KRAS in tissues of patients with NSCLC who had undergone surgical resection. EGFR mutations were more frequent in never-smokers than smokers (33% vs. 14%, respectively; p=0.009) and in females than in males (31% vs. 16%, respectively; p=0.036). Mutations in exon 18-19 and 20-21 were found in 10 and 22 patients, respectively. Never-smokers and broncho-alveolar cell carcinoma features were positively associated with a mutation in exon 18-19 (p=0.027 and 0.016, respectively). The five-year survival rate in patients with a mutation in exons 18-19 (100%) was higher than that in patients without such mutation (47%; p=0.021). KRAS mutations were found in 16 patients (12%) and were not related to the overall survival (p=0.742). Patients with an EGFR mutation in exons 18-19 had better survival than patients without such mutation. Subtypes of EGFR mutations may be prognostic factors in patients undergoing curative resection.     

Human placenta-derived feeders support prolonged undifferentiated propagation of a human embryonic stem cell line, SNUhES3: comparison with human bone marrow-derived feeders

Co-culture of human embryonic stem (ES) cells on mouse fibroblast feeders is the commonly used method for in vitro expansion of human ES cells in an undifferentiated state. However, it has potential risks of pathogen transmission from animals; thus, human cell-derived feeders have been employed to minimize this problem. In this study, we compared human placenta-derived feeders with bone marrow to demonstrate its effectiveness as feeders for in vitro long-term culture of human ES cells. We cultured a human ES cell line, SNUhES3, on human placenta-derived mesenchymal stem cell feeders and compared their culture efficiency with human bone marrow-derived feeders and control group (mouse fibroblast feeders, STO). The mean number of human ES cell colonies was 166 +/- 35 in the placenta feeders; this was significantly higher than bone marrow-derived feeders (87 +/- 16, p < 0.05). We could propagate the culture of SNUhES3 on the placenta feeders past the 50th week similar to control group. During the culture, the maintenance of undifferentiated state of SNUhES3 was demonstrated by the expression of SSEA-4, TRA-1-81, TRA-1-60, and Oct-4. However, we failed to propagate the culture of human ES cells on the human bone marrow-derived feeders past the 5th week. The efficiency of embryoid body formation was similar between placenta and control group, indicating the preservation of differentiation ability. Thus, placenta-derived feeders are more efficient for the long-term in vitro culture of human ES cells than bone marrow-derived feeders suggesting the possible role of placenta as a source for human cell-derived feeders.     

Sulindac prevents esophageal adenocarcinomas induced by gastroduodenal reflux in rats

PURPOSE: It is known that cyclooxygenase (COX)-2 expression is increased in Barrett's esophagus and esophageal adenocarcinomas. We studied COX-2 expression and the effect sulindac has on the genesis of Barrett's esophagus and adenocarcinoma in rats undergoing esophagogastroduodenal anastomosis (EGDA). MATERIALS AND METHODS: Fifty-one rats were divided into a control group (n=27), a 500 ppm sulindac-treated group (n=15) and 1000 ppm sulindac-treated group (n=9). Randomly selected rats were killed by diethyl ether inhalation at 20 and 40 weeks after surgery. RESULTS: At 40 weeks, rats treated with 1000 ppm sulindac showed narrower esophageal diameter and milder inflammation than the control rats. At 40 weeks, the incidence of Barrett's esophagus was similar between control and sulindac-treated groups, but the incidence of adenocarcinoma was significantly lower in the 1000 ppm sulindac-treated group than either the control or 500 ppm sulindac-treated groups. COX-2 was significantly increased in the lower esophagus of control rats killed at 40 weeks. Cyclin D1 expression was negligible in the sulindac- treated group compared with the control group. CONCLUSION: We suggest that the chemopreventive effect of sulindac is related to decreased COX-2 and cyclin D1 expression, which may be influenced by reduced inflammation.     

Mucinous tubular and spindle cell carcinoma of kidney is probably a variant of papillary renal cell carcinoma with spindle cell features

Mucinous tubular and spindle cell carcinoma is a rare and newly described type of renal cell carcinoma (RCC) with a relatively indolent behavior. However, its histogenetic origin or line of differentiation remains unclear. Twelve cases of mucinous tubular and spindle cell carcinoma were identified and retrieved from the files of 3 institutions. Detailed morphological features, as well as their immunohistochemical profile established with markers of proximal renal tubules (RCC marker antigen, CD15, and alpha-methylacyl-CoA racemase) and of distal renal tubules (kidney-specific cadherin and cytokeratin 7), were studied. The age range of the patients was 35 to 73 years with a median of 56 years. The male to female ratio was 1:3. All of the patients were alive with follow-up between 4 and 38 months. All the tumors were confined to the kidney with a mean tumor size of 6.9 cm (range, 1.8-17 cm). The tumors were composed of variable proportions of tubular and spindle cell areas with focal to prominent mucinous or myxoid stroma. Foamy macrophages were seen in 10 cases and were prominent in 4 cases. A focal compressed tubulopapillary growth pattern was seen in 10 cases. The tumor cells were uniformly cuboidal with ovoid to round nuclei and inconspicuous nucleoli (Furhman nuclear grade 3 in 6 cases). Focal necrosis was seen in 3 cases. Immunostains showed that tumors were positive for RCC marker antigen (11/12), alpha-methylacyl-CoA racemase (11/12), CD15 (8/12), CD10 (2/12), kidney-specific cadherin (1/12), and cytokeratin 7 (11/12). Its morphological features as well as a strong preferential expression of proximal tubule markers suggest that this tumor is a type of RCC with proximal tubular differentiation, which appears closely related to or represents a morphological variant of papillary RCC.     

Accessory gene regulator group polymorphisms in methicillin-resistant Staphylococcus aureus: an association with clinical significance

PURPOSE: Virulent gene expression in Staphylococcus aureus is controlled by regulators such as the accessory gene regulator (agr). Strains can be divided into four major agr groups (agr I-IV) on the basis of agrD and agrC polymorphisms. The purpose of this study was to define the proportion of agr I, II, and III polymorphisms and to compare the clinical characteristics between group I and non-group I polymorphisms of methicillin-resistant Staphylococcus aureus (MRSA) strains in a Korean tertiary care teaching hospital. MATERIALS AND METHODS: A total of 158 clinical isolates were evaluated by RFLPs (restriction fragment length polymorphisms). RESULTS: The mean age of the patients was 50.2 +/- 21.9 years old. There were 74 (49.3%), 66 (44.0%), 10 (6.7%), 7 (4.4%), and 1 (0.6%) strains in agr group I, II, III, I + II, and I + III polymorphisms, respectively. Only ear infections were a statistically significant clinical parameter according to univariate (p=0.001) and multivariate analysis (OR, 4.721 (1.273-17.508), p=0.020). CONCLUSION: This study suggests that agr group I is the most prevalent in Korea, and ear infections are correlated with the group I polymorphism, which is a different clinical trend from western countries. It can also be inferred that community-acquired MRSA correlates with agr group I.