DNA methylation and sensitivity to antimetabolites in cancer cell lines

The prediction of the cellular direction of metabolic pathways toward either DNA synthesis or DNA methylation is crucial for determining the susceptibility of cancers to anti-metabolites such as fluorouracil (5-FU). We genotyped the methylenetetrahydrofolate reductase (MTHFR) gene in NCI-60 cancer cell lines, and identified the methylation status of 24 tumor suppressor genes using methylation-specific multiplex ligation-dependent probe amplification. The susceptibility of the cancer cell lines to seven antimetabolites was then determined. Cells homozygous for CC at MTHFR-A1298C were significantly more sensitive to cyclocytidine, cytarabine (AraC) and floxuridine than those with AA or AC (p=0.0215, p=0.0166, and p=0.0323, respectively), and carried more methylated tumor suppressor genes (p=0.0313). Among the 12 tumor suppressor genes which were methylated in >25% of cancer cell lines, the methylation status of TIMP3, APC and IGSF4 significantly correlated with sensitivity to pyrimidine synthesis inhibitors. In particular, cells with methylated TIMP3 had reduced mRNA levels and were significantly more sensitive to aphidicolin-glycinate, AraC and 5-FU than cells with unmethylated TIMP3. We speculate that MTHFR-A1298C homozygous CC might direct the methylation rather than the synthesis of DNA, and result in the methylation of several tumor suppressor genes such as TIMP3. These genes could be useful biological markers for predicting the efficacy of antimetabolites.     

Positive KL-6 mucin expression combined with decreased membranous beta-catenin expression indicates worse prognosis in colorectal carcinoma

Interaction of MUC1 with beta-catenin plays a significant role in tumor progression and invasion. However, the clinical significance of coexpression of MUC1 and subcellular beta-catenin expression in colorectal carcinoma remains unclear. The present study evaluated the clinicopathological significance of their combined expression for predicting prognosis. Seventy-seven colorectal carcinomas were subjected to immunohistochemical staining with anti-MUC1 KL-6 mucin and anti-beta-catenin monoclonal antibody. Positive KL-6 mucin expression was correlated with decreased membranous beta-catenin expression (P=0.022), while no correlation was found between positive KL-6 expression and nuclear beta-catenin expression (P=0.142). Preservation of membranous beta-catenin expression was detected in 35 cases (45.5%) and decreased membranous beta-catenin expression was found in 42 cases (54.5%). Negative KL-6 expression was detected in 31 cases (41.3%) and positive expression was seen in 46 cases (59.7%). Combined positive KL-6 expression and decreased membranous beta-catenin expression was found in 30 patients (39.0%), whose survival was significantly worse than that of patients with other expression patterns for these two molecules (53.3 vs. 84.4%, P=0.005). Multivariate analysis showed that this combination was as an independent predictor of survival. We concluded that the combined pattern of positive KL-6 expression and decreased membranous beta-catenin expression by colorectal carcinoma is a useful biomarker for distinguishing a subgroup of patients with a worse prognosis.     

Thinning of ventricular septum in tetralogy of Fallot]

Cross sectional echocardiography was used to evaluate the thickness of the ventricular septum in tetralogy of Fallot (TOF). Forty-six patients with TOF and 20 patients with pseudo-truncus arteriosus underwent echocardiography during a five-year period beginning in 1984. Thicknesses of the right ventricular anterior wall (RVAWT), trabecular septum (IVST) and left ventricular posterior wall (LVPWT) were measured in end diastole on parasternal short axis view at the level of the tips of papillary muscles. The ratios of IVST to RVAWT and IVST to LVPWT were assessed. The ratio of IVST to RVAWT was 1.09 +/- 0.15 in the group aged less than 7 years (less than 7 y.o.) and 0.94 +/- 0.15 in the group aged of 7 years or more (greater than = 7 y.o.). The ratios of IVST to LVPWT were 1.10 +/- 0.14 (less than 7 y.o.) and 0.90 +/- 0.15 (greater than = 7 y.o.), respectively. Both ratios were significantly different (p less than 0.01) in the two age groups, and relative thinning of the septum was demonstrated in the older patients. It is speculated that thinning of the interventricular septum is caused by the lower systolic wall stress of the ventricular septum compared with that of the free walls, which is produced under equal systolic pressure of the two ventricles. It is suggested that this thinning is one of the factors that reduces left ventricular function after repair of TOF.     

Bradykinin-induced release of thromboxane B2 into bronchoalveolar lavage fluid of guinea pigs: relationship to airflow obstruction

The aim of this study was to evaluate the role of thromboxane A₂ in bradykinin-induced airflow obstruction in guinea pig in vivo. Airway insufflation pressure (P_i) was measured to assess airflow obstruction and the thromboxane B₂ (a stable metabolite of thromboxane A₂) concentration in bronchoalvelolar lavage fluid was determined by radioimmunoassay. The animals were pretreated with propranolol (1 mg/kg i.v.) and suxamethonium (5 mg i.v.) prior to bradykinin administration. Bradykinin instillation into the trachea (300 nmol) induced a P_i increase (47.5 ± 8.3 cm H₂O versus 23.8 ± 1.5 in sham) and significant thromboxane B₂ release into bronchoalveolar lavage fluid (79 ± 19 pg/ml versus 19 ± 6 in sham). A thromboxane synthase inhibitor (OKY-046, 30 mg/kg i.v.; ((E-E)-3-[p(1H-imidazole-1-yl-methyl) phenyl]-2-propenoic acid hydrochloride mono-hydrate)) or a thromboxane A₂ receptor antagonist (ICI192,605, 0.5 mg/kg i.v.; (4-(Z)-6-(2-o-chloro-phenyl-4-o-hydroxyphenyl-1,3-dioxan-cis-5-yl)hexenoic acid)) reduced the P_i increase evoked by bradykinin (38.7 ± 3.8 and 40.6 ± 3.8 cm H₂O, respectively). OKY-046 abolished the thromboxane B₂ release. A platelet-activating factor receptor antagonist, WEB2086 (1 mg/kg i.v.; (3-[4-(chlorophenyl)-9-methyl-6H-thienol [3,2-f][1,2,4]trizolo-[4,3-a][1,4] diazepin-2-yl]1-4-(4-morpholinyl)-1-propanon) did not significantly affect any measured parameter. We conclude that, in guinea pigs, bradykinin-induced airway effects are associated with a local thromboxane A₂ release.     

Percutaneous Penetration of Acyclovir Through Excised Hairless Mouse and Rat Skin: Effect of Vehicle and Percutaneous Penetration Enhancer

The effects of vehicle and percutaneous penetration enhancer on the penetration of acyclovir through excised hairless mouse and rat skin were investigated. Four solvents, propylene glycol (PG), ethanol (ET), isopropanol (IPA), and isopropyl myristate (IPM), were employed as vehicles, in combination with four enhancers, l-farnesylazacycloheptan-2-one (7FU), l-geranylazacycloheptan-2-one (7GU), l-geranylazacyclopentan-2-one (5GU), and l-dodecylazacycloheptan-2-one (Azone). Acyclovir was suspended in vehicles to avoid the effect of the thermodynamic activity of acyclovir in the vehicle. The penetration of acyclovir through hairless mouse skin from IPA was enhanced by 7GU, whereas that from IPM was not affected. All combinations of vehicle and penetration enhancer were examined using rat skin. No effect of the enhancers was observed in the IPM vehicle. The estimated solubility parameters of vehicles and enhancers indicated that the polarities of IPM and the enhancers are similar, which prevents effective penetration of the enhancers from IPM. However, the penetration of acyclovir from the other vehicles was increased by the enhancers. The combination of hydrophilic vehicle and hydrophobic enhancer resulted in a large enhancing effect. The disappearance of the enhancers from the vehicle correlated with their enhancing activity, but other factors also seemed to affect the penetration enhancement of acyclovir.     

Correlation between blood prostaglandins and blood pressure in chronic renal failure

Plasma prostaglandins (PGs; PGE2, PGF2 alpha, 6-keto-PGF 1 alpha and TXB2) and plasma renin activity (PRA) were measured in 94 end-stage renal disease (ESRD) patients including 15 undialyzed, 74 maintenance-hemodialyzed and 5 anephric patients, and in 27 healthy controls. In the healthy controls, 6-keto-PGF 1 alpha inversely correlated with age, while TXB2 and the TXB2/6-keto-PGF 1 alpha ratio correlated with age. In the ESRD patients, 6-keto-PGF 1 alpha showed a tendency to decrease with age, and the TXB2/6-keto-PGF 1 alpha ratio significantly correlated with age. The undialyzed group showed significantly higher blood pressure and TXB2 but significantly lower 6-keto-PGF1 alpha compared to the other groups. In the dialyzed group, PGE2 and 6-keto-PGF1 alpha tended to be lower and TXB2 higher compared to the healthy control group. In the dialyzed group, 6-keto-PGF1 alpha correlated inversely with blood pressure independently from PRA. As for PGF2 alpha, it was higher in the undialyzed, dialyzed and anephric groups than in the healthy control group. These results suggested that PGs were involved in blood pressure abnormalities, and that PGI2 played an important role in controlling blood pressure in ESRD patients as one of the depressor factors.     

Alterations of nitrite and nitrate concentrations in the blood of mice exposed to nitrogen dioxide

Blood nitrite and nitrate of mice were determined using naphthylethylenediamine and a Cu-Cd reduction column. When mice were exposed to 40 ppm nitrogen dioxide, nitrite became constant in 10 min. Nitrite declined rapidly, with a half-life of several minutes, when mice were removed to room air. Nitrate showed changes similar to those of nitrite; however, the concentration in the blood was higher and the half-life was longer. Dose-effect relationships were also determined at concentrations ranging between 5 and 40 ppm for 1 hr exposure. No increase of methemoglobin was observed at these concentrations. Addition of fresh mouse blood to sodium nitrite in vitro indicated a rapid conversion of nitrite to nitrate with an increase of methemoglobin, whereas addition to sodium nitrate did not cause any changes. The fate of inhaled nitrogen dioxide in the living body is discussed based on the results obtained.     

An immunohistochemical study of intracranial germ cell tumours

Summary Histologically verified intracranial tumours, mainly germ cell tumours of the pineal and suprasellar regions, were studied immunohistochemically using anti-serum of alpha fetoprotein (AFP), human chorionic gonadotropin (HCG), carcinoembryonic antigen (CEA), human placental lactogen (HPL), pregnancy specific -1 glycoprotein (SP-1), glial fibrillary acidic protein (GFAP), S-100 and neuron specific enolase (NSE). In germinomas, HCG positive cells were occasionally demonstrated in cells presenting as syncytiotrophoblastic giant cells (STGC), and GFAP and S-100 positive cells were found in the surrounding gliotic lesions. Teratomas were positive for CEA in their epithelial components. Endodermal sinus tumours were positive for AFP, choriocarcinomas for HCG and SP-1, and embryonal carcinomas for AFP, HCG and SP-1. HCG and SP-1 positive cells were demonstrated in STGC. As for the relationship between serum AFP level and tissue localization, many cases presenting a serum AFP level exceeding 220 ng/ml were positive for AFP in tumour tissue.     

Awake surgery for glioblastoma can preserve independence level,but is dependent on age and the preoperative condition

Journal of Neuro-Oncology - Lately, awake surgery has been frequently adapted for glioblastoma (GBM). However, even with awake surgery, the expected long-term independence levels may not be...