Dark Blood Contrast-Enhanced Brain MRI Using Echo-uT1 RESS.

BACKGROUND: The widely used magnetization-prepared rapid gradient-echo (MPRAGE) sequence makes enhancing lesions and blood vessels appear bright after gadolinium administration. However, dark blood imaging using T1-weighted Sampling Perfection with Application optimized Contrast using different flip angle Evolution (T1 SPACE) can be advantageous since it improves the conspicuity of small metastases and leptomeningeal disease. As a potential alternative to T1 SPACE, we evaluated a new dark blood sequence called echo-uT1 RESS (unbalanced T1 Relaxation-Enhanced Steady-State). PURPOSE: We compared the performance of echo-uT1 RESS with Dixon fid-uT1 RESS, MPRAGE, and T1 SPACE. STUDY TYPE: Retrospective, IRB approved. SUBJECTS/PHANTOM: Phantom to assess flow properties of echo-uT1 RESS. Twenty-one patients (14 female, age range 35-82 years) with primary and secondary brain tumors. FIELD STRENGTH/SEQUENCES: 3 Tesla/MPRAGE, T1 SPACE, Dixon fid-uT1 RESS, echo-uT1 RESS. ASSESSMENT: Flow phantom signal vs. velocity as a function of flip angle and sequence. Qualitative image assessment on 4-point scale. Quantitative evaluation of tumor-to-brain contrast, apparent contrast-to-noise ratio (aCNR), and vessel-to-brain aCNR. STATISTICAL TESTS: Friedman and Mann-Whitney U tests. A P value <0.05 was considered statistically significant. RESULTS: In the phantom, echo-uT1 RESS showed greater flow-dependent signal loss than fid-uT1 RESS. In patients, blood vessels appeared bright with MPRAGE, gray with fid-uT1 RESS, and dark with T1 SPACE and echo-uT1 RESS. For MPRAGE, Dixon fid-uT1 RESS, echo-uT1 RESS, and T1 SPACE, respective tumor-to-brain contrast values were 0.6 ± 0.3, 1.3 ± 0.5, 1.0 ± 0.4, and 0.6 ± 0.4, while normalized aCNR values were 68.9 ± 50.9, 128.4 ± 59.2, 74.2 ± 42.1, and 99.4 ± 73.9. DATA CONCLUSION: Volumetric dark blood contrast-enhanced brain MRI is feasible using echo-uT1 RESS. The dark blood effect was improved vs. fid-uT1 RESS, while both uT1 RESS versions provided better tumor-to-brain contrast than MPRAGE. Whereas T1 SPACE provided better tumor aSNR, echo-uT1 RESS provided better Weber contrast, lesion sharpness and a more consistent dark blood effect. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 1.

Improved Brain Tumor Conspicuity at 3 T Using Dark Blood, Fat-Suppressed, Dixon Unbalanced T1 Relaxation-Enhanced Steady-State MRI.

OBJECTIVES: Contrast-enhanced magnetic resonance imaging (MRI) is the cornerstone for brain tumor diagnosis and treatment planning. We have developed a novel dual-echo volumetric dark blood pulse sequence called Dixon unbalanced T1 relaxation-enhanced steady-state (uT 1 RESS) that improves the visibility of contrast-enhancing lesions while suppressing the tissue signals from blood vessels and fat. The purpose of this study was to test the hypothesis that Dixon uT 1 RESS would significantly improve the conspicuity of brain tumors compared with magnetization-prepared rapid gradient echo (MPRAGE), as well as to determine potential limitations of the technique. MATERIALS AND METHODS: This retrospective study was approved by the hospital institutional review board. Forty-seven adult patients undergoing an MRI scan for a brain tumor indication were included. Contrast-enhanced MRI of the brain was performed at 3 T using both MPRAGE and Dixon uT 1 RESS. To control for any impact of contrast agent washout during the scan procedure, Dixon uT 1 RESS was acquired in approximately half the subjects immediately after MPRAGE, and in the other half immediately before MPRAGE. Image quality, artifacts, and lesion detection were scored by 3 readers, whereas lesion apparent signal-to-noise ratio and lesion-to-background Weber contrast were calculated from region-of-interest measurements. RESULTS: Image quality was not rated significantly different between MPRAGE and Dixon uT 1 RESS, whereas motion artifacts were slightly worse with Dixon uT 1 RESS. Comparing Dixon uT 1 RESS with MPRAGE, the respective values for mean lesion apparent signal-to-noise ratio were not significantly different (199.31 ± 99.05 vs 203.81 ± 110.23). Compared with MPRAGE, Dixon uT 1 RESS significantly increased the tumor-to-brain contrast (1.60 ± 1.18 vs 0.61 ± 0.47 when Dixon uT1RESS was acquired before MPRAGE and 1.94 ± 0.97 vs 0.82 ± 0.55 when Dixon uT 1 RESS was acquired after MPRAGE). In patients with metastatic disease, Dixon uT 1 RESS detected at least 1 enhancing brain lesion that was missed by MPRAGE on average in 24.7% of patients, whereas Dixon uT 1 RESS did not miss any lesions that were demonstrated by MPRAGE. Dixon uT 1 RESS better detected vascular and dural invasion in a small number of patients. CONCLUSIONS: In conclusion, brain tumors were significantly more conspicuous at 3 T using Dixon uT 1 RESS compared with MPRAGE, with an approximately 2.5-fold improvement in lesion-to-background contrast irrespective of sequence order. It outperformed MPRAGE for the detection of brain metastases, dural or vascular involvement. These results suggest that Dixon uT 1 RESS could prove to be a useful adjunct or alternative to existing neuroimaging techniques for the postcontrast evaluation of intracranial tumors.

Epidemiology of male breast cancer.

BACKGROUND: Due to its rarity, few studies have characterized the epidemiology of male breast cancer. The purpose of this study was to determine survival and risk factors for male breast cancer in a large U.S. METHODS: In this study, 19,795 male patients with breast cancer were identified from the National Cancer Database (2004-2014). Patient demographics, tumor characteristics and treatments were analyzed by using descriptive statistics. We used multivariate Cox regression and Kaplan Meier analysis. RESULTS: Over 10 years, the incidence of male breast cancer increased from 7.2% to 10.3%, while mortality decreased from 11% to 3.8%. Socioeconomic factors predicting mortality included income medium, and high vs low (HR = 0.78; 0.68), private vs no insurance (HR = 0.73) and the academic research facility vs community cancer center (HR = 0.79). Significant predictors of all-cause mortality included age (HR = 1.04), tumor size (HR = 1.01), hormone receptor expression (HR = 0.8) and cancer stage I vs II, III, and IV at the time of diagnosis (HR = 1.5, 2.7, 4.4, 9.9 respectively). Other predictors of mortality include surgery (HR = 0.4), chemotherapy (HR = 0.8), radiation (HR = 0.8), and hormonal therapy (HR-0.8). CONCLUSIONS: Socioeconomic factors, cancer stage, tumor characteristics (size and grade), and high Charlson-Dayo score contributed to higher mortality among male patients diagnosed with breast cancer. Surgery was most effective, followed by radiation, chemotherapy, and hormonal therapy. Patients with positive ER or PR expression demonstrated better survival. Adjusting for socioeconomic factors, biomarker identification and timely, appropriately chosen treatment are likely to reduce the risk for mortality.

MGMT inhibition in ER positive breast cancer leads to CDC2, TOP2A, AURKB, CDC20, KIF20A, Cyclin A2, Cyclin B2, Cyclin D1, ERα and Survivin inhibition and enhances response to temozolomide.

The DNA damage repair enzyme, O6-methylguanine DNA methyltransferase (MGMT) is overexpressed in breast cancer, correlating directly with estrogen receptor (ER) expression and function. In ER negative breast cancer the MGMT promoter is frequently methylated. In ER positive breast cancer MGMT is upregulated and modulates ER function. Here, we evaluate MGMT's role in control of other clinically relevant targets involved in cell cycle regulation during breast cancer oncogenesis. We show that O6-benzylguanine (BG), an MGMT inhibitor decreases CDC2, CDC20, TOP2A, AURKB, KIF20A, cyclin B2, A2, D1, ERα and survivin and induces c-PARP and p21 and sensitizes ER positive breast cancer to temozolomide (TMZ). Further, siRNA inhibition of MGMT inhibits CDC2, TOP2A, AURKB, KIF20A, Cyclin B2, A2 and survivin and induces p21. Combination of BG+TMZ decreases CDC2, CDC20, TOP2A, AURKB, KIF20A, Cyclin A2, B2, D1, ERα and survivin. Temozolomide alone inhibits MGMT expression in a dose and time dependent manner and increases p21 and cytochrome c. Temozolomide inhibits transcription of TOP2A, AURKB, KIF20A and does not have any effect on CDC2 and CDC20 and induces p21. BG+/-TMZ inhibits breast cancer growth. In our orthotopic ER positive breast cancer xenografts, BG+/-TMZ decreases ki-67, CDC2, CDC20, TOP2A, AURKB and induces p21 expression. In the same model, BG+TMZ combination inhibits breast tumor growth in vivo compared to single agent (TMZ or BG) or control. Our results show that MGMT inhibition is relevant for inhibition of multiple downstream targets involved in tumorigenesis. We also show that MGMT inhibition increases ER positive breast cancer sensitivity to alkylator based chemotherapy.

Racial Disparity Among Women Diagnosed With Invasive Breast Cancer in a Large Integrated Health System.

PURPOSE: Reasons for the well-described disparity in outcomes between African American (AA) and non-Hispanic white (NHW) women with invasive breast cancer are unclear, making it difficult to identify solutions. This study examined the effects of demographics, biomarkers, tumor characteristics, cancer stage, morphology, and treatment variables on overall and cancer-free survival in these patient populations. METHODS: We retrospectively reviewed data for 6231 patients diagnosed with invasive breast cancer throughout an integrated health system from January 2006 through March 2015. Included for analysis were 5023 NHW and 413 AA women. All category and continuous variables in the study were described in the two groups using appropriate statistics. Kaplan-Meier method of survival with log-rank test was used to compare the two racial groups (NHW and AA). Cox proportional hazards regression was used to find hazard ratios for the predictors of survival and recurrence-free survival probability. Propensity probability match method (1:1) was used to match 319 NSW women to 319 similar AA women. Matching was done using all significant predictors, including demographic variables. RESULTS: Compared to NHW women, AA women presented with invasive breast cancer at a younger age (P<0.001) and had a higher proportion of stage IV cancers (P<0.001), which were more often infiltrating ductal carcinoma (P<0.003) and poorly differentiated (P<0.001). Within 10-year follow-up, AA women had shorter overall and recurrence-free survival (log-rank P<0.001), were 1.4 times more likely to die (P=0.009), and were twice as likely to have recurrence (P<0.001) than NHW women. In the matched groups, overall survival was similar for AA and NHW (log-rank P=0.0793); however, recurrence-free survival was higher in NHW than in AA women (P=0.047). CONCLUSIONS: When presenting characteristics of AA and NHW women with invasive breast cancer are matched, disparity in overall mortality and rate of recurrence appears to be reduced or perhaps eliminated, suggesting invasive breast cancers in AA and NHW women respond similarly to treatment. Further study is needed to explore the true effect of biological factors; however, rectifying delivery of and access to care might be expected to mitigate, in large part, the racial disparity currently seen in breast cancer outcomes.

New insights into estrogenic regulation of O6-methylguanine DNA-methyltransferase (MGMT) in human breast cancer cells: Co-degradation of ER-α and MGMT proteins by fulvestrant or O6-benzylguanine indicates fresh avenues for therapy.

Endocrine therapy using estrogen receptor-α (ER-α) antagonists for attenuating horm2one-driven cell proliferation is a major treatment modality for breast cancers. To exploit any DNA repair deficiencies associated with endocrine therapy, we investigated the functional and physical interactions of ER-α with O6-methylguanine DNA methyltransferase (MGMT), a unique DNA repair protein that confers tumor resistance to various anticancer alkylating agents. The ER-α -positive breast cancer cell lines (MCF-7, T47D) and ER- negative cell lines (MDAMB-468, MDAMB-231), and established inhibitors of ER-α and MGMT, namely, ICI-182,780 (Faslodex) and O6-benzylguanine, respectively, were used to study MGMT- ER interactions. The MGMT gene promoter was found to harbor one full and two half estrogen-responsive elements (EREs) and two antioxidant-responsive elements (AREs). MGMT expression was upregulated by estrogen, downregulated by tamoxifen in Western blot and promoter-linked reporter assays. Similarly, both transient and stable transfections of Nrf-2 (nuclear factor-erythroid 2-related factor-2) increased the levels of MGMT protein and activity 3 to 4-fold reflecting novel regulatory nodes for this drug-resistance determinant. Of the different ER-α antagonists tested, the pure anti-estrogen fulvestrant was most potent in inhibiting the MGMT activity in a dose, time and ER-α dependent manner, similar to O6-benzylguanine. Interestingly, fulvestrant exposure led to a degradation of both ER-α and MGMT proteins and O6-benzylguanine also induced a specific loss of ER-α and MGMT proteins in MCF-7 and T47D breast cancer cells with similar kinetics. Immunoprecipitation revealed a specific association of ER-α and MGMT proteins in breast cancer cells. Furthermore, silencing of MGMT gene expression triggered a decrease in the levels of both MGMT and ER-α proteins. The involvement of proteasome in the drug-induced degradation of both proteins was also demonstrated. Fulvestrant enhanced the cytotoxicity of MGMT-targeted alkylating agents, namely, temozolomide and BCNU by 3 to 4-fold in ER-α positive cells, but not in ER-negative cells. We conclude that MGMT and ER-α proteins exist as a complex and are co-targeted for ubiquitin-conjugation and subsequent proteasomal degradation. The findings offer a clear rationale for combining alkylating agents with endocrine therapy.

MGMT inhibition suppresses survivin expression in pancreatic cancer.

OBJECTIVES: Survivin, an antiapoptotic gene inhibited by p53, is overexpressed in human cancers and correlates with chemotherapy resistance. Here, we investigated the mutual regulatory mechanism between MGMT (O-methylguanine DNA methyltransferase) and survivin. METHODS: This study used standard techniques for protein and messenger RNA levels, promoter activity, protein-DNA interaction, cell viability, and correlative animal model. RESULTS: O-benzylguanine (BG), a potent inhibitor of MGMT (a DNA repair protein), curtails the expression of survivin in pancreatic cancer. Silencing MGMT by small interfering RNA down-regulates survivin transcription. p53 inhibition enhances MGMT and survivin expressions. When p53 was silenced, BG-induced MGMT inhibition was not associated with the down-regulation of survivin, underscoring the regulatory role of p53 in the MGMT-survivin axis. O-benzylguanine inhibits survivin and PCNA (proliferating cell nuclear antigen) at messenger RNA and protein levels in PANC-1 and L3.6pl cells and decreases survivin promoter activity via increased p53 recruitment to the survivin promoter. In orthotopic pancreatic xenografts established in nude mice, BG ± gemcitabine (GEM) decrease survivin expression in tumor tissue; protein levels and immunohistochemistry show significant decrease in survivin and PCNA levels, which correlate with increased sensitivity to GEM. CONCLUSIONS: MGMT inhibition is associated with decrease in survivin expression and increase in sensitivity to GEM in pancreatic cancer.

Disulfiram is a direct and potent inhibitor of human O6-methylguanine-DNA methyltransferase (MGMT) in brain tumor cells and mouse brain and markedly increases the alkylating DNA damage.

The alcohol aversion drug disulfiram (DSF) reacts and conjugates with the protein-bound nucleophilic cysteines and is known to elicit anticancer effects alone or improve the efficacy of many cancer drugs. We investigated the effects of DSF on human O(6)-methylguanine-DNA methyltransferase (MGMT), a DNA repair protein and chemotherapy target that removes the mutagenic O(6)-akyl groups from guanines, and thus confers resistance to alkylating agents in brain tumors. We used DSF, copper-chelated DSF or CuCl2-DSF combination and found that all treatments inhibited the MGMT activity in two brain tumor cell lines in a rapid and dose-dependent manner. The drug treatments resulted in the loss of MGMT protein from tumor cells through the ubiquitin-proteasome pathway. Evidence showed that Cys145, a reactive cysteine, critical for DNA repair was the sole site of DSF modification in the MGMT protein. DSF was a weaker inhibitor of MGMT, compared with the established O(6)-benzylguanine; nevertheless, the 24-36h suppression of MGMT activity in cell cultures vastly increased the alkylation-induced DNA interstrand cross-linking, G2/M cell cycle blockade, cytotoxicity and the levels of apoptotic markers. Normal mice treated with DSF showed significantly attenuated levels of MGMT activity and protein in the liver and brain tissues. In nude mice bearing T98 glioblastoma xenografts, there was a preferential inhibition of tumor MGMT. Our studies demonstrate a strong and direct inhibition of MGMT by DSF and support the repurposing of this brain penetrating drug for glioma therapy. The findings also imply an increased risk for alkylation damage in alcoholic patients taking DSF.

MGMT inhibition restores ERα functional sensitivity to antiestrogen therapy.

Antiestrogen therapy resistance remains a huge stumbling block in the treatment of breast cancer. We have found significant elevation of O(6) methylguanine DNA methyl transferase (MGMT) expression in a small sample of consecutive patients who have failed tamoxifen treatment. Here, we show that tamoxifen resistance is accompanied by upregulation of MGMT. Further we show that administration of the MGMT inhibitor, O(6)-benzylguanine (BG), at nontoxic doses, leads to restoration of a favorable estrogen receptor alpha (ERα) phosphorylation phenotype (high p-ERα Ser167/low p-ERα Ser118), which has been reported to correlate with sensitivity to endocrine therapy and improved survival. We also show BG to be a dual inhibitor of MGMT and ERα. In tamoxifen-resistant breast cancer cells, BG alone or in combination with antiestrogen (tamoxifen [TAM]/ICI 182,780 [fulvestrant, Faslodex]) therapy enhances p53 upregulated modulator of apoptosis (PUMA) expression, cytochrome C release and poly (ADP-ribose) polymerase (PARP) cleavage, all indicative of apoptosis. In addition, BG increases the expression of p21(cip1/waf1). We also show that BG, alone or in combination therapy, curtails the growth of tamoxifen-resistant breast cancer in vitro and in vivo. In tamoxifen-resistant MCF7 breast cancer xenografts, BG alone or in combination treatment causes significant delay in tumor growth. Immunohistochemistry confirms that BG increases p21(cip1/waf1) and p-ERα Ser167 expression and inhibits MGMT, ERα, p-ERα Ser118 and ki-67 expression. Collectively, our results suggest that MGMT inhibition leads to growth inhibition of tamoxifen-resistant breast cancer in vitro and in vivo and resensitizes tamoxifen-resistant breast cancer cells to antiestrogen therapy. These findings suggest that MGMT inhibition may provide a novel therapeutic strategy for overcoming antiestrogen resistance.

Recurrent inflammatory pseudotumor of the jaw with perineural intracranial invasion demonstrating sustained response to Rituximab.

Corticosteroids are the mainstay of treatment of inflammatory pseudotumor (IPT) of the head and neck; however, involvement of the skull base and mandible can be unresponsive to steroids and require surgical resection. IPT is known to usually contain a CD20+ lymphocyte subgroup. Rituximab, a chimeric anti-CD20 antibody, has been successfully utilized in the treatment of other CD20+ diseases, including the similar idiopathic orbital inflammatory disease. This is the first report to describe successful treatment with Rituximab of a recurrent IPT of the mandible with trigeminal spread and leptomeningeal involvement with clinical and radiologic evidence demonstrating a sustained response to therapy.

Combination of 6-thioguanine, capecitabine, and celecoxib with temozolomide or lomustine for recurrent high-grade glioma.

We evaluated the efficacy of temozolomide (TMZ) or lomustine (CCNU) in combination with 6-thioguanine, capecitabine, and celecoxib for the treatment of recurrent high-grade glioma. Forty-three patients with recurrent glioblastoma and 31 patients with recurrent anaplastic glioma (AG) were enrolled in this open-label, non-comparative study. Patients previously treated with TMZ received CCNU while all others received TMZ; all patients received 6-thioguanine, capecitabine, and celecoxib. Endpoints were 12-month progression-free survival (PFS) for patients with AG, 6-month PFS for patients with glioblastoma, duration of PFS, and MRI-based objective response rates. Results from the TMZ and CCNU treatment arms were combined in the final analysis because there was no statistically significant difference between them. Thirty-eight patients with glioblastoma were treated with the lomustine-based regimen, and five received the TMZ-based regimen. For the 43 glioblastoma patients, the objective response rate was 12 and 33% had stable disease; the 6-month PFS was 14% and median overall survival 32 weeks. For the 31 AG patients, the combined objective response rate was 26 and 42% had stable disease; the 12 month PFS was 44%. Treatment was reasonably well tolerated with hematological toxicity common and more frequent with CCNU than TMZ. The combination therapy with 6-thioguanine, capecitabine and celecoxib plus CCNU or TMZ does not appear to be more effective than other alkylating agent schedules for patients with recurrent glioblastoma. The combination, however, is promising for patients with recurrent high-grade AG.

Levetiracetam enhances p53-mediated MGMT inhibition and sensitizes glioblastoma cells to temozolomide.

Antiepileptic drugs (AEDs) are frequently used to treat seizures in glioma patients. AEDs may have an unrecognized impact in modulating O(6)-methylguanine-DNA methyltransferase (MGMT), a DNA repair protein that has an important role in tumor cell resistance to alkylating agents. We report that levetiracetam (LEV) is the most potent MGMT inhibitor among several AEDs with diverse MGMT regulatory actions. In vitro, when used at concentrations within the human therapeutic range for seizure prophylaxis, LEV decreases MGMT protein and mRNA expression levels. Chromatin immunoprecipitation analysis reveals that LEV enhances p53 binding on the MGMT promoter by recruiting the mSin3A/histone deacetylase 1 (HDAC1) corepressor complex. However, LEV does not exert any MGMT inhibitory activity when the expression of either p53, mSin3A, or HDAC1 is abrogated. LEV inhibits malignant glioma cell proliferation and increases glioma cell sensitivity to the monofunctional alkylating agent temozolomide. In 4 newly diagnosed patients who had 2 craniotomies 7-14 days apart, prior to the initiation of any tumor-specific treatment, samples obtained before and after LEV treatment showed the inhibition of MGMT expression. Our results suggest that the choice of AED in patients with malignant gliomas may have an unrecognized impact in clinical practice and research trial design.

Headache in Cerebral Venous Thrombosis: incidence, pattern and location in 200 consecutive patients.

We analyzed the incidence, pattern and location of headache in consecutive 200 patients with proven diagnosis of CVT to identify an association between localization of headache and site of sinus involvement. Headache was present in 136 (68%) patients. The duration of headache (reported in 128 patients) was reported as acute (1-3 days), 81 patients (60%); sub-acute (4-14 days), 33 patients (24%); and chronic (more than 14 days), 14 patients (10%). The quality of headache (reported in 72 patients) was reported as throbbing 12 (9%), band like 27 (20%), thunderclap 7 (5%), and other (pounding, exploding, stabbing, etc.) 26 (20%). The location of headache (reported in 101 patients) was reported as unilateral (one side of head) 48 (37%), localized (frontal, temporal, occipital, and neck) 25 (19%), and diffuse (whole head) 28 (20%). 43 (32%) patients had normal neurological examination (normal mental status, cranial nerves, motor and sensory examination with down going planters). 93 (68%) patients have abnormal findings on neurological examination including papilledema 29 (15%) patients, altered mental status 38 (19%), and focal neurological deficit 45 (22%) patients. There was no association between headache and presence of hemorrhage on CT and MRI (P = 0.1) or hydrocephalus (P = 0.09). There was no association between localization of headache and site of sinus thrombosis except sigmoid sinus thrombosis, where 17 out of 28 patients with involvement of sigmoid sinus alone or in combination with transverse sinus had pain in the occipital and neck region (P < 0.05). There was no association between lateralization of pain and site of thrombosis (P = 0.66).

Gene transfer of COX-1 improves lumen size and blood flow in carotid bypass grafts.

BACKGROUND: In autologous saphenous vein grafts, prostacyclin (PGI(1)), a vasoprotective molecule produced by normal endothelial cells, is down-regulated compared with ungrafted saphenous veins and normal carotid arteries. Reduced PGI(2) synthesis may contribute to local platelet deposition, vascular smooth muscle cell (VSMC) accumulation, atherosclerosis, and ultimately failure of venous bypass grafts. We have examined whether gene transfer-mediated overexpression of COX-1 in grafted veins (1) increases PGI(2) and cyclic AMP (cAMP) production, (2) leads to vasodilation and improved local blood flow in the presence of hypercholesterolemia, and (3) reduces neointima formation. MATERIALS AND METHODS: Jugular veins from New Zealand-White rabbits were incubated for 30 min ex vivo with 1 x 10(10) PFU/mL of an adenoviral vector encoding COX-1 (AdCOX-1; n = 10) or empty control (n = 10) and grafted to the carotid arteries. The rabbits were placed on a high-cholesterol diet for 4 w, and blood flow and histomorphometry of the grafts were assessed. RESULTS: In the AdCOX-1 group, blood flow was significantly increased (16.0 +/- 3.3 versus 12.5 +/- 3.3 mL/min; P < 0.05) compared with controls, and luminal area (8.9 +/- 1.4 versus 5.3 +/- 1.2 mm(2); P < 0.01) and outer circumference were larger. In six identically treated rabbits, graft PGI(2) and cAMP synthesis was increased at 72 h in AdCOX-1 compared with controls. CONCLUSION: Our data suggest a 30-min ex vivo exposure of vein grafts to AdCOX-1 increased local synthesis of PGI(2) and cAMP after graft surgery and resulted in better graft lumen and blood flow at 4 w.

Blockade of MGMT expression by O6 benzyl guanine leads to inhibition of pancreatic cancer growth and induction of apoptosis.

PURPOSE: We sought to determine whether administration of a MGMT blocker, O(6)-benzyl guanine (O(6)BG), at an optimal biological dose alone or in combination with gemcitabine inhibits human pancreatic cancer cell growth. EXPERIMENTAL DESIGN: Human pancreatic cancer L3.6pl and PANC1 cells were treated with O(6)BG, either alone or in combination with gemcitabine, and the therapeutic efficacy and biological activity of these drug combinations were investigated. RESULTS: O(6)BG sensitized pancreatic cancer cells to gemcitabine. Protein and mRNA expression of MGMT, cyclin B1, cyclin B2, cyclin A, and ki-67 were significantly decreased in the presence of O(6)BG. In sharp contrast, protein expression and mRNA message of p21(cip1) were significantly increased. Interestingly, O(6)BG increases p53-mediated p21(cip1) transcriptional activity and suppresses cyclin B1. In addition, our results indicate that p53 is recruited to p21 promoter. Furthermore, an increase in p21(cip1) and a decrease in cyclin transcription are p53 dependent. The volume of pancreatic tumors was reduced by 27% in mice treated with gemcitabine alone, by 47% in those treated with O(6)BG alone, and by 65% in those mice given combination. Immunohistochemical analysis showed that O(6)BG inhibited expression of MGMT and cyclins, and increased expression of p21(cip1). Furthermore, there was a significant decrease in tumor cell proliferation and an increase in tumor cell apoptosis. CONCLUSIONS: Collectively, our results show that decreased MGMT expression is correlated with p53 activation, and significantly reduced primary pancreatic tumor growth. These findings suggest that O(6)BG either alone or in combination with gemcitabine may provide a novel and effective approach for the treatment of human pancreatic cancer.

Cerebral venous thrombosis: analysis of a multicenter cohort from the United States.

OBJECTIVE: The data regarding diagnosis, prognosis, management, and outcome of patients with cerebral venous thrombosis are limited from the United States. METHODS: Patients with diagnosis of cerebral venous thrombosis were identified by International Classification of Diseases, Ninth Revision coding system at 10 centers in the United States during a 10-year period by retrospective chart review (1991-1997) or prospective enrollment (1997-2001). In all, 232 patients were screened for study inclusion and 182 of these patients were included in the study. RESULTS: The age range was 13 to 82 years (mean 38 years). Hypercoagulable state was the most common predisposing factor followed by pregnancy, malignancy, and homocystinemia. Neurologic examination revealed normal findings in 69 patients (38%); 37 (20%) were comatose, 59 (32%) had papilledema, and 71 (39%) had hemiparesis. In all, 61 patients (33%) had evidence of hemorrhage by computed tomography/magnetic resonance imaging. A total of 27 patients (15%) were treated with thrombolysis and 124 (68%) with anticoagulation. Overall mortality was 13% (n = 24). One-year follow up was available for 96 patients (53%). Of these, 26 (27%) were healthy, 43 (45%) were ambulatory with assistance, and 27 (28%) were still bedridden. On multivariate analysis, the best predictors of a poor outcome were coma at presentation (odds ratio 15.2 [95% confidence interval; 1.5-66]) and intracerebral hemorrhage (odds ratio 8.7 [95% confidence interval; 1.3-34.5]). CONCLUSION: Clinical and radiologic presentation of cerebral venous thrombosis in the United States is not much different from other parts of world but spectrum and frequency of predisposing factors are different. Number of patients treated with thrombolysis is higher as compared with other reported series of such patients. Coma at presentation and intracerebral hemorrhage were the strongest predictors of poor outcome, which is comparable with other series.

Local gene transduction of cyclooxygenase-1 increases blood flow in injured atherosclerotic rabbit arteries.

BACKGROUND: Cyclooxygenase-1 (COX-1) is the rate-limiting component in the synthesis of prostacyclin (PGI2), an important vasodilator and antithrombotic molecule. In balloon-injured, atherosclerosis-free porcine arteries, COX-1 gene transduction increases PGI2 production, induces durable vasodilation, and reduces thrombus formation. We tested the effectiveness of COX-1 local gene transduction for the prevention of postangioplasty restenosis in atherosclerotic arteries in a hypercholesterolemic rabbit model. METHODS AND RESULTS: We injured 1 carotid artery in 43 Watanabe heritable hyperlipidemic rabbits and performed local gene transduction using a viral vector containing the COX-1 gene (AdCOX-1, n=22) or no genes (Adnull, n=21). Three days later, AdCOX-1-treated arteries stimulated with arachidonic acid produced 100% more PGI2 (P<0.01), 400% more prostaglandin E2 (PGE2) (P<0.01), 400% more prostaglandin E1 (PGE1) (P<0.01), and 250% more cAMP (P<0.05) than Adnull-treated arteries. Twenty-eight days after treatment, Doppler sonography showed that blood flow velocity was preserved in AdCOX-1-treated arteries (ratio 0.92, injured compared with contralateral uninjured carotid artery) but reduced in Adnull-treated arteries (ratio 0.39), suggesting that AdCOX-1 prevented restenosis after injury. COX-1-transduced arteries also showed 80% greater lumen area 28 days after injury (P<0.01). CONCLUSIONS: The effectiveness of COX-1 in preventing restenosis and preserving normal blood flow 28 days after injury results from increased lumen area caused by durable vasodilation. COX-1 efficacy correlates with an early increase in the production of PGI2, PGE2, PGE1 (known to cause vasodilation), and cAMP. These results demonstrate for the first time that COX-1 gene transduction is an effective treatment for the prevention of postangioplasty restenosis of atherosclerotic arteries under clinically relevant conditions.

Brain metastasis from prostate carcinoma: The M. D. Anderson Cancer Center experience.

BACKGROUND: The objective of this study was to estimate the incidence and describe distribution, clinical presentation, and prognosis of brain metastases in patients with prostate carcinoma who were seen at The University of Texas M. D. Anderson Cancer Center (MDACC). METHODS: The authors reviewed the charts of 16,280 patients with prostate carcinoma in the MDACC patient data base. Of 131 patients with craniospinal metastases confirmed by neuroimaging (n=53 patients) or autopsy (n=78 patients), 103 of 16,280 patients (0.63%) had parenchymal metastases. RESULTS: The median patient age at diagnosis was 64 years (range, 16-85 years). The median interval from the diagnosis of prostate carcinoma to the detection of brain metastasis was 35 months for patients with adenocarcinoma and 48 months for patients with small cell carcinoma (SCC). Confusion, headache, and memory deficits were the most frequent initial symptoms. Eighty-six percent of patients had single lesions, and 14% of patients had > or = 2 lesions. Metastases were supratentorial in 81 of 103 patients (76%), infratentorial in 22 of 103 patients (21%), and both supratentorial and infratentorial in 3 of 103 patients (3%). SCC and cribriform subtypes were more likely than adenocarcinoma to metastasize to the brain (relative risk, 20.36; 95% confidence interval, 9.91-41.84). Regardless of histology, the median survival in untreated patients was 1 month compared with 3.5 months in patients who were treated with radiotherapy. Patients who underwent stereotactic radiosurgery (n=5 patients) had a longer median survival (9 months). Survival was not affected by supratentorial or infratentorial location of metastases. CONCLUSIONS: Brain metastasis from prostate carcinoma is a rare, terminal event with death in <1 year frequently due to advanced, systemic disease. The majority of metastases were single and supratentorial. The most common clinical presentation was nonfocal neurologic symptoms related to intracranial hypertension. A better understanding of the biology of prostate carcinoma will help clarify the basis for its metastasis to the brain.

Diffusion-weighted magnetic resonance imaging in superior sagittal sinus thrombosis.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) has shown high sensitivity in the diagnosis of acute arterial strokes. The pathophysiology of cerebral venous thrombosis with associated venous stroke appears to differ from that of arterial strokes. The purpose of this study was to describe DWI findings in venous strokes. METHODS: The authors reviewed 3 adults with superior sagittal sinus thrombosis who underwent DWI and magnetic resonance imaging within 24 hours of symptom onset. DWI was obtained at 1.5 T using the multishot echo planar technique (TR = 8000, TE = 97, field of view = 30 x 19 cm, slice thickness = 6.0 mm, interslice gap = 0.5 mm, matrix 128 x 128, NEX = 1). The diffusion gradients were applied in 3 orthogonal directions with 3 increasing b values (0-1000 s/mm2) to create average (trace) DWI images. Apparent diffusion coefficient (ADC) values were calculated on a pixel-by-pixel basis and displayed as ADC maps. RESULTS: DWI showed hyperintensities in patients 1 and 2 and hypointensity in patient 3 in corresponding to parenchymal lesions on conventional images. As compared to the homologous uninvolved location in the contralateral hemisphere, ADC values were decreased (0.53 x 10(-3) mm2/s [patient 1] and 0.68 x 10(-3) mm2/s [patient 2]) and increased (1.1 x 10(-3) mm2/s [patient 3]). The ADC ratio of the lesion in the involved to uninvolved side was 88% (patient 1), 81% (patient 2), and 120% (patient 3). CONCLUSION: Acute cerebral venous strokes may contain cytotoxic edema and/or vasogenic edema on DWI scans. DWI may be helpful in diagnosing cerebral venous thrombosis in cases with cryptic presentations.