Involvement of Krüippel-like factor 6 （KLF6） mutation in the development of nonpolypoid colorectal carcinoma

AIM： To examine Kruppel-like factor 6 （KLF6） mutations in nonpolypoid-type tumors and alterations of K-ras, p53, and B-raf in relation between mutation and morphologic type, particularly nonpolypoid-type colorectal carcinomas.
METHODS： Fifty-five early nonpolypoid colorectal carcinomas were analyzed. Loss of heterozygosity （LOH） of KLF6 and p53 was determined by microsatellite assay. Mutations of KLF6, K-ras, and B-raf were examined by polymerase chain reaction-single-strand conformation polymorphism followed by direct sequencing. In LOH- positive and/or mutation-positive tumors, multiple （4-7） samples in each tumor were microdissected and examined for genetic alterations, p53 expression was evaluated by immunohistochemistry. RESULTS： LOH of KLF6 and p53 was found in 14 of 29 （48.3%） and 14 of 31 （45.2%） tumors, respectively. In tO of the 14 （71.4%） KLF6 LOH-positive tumors and 9 of the 14 （64.3%） p53 LOH-positive tumors, LOH was found in all of the microdissected samples. In 1 of the tO （10.0%） KLF6 LOH-positive tumors, a single missense mutation was identified. K-ras and B-raf mutations were found in 5 of 55 （9.1%） and 6 of 55 （10.9%） tumors, respectively. However, these mutations were detected only in subsets of microdissected tumor samples.
CONCLUSION： These data suggest that KLF6 and p53 mutations are involved in the development of nonpolypoid colorectal carcinoma, whereas K-ras and B-raf mutations are not.     

Correlation of N-myc downstream-regulated gene 1 expression with clinical outcomes of colorectal cancer patients of different race/ethnicity

AIM: To evaluate the role of N-myc downstream-regulated gene 1 (NDRG1) expression in prognosis and survival of colorectal cancer patients with different ethnic backgrounds. METHODS: Because NDRG1 is a downstream target of p53 and hypoxia inducible factor-1α (HIF-1α),we examined NDRG1 expression together with p53 and HIF-1α by immunohistochemistry. A total of 157 colorectal cancer specimens including 80 from Japanese patients and 77 from US patients were examined. The correlation between protein expression with clinicopathological features and survival after surgery was analyzed.in colorectal tumor compared with normal epithelium in both Japanese and US patient groups. Expression of NDRG1 protein was significantly correlated with lymphatic invasion,venous invasion,depth of invasion,histopathological type,and Dukes' stage in Japanese colorectal cancer patients. NDRG1 expression was correlated to histopathological type,Dukes' stage and HIF-1α expression in US-Caucasian patients but not in US-African American patients. Interestingly,Kaplan-Meier survival analysis demonstrated that NDRG1 expression correlated significantly with poorer survival in US-African American patients but not in other patient groups. However,in p53-positive US cases,NDRG1 positivity correlated significantly with better survival. In addition,NDRG1 expression also correlated significantly with improved survival in US patients with stages Ⅲ and Ⅳ tumors without chemotherapy. In Japanese patients with stages Ⅱ and Ⅲ tumors,strong NDRG1 staining in p53-positive tumors correlated significantly with improved survival but negatively in patients without chemotherapy. CONCLUSION: NDRG1 expression was correlated with various clinicopathological features and clinical outcomes in colorectal cancer depending on the race/ethnicity of the patients. NDRG1 may serve as a biological basis for the disparity of clinical outcomes of colorectal cancer patients with different ethnic backgrounds.     

Selective decrease in colonic CD56^＋ T and CD161^＋ T cells in the inflamed mucosa of patients with ulcerative colitis

AIM： To investigate the role of local colonic mucosal NK receptor-positive T （NKR＋ T） cells in the regulation of intestinal inflammation, we analyzed the population and function of these cells in ulcerative colitis （UC）. METHODS： Colonic mucosal tissues were obtained from colonoscopic biopsies of the descending colon from 96 patients with UC （51 endoscopically uninflamed, 45 inflamed） and 18 normal controls. Endoscopic appearance and histologic score at the biopsied site were determined by MaLts＇ classification. A single cell suspension was prepared from each biopsy by collagenase digestion. Two NKR^＋ T cell subsets, CD56^＋ （CD56^＋CD3^＋） T cells and CD161＋ （CD161^＋CD3^＋） T cells, were detected by flow cytometric analysis. Intracellular cytokine analysis for anti-inflammatory cytokine interleukin-10 （IL-10） was performed by in vitro stimulation with phorbol-myristateacetate （PMA） and ionomycin. RESULTS： CD56^＋ T cells and CD161^＋ T cells are present in the normal human colon and account for 6.7% and 21.3% of all mononuclear cells, respectively. The populations of both CD56＋ T cells and CD161^＋ T cells were decreased significantly in the inflamed mucosa of UC. In contrast, the frequency of conventional T cells （CD56 CD3^＋ cells and CD161CD3^＋ cells） was similar among the patient and control groups. The populations of NKR^＋ T cells were correlated inversely with the severity of inflammation, which was classified according to the endoscopic and histologic Marts＇ criteria. Interestingly, approximately 4% of mucosal NKR＋ T cells expressing IL-10 were detected by in vitro stimulation with PMA and ionomycin.CONCLUSION： Selective reduction in the population of colonic mucosal NKR＋T cells may contribute to the development of intestinal inflammation in UC.     

Decitabine--bedside to bench

PURPOSE OF THE REVIEW: Epigenetic changes marked by DNA methylation are known to contribute to the malignant transformation of cells by silencing critical genes. Decitabine inhibits DNA methyltransferase and has shown therapeutic effects in patients with hematologic malignancies. However, the connection between the clinical activity of decitabine and its demethylating activity is not clear. Herein, we summarize the results of recent clinical trials of decitabine in hematologic malignancies, and review the translational research into decitabine's mechanism of clinical activity. RECENT FINDINGS: Low-dose decitabine has been studied recently in multiple clinical trials and has been shown to be effective for treatment of myelodysplastic syndromes. Correlative laboratory studies of clinical trials have shown that decitabine induces global hypomethylation as well as hypomethylation of gene-specific promoters and activation of gene expression. Past a given threshold, induction of higher degrees of hypomethylation is not directly associated with a better clinical outcome. Moreover, studies have suggested that patients with promoter hypermethylation of p15(INK4B) at baseline have paradoxically a lower chance of achieving response than those without hypermethylation. Furthermore, several other genes activated by decitabine were independent of hypomethylation in the promoter regions. CONCLUSION: While at least part of decitabine's activity is through induction of hypomethylation and reactivation of critical genes, mechanisms independent from hypomethylation are also important for decitabine's antitumor activity.     

Thalamic hypometabolism on 18FDG-positron emission tomography in medial temporal lobe epilepsy

OBJECTIVES: Degree of hypometabolism in the thalamus on (18)Fluorodeoxyglucose-positron emission tomography (FDG-PET) was compared with those of medial and lateral temporal lobes in patients with medial temporal lobe epilepsy (mTLE), and its relationship with post-operative seizure outcomes was investigated. METHODS: Twenty-six patients with mTLE who underwent anterior temporal lobectomy were included. Post-operatively, 13 patients became completely seizure-free and 13 showed residual seizure, regardless of frequency (five patients became almost seizure-free, six had rare seizures and two showed significant improvements). Degrees of hypometabolism in bilateral thalamus, ipsilateral medial and lateral temporal lobes were evaluated visually and semi-quantitatively by determining the asymmetry index (AI), a value indicating 100 x (ipsilateral - contralateral)/[1/2 x (ipsilateral + contralateral)] and the region-to-cerebral hemisphere ratio (R/C ratio) being the ratio between averaged counts in each area and those in the cerebral hemisphere of the same side. RESULTS: Hypometabolism in the medial temporal lobe was visually observed in all patients. Hypometabolism in the lateral temporal lobe was observed in 20 patients and was semi-quantitatively more prominent than that of the medial temporal lobe. Pathologically, hippocampal sclerosis and prominent astrogliosis of the lateral temporal lobe were present in all cases. However, while thalamic hypometabolism was visually observed in nine patients (in the ipsilateral side of four cases, contralateral side of three and on both sides of two), no significant thalamic hypometabolism was semi-quantitatively observed. No significant differences in metabolic rate in any area except for the lateral temporal lobe between seizure-free patients and residual seizure patients were seen semi-quantitatively. DISCUSSION: Data indicated that metabolism in the lateral temporal lobe of patients with mTLE significantly decreased and revealed pathologic glial changes. Thalamic hypometabolism was quite mild and did not correlate with post-operative seizure outcome.     

Involvement of thrombin and mitogen-activated protein kinase pathways in hemorrhagic brain injury

Thrombin is thought to play an important role in brain damage associated with intracerebral hemorrhage (ICH). We previously showed that activation of mitogen-activated protein (MAP) kinases and recruitment of microglia are crucial for thrombin-induced shrinkage of the striatal tissue in vitro and thrombin-induced striatal damage in vivo. Here we investigated whether the same mechanisms are involved in ICH-induced brain injury. A substantial loss of neurons was observed in the center and the peripheral region of hematoma at 3 days after ICH induced by intrastriatal injection of collagenase in adult rats. Intracerebroventricular injection of argatroban or cycloheximide, both of which prevent thrombin cytotoxicity in vitro, exhibited a significant neuroprotective effect against ICH-induced injury. ICH-induced neuron loss was also prevented by a MAP kinase kinase inhibitor (PD98059) and a c-Jun N-terminal kinase inhibitor (SP600125). These drugs had no effect on hematoma size or ICH-induced brain edema. Activation of extracellular signal-regulated kinase in response to ICH was observed in both neurons and microglia. Despite their neuroprotective effects, MAP kinase inhibitors did not decrease the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells appearing after ICH. Identification of cell types revealed that TUNEL staining occurred prominently in neurons but not in microglia, whereas inhibition of MAP kinases resulted in appearance of TUNEL staining in microglia. These results suggest that thrombin and the activation of MAP kinases are involved in ICH-induced neuronal injury, and that neuroprotective effects of MAP kinases are in part mediated by arrestment of microglial activities.     

Intravenous immunoglobulin therapy markedly ameliorates muscle weakness and severe pain in proximal diabetic neuropathy

A 57-year-old man with type 2 diabetes mellitus for 10 years showed progressive loss of muscle strength in both legs, pain and muscle atrophy in the femoral region and significant weight loss. On admission, he could not stand alone and used a wheelchair. He also complained of severe pain in the lower extremities. He was diagnosed with proximal diabetic neuropathy (PDN) by characteristic clinical and electrophysiological features. Intravenous immunoglobulin therapy (IVIg 0.4 g/kg x 5 days) markedly reduced the severe pain and muscle weakness in the legs. Eventually, pain assessed by the Visual Analogue Scale was relieved by 80% and muscle strength was also well recovered, thereby enabling the patient to walk with a cane. The present case suggests that IVIg therapy may be effective for the relief of pain in PDN.     

Post-licensed 1-year experience of systemic thrombolysis with tissue plasminogen activator for ischemic stroke in a Japanese neuro-unit

OBJECTIVE: In Japan, intravenous thrombolysis with tissue plasminogen activator (tPA) for ischemic stroke within 3h of onset was officially approved in October 2005. METHODS: We report initial 1-year clinical experience of intravenous alteplase at 0.6mg/kg in a Japanese neuro-unit. RESULTS: Twenty patients received intravenous tPA, corresponding to 12% of all ischemic strokes (n=166) and 38% of ischemic strokes within 3h of onset (n=52). The mean age was 68 years old and 15% had pre-morbid dependency with modified Rankin Scale (mRS) of 3 or 4. The median baseline National Institute of Health Stroke Scale score was 19 points (range; 5-37). Average time from stroke onset to tPA delivery was 136 min (range; 87-180). Of 18 (90%) patients receiving pretreatment vascular imaging, 16 (80%) patients had a large arterial occlusion. At 3 months, excellent outcome with mRS of 0 or 1 was 25%, and good outcome with mRS of 0-2 was 35%. One patient (5%) developed symptomatic intracranial hemorrhage within 36 h. Mortality rate was 15%. CONCLUSIONS: Intravenous tPA within 3h was safe and feasible, and possibly effective in clinical practice. The higher stroke severity in our cohort precluded to compare the sufficient effectiveness with clinical trials. In Japan, a post-licensed national surveillance is currently under way.     

Prevalence and features of migraine in Japanese junior high school students aged 12-15 yr

Migraine is the most common cause of recurrent headache among children and adolescents resulting in missing of school and disabling their daily life. The purpose of this study is to determine the prevalence and clinical features of headache in junior high school children in Japan. In December 2004, questionnaires were sent to 14 junior high schools. There were multiple-choice type questions on headache, mainly migraine. The questionnaires were given during school hours, and 6472 answers were obtained. One thousand four hundred seventy-eight (22.8%) students experienced severe headache and 476 (7.4%) had consulted physicians. Three hundred thirteen (4.8%) were identified as having migraine based on the ICHD-II criteria, consisting of 110/3346 boys (3.3%) and 203/3126 girls (6.5%): 91 (29.1%) with aura and 222 (70.9%) without aura. In about half of the children the migraine attacks were of short duration, ranging from 1 to 3 h. There were 36 boys (1.1%) and 45 girls (1.4%) who had shorter attacks of less than 1 h, whom we did not diagnose as having migraine according to the ICHD-II criteria. Although migraine is common among schoolchildren, it is often under- or miss-diagnosed since the clinical figure for childhood migraine differs from that for adults.