The effect of folic acid deficiency and MTHFR C677T polymorphism on chromosome damage in human lymphocytes in vitro.

We performed a comprehensive study on the genotoxic and cytotoxic effects of in vitro folic acid deficiency on primary human lymphocytes. Lymphocytes were cultured in medium containing 12-120 nM folic acid for 9 days in a novel cytokinesis-block micronucleus (CBMN) assay system (n = 20). Besides identifying optimal folic acid concentrations for in vitro genomic stability, we tested the hypothesis that lymphocytes from individuals homozygous for the C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism (TTs, n = 10) are protected against chromosome damage relative to controls (CCs, n = 10) under conditions of folic acid deficiency. This hypothesis is based on the assumption that reduced MTHFR activity in TT lymphocytes causes a diversion of 5,10-methylene tetrahydrofolate toward thymidine synthesis, which minimizes uracil-induced double-stranded DNA breakage. Cells were scored for micronuclei, apoptosis, necrosis, nucleoplasmic bridges, and nuclear budding. The latter two endpoints are indicative of chromosome rearrangements and gene amplification, respectively, and to the best of our knowledge, this is the first report of their association with folic acid concentration. Folic acid concentration correlated significantly (P < 0.0001) and negatively (r, -0.63 to -0.74) with all markers of chromosome damage, which were minimized at 60-120 nM folic acid, much greater than concentrations assumed "normal," but not necessarily optimal in plasma. Two-way ANOVA revealed no effect of the MTHFR genotype on any of the endpoints. Results show that the C677T polymorphism does not affect the ability of a cell to resist chromosome damage induced by folic acid deficiency in this in vitro system.

Methylenetetrahydrofolate reductase C677T polymorphism does not alter folic acid deficiency-induced uracil incorporation into primary human lymphocyte DNA in vitro.

Methylenetetrahydrofolate reductase (MTHFR) is an enzyme which converts 5,10-methylene tetrahydrofolate (5,10-MnTHF) to 5-methyl tetrahydrofolate. A common C to T transition (C677T) in the MTHFR gene is reported to reduce the risk for colorectal cancer and acute lymphocytic leukemia in homozygotes (TTs). It is hypothesized that because TTs have reduced MTHFR activity, more 5,10-MnTHF is available to provide methyl groups for the conversion of uracil to thymidine. Folic acid deficiency causes the intracellular accumulation of dUMP and the subsequent incorporation of uracil into DNA. The removal of uracil from DNA may result in double-stranded DNA breaks, the accumulation of which is a putative risk factor for cancer. We tested whether human lymphocytes taken from TTs (n = 10) were more able to resist uracil incorporation into DNA than controls (n = 14 CCs and 6 CTs) when cultured in medium containing 12-120 nM folic acid for 9 days. DNA uracil content of these lymphocytes was measured by CG-MS. TTs and controls showed a dose-dependent increase in DNA uracil content during folic acid deficiency (P < 0.0001, R2 = 0.23 for TTs and P < 0.0001, R2 = 0.19 for controls). DNA uracil content was not different between the two groups at any of the folic acid concentrations (two-way ANOVA: media [folic acid], P < 0.0001; genotype, P = 0.4). The results show that, in this in vitro system, the MTHFR C677T polymorphism does not affect the cell's ability to resist uracil incorporation into DNA. Chromosome breakage, as measured by micronuclei, was also shown to correlate with folic acid concentration in a preliminary experiment (P < 0.0001). Although the results appear not to support the hypothesis that a reduced risk for certain cancers in TTs is due to diversion of folic acid to thymidine synthesis, differences between the in vivo and in vitro situation make this conclusion not definitive.

A simpler, more robust method for the analysis of 8-oxoguanine in DNA.

The oxidized DNA base 8-oxoguanine has been commonly measured by enzymatic digestion of DNA to nucleosides followed by high-performance liquid chromatography (HPLC) separation of the adduct 8-oxodeoxyguanosine. There has recently been an enormous debate surrounding the validity of this approach, from which it has become clear that artifactual oxidation of the native base to 8-oxoguanine can occur at numerous stages in sample preparation. Hence, we have designed an alternative protocol to traditional enzymatic digestion of DNA which (i) limits the potential for artifactual oxidation, (ii) speeds up the assay markedly, (iii) increases the assay's sensitivity moderately, and (iv) addresses criticisms that have been raised concerning the efficiency of DNA digestion by nucleases. In short, we use the Escherichia coli repair enzyme formamidopyrimidine (Fapy) glycosylase to release the base 8-oxoguanine from full-length DNA, then separate 8-oxoguanine from high molecular weight molecules by ultrafiltration (10,000 Da exclusion) and analyze the base adduct by reverse-phase HPLC. Benefits of this approach include (i) rapid removal of the roughly million-fold molar excess of unaltered bases from the sample, (ii) reduction in the length of enzymatic incubations and the number of steps, (iii) elimination of high temperature incubation, (iv) a very clean chromatographic separation, and (v) rapid elution of the analyte and correspondingly greater throughput. Using this improved method, we have followed the induction of 8-oxoguanine in the DNA of peroxide-treated HeLa cells, an experiment that had proved cumbersome with traditional methods.

Microsatellite instability and the PTEN1 gene mutation in a subset of early onset gliomas carrying germline mutation or promoter methylation of the hMLH1 gene.

High-frequent microsatellite instability (MSI-H) was detected in two of the 80 gliomas examined, whlie the other 78 gliomas showed microsatellite stable (MSS) phenotype. Both of the two MSI-H tumors were glioblastomas which developed in teenage patients. One of the patient was diagnosed as having Turcot's syndrome and had a germline mutation in the hMLH1 gene. Loss of expression due to promoter methylation was selectively observed in the wild type allele of the hMLH1 gene in the tumor of this patient. The other patient had neither a family history nor a past personal history of malignancy. Although no mutation in the mismatch repair genes was detected in the tumor of this patient, the level of expression of the hMLH1 gene was markedly decreased and the promoter sequence of the gene was highly methylated. In the tumor of this patient, the PTEN1 gene, one of the genes carrying microsatellite sequences in their coding regions, was altered by a slippage mutation within five adenine repeat sequences. These findings indicate that the genetic or epigenentic inactivation of the hMLH1 gene is involved in a subset of early-onset gliomas and the PTEN1 gene could be a downstream target for mutation as observed in glioblastoma without MSI.

[Chronic subdural hematoma associated with malignancy: report of three cases].

Three cases of chronic subdural hematoma (CSH) associated with malignancy are reported. Case 1; A one-year-old girl was referred for vomiting and convulsions. Left CSH was removed, and her symptoms disappeared. Cytological examination of chronic subdural hematoma revealed abnormal white blood cells. A clinical diagnosis of acute monocytic leukemia was made after the laboratory examination. Remission was achieved by chemotherapy, but she died one year after the operation. Case 2; A 72-year-old woman was referred for right hemiparesis and urinary incontinence. Left CSH was irrigated, and her clinical symptoms immediately disappeared. Cytological examination of chronic subdural hematoma revealed abnormal white blood cells. A clinical diagnosis of chronic lymphocytic leukemia was made after the laboratory examination. No treatment was given since there were no clinical symptoms of chronic lymphocytic leukemia. Case 3; A 70-year-old woman who had been affected with early gastric cancer and mammary cancer for the previous two years was admitted to our clinic because of headache, right hemiparesis and consciousness disturbance. Left CSH was irrigated, and her clinical symptoms improved. However, there was a tendency to bleed because disseminated intravascular coagulation had occurred, and CT showed bilateral subdural hematoma. A second irrigation was performed, but her symptoms did not improve. Left acute subdural hematoma, which was removed by craniotomy, occurred three days after the second operation. Pathological examination of the outer membrane of the subdural hematoma revealed invasion of adenocarcinoma. She died three days after the third operation. It is recommended that both the cytological and the histological examinations be performed when possible, since they are simple to perform and very useful in some cases.

The Healthy Neighborhoods Project: a local health department's role in catalyzing community development.

Studies show that community development approaches to health education may lead not only to improved social, economic, and health status but also to increased individual participation in health education and preventive health care activities. However, because of categorical funding restraints and philosophical issues, local health departments have rarely given control of defining project outcomes to the community. One such project was in a low-income urban neighborhood in the San Francisco Bay Area. In this Healthy Neighborhoods Project, the health department catalyzed community development and organization in a multiethnic public housing complex. As a result, an empowered community successfully advocated to improve public safety by installing street speed humps and increased street lighting. After project completion, residents initiated several additional health actions, including the removal of a neighborhood tobacco billboard. This article describes the project, which may serve as a model for other urban public health programs to explore their role in community empowerment.

[A case of thymic carcinoma with brain metastasis].

A 43-year-old female with a thymic carcinoma spreading to the extrathorac region is reported. She had received radiation and chemotherapy, after that thymic carcinoma was extirpated. Five months later, the patient was noticed to have a right side hemiparesis, following consciousness disturbance. CT and MRI revealed a left thalamic mass with a heterogenous enhancement effect. The tumor was diminished dramatically due to radiation. Metastasis of thymic carcinoma to the central nervous system is discussed.

Cloning and characterization of rat cellular nucleic acid binding protein (CNBP) cDNA.

We cloned and sequenced the cDNAs which code for rat cellular nucleic acid binding protein (CNBP). In-frame insertion/deletion differences were found among the clones at two sites in the open reading frame, suggesting alternative splicing of the message or the presence of multiple genes which code for this protein. The deduced amino acid sequence revealed that one rat CNBP sequence was completely identical to its human counterpart. This striking conservation, together with the fact that homologous genes have been found in various organisms including Schizosaccharomyces pombe, suggests that CNBP plays a basic biological role in eukaryotic cells. The recombinant GST-CNBP fusion protein produced in Escherichia coli bound to a G-rich single-stranded RNA and DNA in a sequence-specific manner.

Cloning and characterization of a c-myc intron binding protein (MIBP1).

The cDNA for a c-myc intron 1 binding protein 1 (MIBP1) in the rat was isolated from lambda gt11 and lambda ZAPII cDNA libraries. Sequencing of the cDNA clones revealed a long ORF which encoded a putative protein of 2437 amino acid residues. This protein has two widely separated zinc finger regions, each of which carries C2H2 motifs. When expressed in E. coli as a fusion protein, part of the MIBP1 showed sequence-specific binding to the target sequence, i.e., a 9-bp sequence in the rat c-myc intron 1. MIBP1 is most likely the rat counterpart of human MHC binding protein-2 (MBP-2/HIV-EP2), based on the 86% similarity in nucleotide sequence and 93% similarity in amno acid sequence. Northern blotting revealed a high level of MIBP1 mRNA in the brain.

[A case of intracranial osteochondroma originating with psychomotor epilepsy].

A 28-year-old woman was admitted to our clinic due to psychomotor epilepsy. Craniogram, CT scan demonstrated a calcified lesion in the frontal, parasagittal region. MR proton images showed a mixed hyper-and hypodense lesion. The tumor originated from the frontal bone and was totally removed using airdrill safely. Histological findings revealed osteochondroma originating in the frontal bone is rare, and diagnostic procedures and surgical management of this tumor are discussed.

Cloning and polymerase chain reaction-single-strand conformation polymorphism analysis of anonymous Alu repeats on chromosome 11.

We have shown that many of the Alu repeats found in the GenBank database are polymorphic and that this polymorphism can be detected by a simple technique, single-strand conformation polymorphism (SSCP) analysis, after polymerase chain reaction (PCR) amplification of each repeat from DNA of individuals. Here, we describe a method for collecting many anonymous Alu repeats and their flanks in a chromosome-specific phage library and cloning them into plasmids. The flanking single-copy sequences of each repeat in the plasmid were then determined, and 20mer to 30mer segments of these sequences were used as primers for the PCR-SSCP analysis. Many new polymorphic DNA markers on chromosome 11 were obtained with this method. These markers can also serve as sequence-tagged sites for physical mapping of the genome.

[A case of glioblastoma in which early diagnosis was difficult by MRI].

The authors report a case of glioblastoma in which MR images with Gd-DTPA enhancement changed rapidly during the early stage. A 61 year-old male presented with sudden right facial spasm and dysarthria. However, both a plain and an enhanced CT failed to demonstrate any abnormal lesions. On the other hand, T2 weighted MR image revealed a well circumscribed high intensity lesion in the left frontal lobe without mass effect. This lesion could not be differentiated from cerebral infarction, since no contrast enhanced lesion was able to be observed in T1 weighted MR image with Gd-DTPA. His symptoms gradually became aggravated and at 3 months from the onset, MR image with Gd-DTPA disclosed a small enhanced lesion in the left frontal lobe near the cortical surface. After 6 months from the onset, he suffered from right hemiparesis and motor aphasia. The MR image with Gd-DTPA at this time showed a large enhanced lesion in the left frontal lobe with mass effect. He was admitted to our hospital, and subtotal removal of the tumor and intraoperative radiation was carried out. The patient did well postoperatively without additional neurological deficit, and then he received additional radiation therapy. It should be noted that Gd-DTPA enhanced MR image might fail to reveal the lesion of glioblastoma in its early stage, while T1 weighted image discloses only the gyral swelling.

Detection of p53 gene mutations in human brain tumors by single-strand conformation polymorphism analysis of polymerase chain reaction products.

Single-strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP analysis) was used for detection of mutations of the p53 gene in surgical specimens of human brain tumors. Six of 45 brain tumors showed mobility shifts in the analyses. These six tumors also showed loss of a normal allele. The samples were examined further by direct sequencing. Results showed that four of them had single-base substitutions and the other two had deletions of one and eight base pairs. Five of the six mutations detected were clustered in highly conserved regions of the p53 gene. The frequency of p53 gene mutations in primary brain tumors examined was 9.8%. We also found two new polymorphic markers in the p53 gene, one in intron 7 and the other in an Alu repeat in exon 11. Both markers could be detected by SSCP analysis. Using these two markers, we found two cases of loss of heterozygosity in other brain tumor specimens. Results suggested that aberrations of the p53 gene were not correlated with the malignancy of some types of brain tumors such as anaplastic astrocytoma and glioblastoma, contrary to previous observations on colorectal cancers.

[Effect of X-rays combined with ACNU and O6-ethylguanine on rat subcutaneous gliomas].

Rat gliomas of subcutaneously transplanted RGc-6 cells were irradiated with X-ray either alone, or combined with ACNU, and the cell-survival was assayed in vitro. Cell-survival curve composed of two components by X-irradiation alone indicated the presence of a hypoxic cell fraction. We have previously shown that combined treatment with ACNU apparently made the effect of X-ray on spheroids in vitro of the same cell line of RGc-6 more powerful. Although treatment of rat gliomas with ACNU administered at 2 hrs prior to X-irradiation was most effective, it resulted in only the additive effect of the independent action of the two agents. Further treatment by O6-ethylguanine prior to ACNU administration and X-irradiation apparently increased the strength of the effect of ACNU combined with X-ray to the dose-modifying factor for X-ray of 1.8. The result indicated that the combination of O6-ethylguanine prior to ACNU administration and X-irradiation may clinically enhance the effect of X-ray against apparent ACNU-resistant glioma cells such as RGc-6 cells.

Effects of X-irradiation alone and in combination with ACNU on human glioblastoma cells in vitro.

The combined effects of x-irradiation and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloro-ethyl)-3-nitrosourea (ACNU) on multicellular glioblastoma A-7 spheroids were analyzed by means of cell survival and dose-response curves. The actual dose-response curve for small spheroids was almost identical to that estimated from the cell survival curve. It was strongly suggested that a small number of radiation-resistant cells, which were not detected in the cell survival curve, were present in large spheroids with central necrosis. The enhancing effect of ACNU was greater with large spheroids than with monolayer cells or small spheroids. A possible explanation for this is that ACNU is higher effective against the few radiation-resistant cells that may be present in larger spheroids.

[Enhancement of the effect of X-irradiation against cultured human glioblastoma cells by pretreatment with ACNU].

Human glioblastoma A-7 (GB A-7) cells can apparently recover from potentially lethal X-irradiation. The authors, using a colony-forming assay, studied the influence of pretreatment with 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) on the effectiveness of X-irradiation against GB A-7 cells grown in monolayers and as multicellular spheroids. Pre-exposure to ACNU inhibited the recovery of irradiated GB A-7 cells. In monolayer cells, the combination treatment was most effective when ACNU was applied 2 to 8 hours prior to irradiation, and the larger the X-ray dose, the more potent the effect. ACNU pretreatment was more effective against large spheroids (enhancement ratio 1.86) than against small ones (1.34). Large spheroids showed necrosis, whereas small ones did not. Isobolographic analysis disclosed that the effect of combining X-irradiation and ACNU is within an additive envelope at the surviving fraction of 10(-2), while supra-additive at the surviving fraction of 10(-3). These results suggest that the potency of X-irradiation is augmented by ACNU pretreatment through an interactive mechanism. Further, suppression of recovery from X-ray induced potentially lethal damage was influenced by the presence of necrosis.

[Cerebral cysticercosis: a case report with special reference to CT and MRI findings].

A case of cerebral cysticercosis was reported with special reference to CT and MRI findings. A 51-year-old man, who had traveled to Taiwan in 1984, was admitted to the hospital for further examination concerning right hemiconvulsion, on January 23, 1988. On admission, a slightly euphoric state and Foster Kennedy syndrome (left: optic atrophy, right: choked disc) were observed. CT scan revealed multiple cystic lesions with ring-like enhancement around basal cisterns. MRI showed intensity of cyst contents parallel to CSF (on T1 and T2 weighted images) and high intensity rim around the cysts (especially on T2 weighted image). An operation was performed and the cysts were almost totally removed. The cyst was confirmed pathologically as cysticercosis, but no scolex was found in it. Postoperative immunological study on the serum and CSF was negative. In the diagnosis of atypical cystic lesions around basal cisterns, cerebral cysticercosis, rare in Japan, should also be considered, and it was emphasized that MRI was very useful for the diagnosis of such cysts.

[Duplicate origin of vertebral artery combined with brain tumor].

A 59-year-old woman was admitted to our hospital with complaints of disturbance of consciousness. CT scan revealed right ventricular tumor, which was homogenously enhanced by contrast media. Left vertebral angiogram demonstrated a duplicated origin of vertebral artery. Right ventricular tumor, which was diagnosed choroid plexus carcinoma histologically, was successfully removed. Nine cases of duplicate origin of vertebral artery were analyzed from the literature. Our reported case was first brain tumor case with duplicate origin of vertebral artery.

[Biological basis for combined radio-chemotherapy in radioresistant tumors].

Human tumor cells such as melanoma or glioblastoma are intrinsically radioresistant on an average than cells of more common tumors in radiotherapy such as squamous cell carcinoma or adenocarcinoma. Mean inactivation dose (D) for glioblastoma A-7 cells was 3.1 Gy for cells growing exponentially, but was 4.3 Gy for cells grown in large spheroids with hypoxic cells and PLD recovery. The D for cells of squamous cell carcinoma was about 2.1 Gy. This indicates that local control of the radioresistant tumors may be achieved if a drug showing an enhancement ratio of about 2.0. Data on our experiments with others in the literature indicate that drugs which selectively sensitize hypoxic cells and inhibit PLD recovery may be useful to increase the therapeutic ratio. Experimental evidence on a nitrosourea, ACNU has been presented for such mechanisms of the action. Multivariate analysis with Cox's model on malignant gliomas of 209 patients indicated that a significant increase in the survival time was obtained in the radiotherapy combined with ACNU.

[Multiple meningiomas with Werner's syndrome--a case report].

A case of multiple meningiomas with Werner's syndrome is reported. He was 45-year-old man, who complained change of character and slight right motor weakness for 4 months. His symptoms were characteristic small stature, premature senility, scleroderma-like changes and other manifestations. Glucose tolerance test showed a diabetic pattern. CT scan and cerebral angiography revealed multiple meningiomas. After chemical embolization of the feeding artery, we removed these meningiomas successfully. We also reviewed the literature on Werner's syndrome with meningioma.