In the development of colorectal cancer (CRC), it is now widely accepted that some forms of genetic instability lead to the sequential accumulation of genetic alterations and consequently develop carcinomas. 1 RAS activation in the MAP kinase cascade is supposed to constitute a part of the primary events in colorectal carcinogenesis, and the KRAS gene mutations have been found in about 30 -40% cases of sporadic CRCs. [2][3][4] Recently, activating BRAF mutations have been found almost invariably in melanoma cells and sometimes in other types of carcinoma, including CRCs, 5-7 implying a function of BRAF as a protooncogene. The RAF genes are members of MAPK pathway, encoding serine/threonine kinases that integrate the upstream input signals. 8,9 Once recruited at the cell membrane by GTP-loaded RAS, RAF becomes activated and subsequently phosphorylates the downstream kinases, MEKs, which eventually induce transcriptional activation of the target genes. 9 More recently, frequent BRAF mutations and infrequent KRAS mutations have been reported in DNA-mismatch repair (MMR)-deficient CRCs. 10 Inactivation of MMR genes incurs instability of genomic microsatellite sequence (microsatellite instability, or MSI), which is found in the majority of patients with hereditary nonpolyposis colorectal cancer syndrome (HNPCC) and in 10 -15% of cases of sporadic CRCs. 11-13 Moreover, it was also reported that 70 -90% of sporadic CRCs with MSI (MSI ϩ CRCs) are associated with hypermethylation of hMLH1, one of DNA-MMR genes, and have distinct clinical and pathologic characteristics, i.e., occurrence in older females, location in the proximal colon and histopathology of mucious or poor differentiation. 14 -20 We have previously examined the methylation status of hMLH1 gene in sporadic CRCs by use of 5 sets of primer spanning the whole CpG sites within its promoter region and have classified the methylation status into 3 subtypes: full methylation, partial methylation and nonmethylation. 21,22 We reported that an extensive methylation, or full methylation, of hMLH1 promoter was found in about 80% of MSI ϩ CRC cases and was highly associated with loss of expression of its gene product. Interestingly, this type of CRC cells are rarely associated with KRAS mutations and loss of heterozygosity (LOH) of TP53 gene. 22 It is therefore possible that extensive methylation of hMLH1 promoter region may contribute to the carcinogenesis of the right-sided sporadic CRCs, independently of KRAS/p53 alterations.From these results, 2 questions may arise. First, does the activation of BRAF, instead of KRAS, take part in the carcinogenesis of CRCs with extensive hMLH1 methylation? Second, if so, does the BRAF activation have any relationship with the CRCs with partial methylation, although most of which are microsatellite stable (MSI Ϫ ), maintain MMR gene expression and show a relatively high incidence of KRAS and p53 alterations? 22 Additionally, in the melanoma cells, high frequency of mutations of ␤-catenin and BRAF has been recognized. 23 Some resea...

A multi-institutional collaborative study was conducted concerning the course of pregnancy and delivery and the incidence of abnormal infants delivered of epileptic women. Of 657 women receiving antiepileptic drugs, 73% delivered live infants, 14% had miscarriage or stillbirth, and 13% underwent induced abortion. In contrast to the above findings, 80% of 162 patients not receiving antiepileptic drugs delivered live infants and 4% had miscarriage or stillbirth. The latter outcome was significantly increased in the medicated patients. In this series, 63 (9.9%) of 638 live births were malformed, 55 (11.5%) being from medicated mothers and 3 (2.3%) from nonmedicated mothers. The incidence of fetal malformation in medicated mothers was thus five times as high as that in nonmedicated mothers. Cleft lip and/or palate and malformations involving the cardiovascular system were found frequently in the infants from medicated mothers. General background factors that might exert teratogenic effects on pregnant patients with epilepsy were studied, and the potential toxicity of antiepileptic drugs to the fetus was also analyzed. In this regard, consideration should be given to whether the patient has partial epileptic seizures, whether the patient herself exhibits any malformation, or whether her previous pregnancy resulted in an abnormal outcome. The incidence of fetal malformation was the highest (12.7%) in the medicated patients who had epileptic seizures during the pregnancy. It is presumed on the basis of the results of analysis of the data that a combination of more than three drugs and a daily dose greater than a certain minimal level is likely to produce malformed infants.

Mutation or epigenetic silencing of mismatch repair genes, such as MLH1 and MSH2, results in microsatellite instability (MSI) in the genome of a subset of colorectal carcinomas (CRCs). However, little is yet known of genes that directly contribute to tumor formation in such cancers. To characterize MSI-dependent changes in gene expression, we have now compared transcriptomes between fresh CRC specimens positive or negative for MSI (n ¼ 10 for each) with the use of high-density oligonucleotide microarrays harboring >44 000 probe sets. Correspondence analysis of the expression patterns of isolated MSI-associated genes revealed that the transcriptome of MSI þ CRCs is clearly distinct from that of MSI À CRCs. Such MSI-associated genes included that for AXIN2, an important component of the WNT signaling pathway. AXIN2 was silenced, apparently as a result of extensive methylation of its promoter region, specifically in MSI þ CRC specimens. Forced expression of AXIN2, either by treatment with 5 0 -azacytidine or by transfection with AXIN2 cDNA, resulted in rapid cell death in an MSI þ CRC cell line. These data indicate that epigenetic silencing of AXIN2 is specifically associated with carcinogenesis in MSI þ CRCs.

Summary. Myelodysplastic syndrome (MDS) is a clonal disorder of haematopoietic stem cells. Despite the high incidence of MDS in the elderly, effective treatment of individuals in its advanced stages is problematic. DNA microarray analysis is a potentially informative approach to the development of new treatments for MDS. However, a simple comparison of 'transcriptomes' of bone marrow mononuclear cells among individuals at distinct stages of MDS would result in the identification of genes whose expression differences only reflect differences in the proportion of MDS blasts within bone marrow. Such a 'population shift' effect has now been avoided by purification of haematopoietic stem-like cells that are positive for the cell surface marker AC133 from the bone marrow of healthy volunteers and 30 patients at various stages of MDS. Microarray analysis with the AC133 + cells from these individuals resulted in the identification of sets of genes with expression that was specific to either indolent or advanced stages of MDS. The former group of genes included that for PIASy, which catalyses protein modification with the ubiquitin-like molecule SUMO. Induction of PIASy expression in a mouse myeloid cell line induced apoptosis. A loss of PIASy expression may therefore contribute directly to the growth of MDS blasts and stage progression.

Data from patients in Japan was analyzed to examine the age distribution and differences by age in the clinical manifestations of influenza-associated encephalopathy. Between 1998 and 2002, 472 cases of influenza-associated encephalopathy in patients aged 15 years or younger were reported to the Collaborative Study Group on Influenza-Associated Encephalopathy. These cases were divided into two groups by age: 0-5 and 6-15 years. The differences between the groups were estimated based on the data for those aged 0-5 years, and the odds ratios and 95% confidence intervals calculated. Distribution was inversely correlated with age, with a peak at 1-2 years old. In comparison with patients aged 0-5, those aged 6-15 years had a significantly greater incidence of type B infection, lower frequency of convulsions, higher frequency of loss of consciousness and altered consciousness as the initial neurological symptom, lower serum transaminase levels, lower frequency of low-density area for brain CT upon admission, and lower incidence of sequelae. Our analysis indicates that the clinical course, laboratory data, and brain imaging findings of influenza-associated encephalopathy exhibits patterns that vary with age.