Background and Purpose To correlate lesional iron deposition assessed by quantitative susceptibility mapping (QSM) with clinical and disease features in patients with cerebral cavernous malformations (CCM). Materials and Methods This study was approved by the local Institutional Review Boards, and informed consent was obtained from each participant. Patients underwent routine clinical scan in addition to QSM on 3 Tesla systems. Data from 105 patients met inclusion criteria. CCM lesions identified on susceptibility maps were cross-verified by T2 weighted images and differentiated based on prior overt hemorrhage. Mean susceptibility per CCM lesion (χ̄lesion) was measured to correlate with lesion volume, age at scan, and hemorrhagic history. Temporal rates of change in χ̄lesion was evaluated in 33 patients. Results Average χ̄lesion per patient was positively correlated with patient age at scan (p < 0.05, 4.1% change with each decade of life). CCM lesions with prior overt hemorrhages exhibited higher χ̄lesion than those without (p < 0.05). Changes in χ̄lesion during 3 – 15 months follow-up period were small in patients without new hemorrhage between the two scans [bias = −0.0003, 95% CI = [−0.06, 0.06]). Conclusion The study revealed a positive correlation between mean QSM signal and patient age in CCM lesions, higher mean QSM signal in hemorrhagic lesions, and minimum longitudinal QSM signal change in clinically stable lesions. QSM has the potential to be a novel imaging biomarker supplementing conventional imaging in CCM. The clinical significance of such measures merits further study.

The preparation and electrochemical characterization of glassy carbon electrodes (GCEs) modified with electropolymerized films of the cation N-(3-pyrrol-1-yl-propyl)-4,4'-bipyridine (PPB) are described. The behavior of a new biosensor, which exhibits a high catalytic activity for nitrite reduction and which consists of a maltose binding protein nitrite reductase fusion (MBP-Nir) immobilized on an electropolymerized film of PPB as an electrocatalyst, is also described. The insoluble perchlorate salt of the poly(benzyl viologen) dication was used to immobilize MBP-Nir onto an electrode previously modified with an electropolymerized film of PPB. The electropolymerized film of PPB on the GCE is redox active and exhibits special electron-transfer properties toward the MBP-Nir layer but not toward Nir (Nir without MBP fusion attached), suggesting an intimate interaction between the PPB film and the MBP-Nir layer. The kinetics of the catalytic reaction between the biosensor and nitrite anion were characterized using cyclic voltammetry and rotated disk electrode techniques, and a value of (4.6 +/- 0.5) x 10(3) M-1 S-1 was obtained for the rate constant.

The promoter of the constitutively expressed rice (Oryza sativa) actin 1 gene (Act1) is highly active in transformed rice plants (W. Zhang, D. McElroy, and R. Wu, Plant Cell 3:1150-1160, 1991). A region 834 bp upstream of the Act1 transcription initiation site contains all the regulatory elements necessary for maximal gene expression in transformed rice protoplasts (D. McElroy, W. Zhang, J. Cao, and R. Wu, Plant Cell 2:163-171, 1990). We have constructed a series of Act1 promoter deletions fused to a bacterial beta-glucuronidase reporter sequence (Gus). Transient expression assays in transformed rice protoplasts, as well as transformed maize cells and tissues, identified two distinct cis-acting regulatory elements in the Act1 promoter. A 38-bp poly(dA-dT) region was found to be a positive regulator of Act1 promoter activity. Deletion of the poly(dA-dT) element lowered Gus expression by at least threefold compared with expression produced by the full-length Act1 promoter. By gel retardation and footprinting, we identified a ubiquitous rice protein which specifically recognizes this poly(dA-dT) element in the constitutively active Act1 promoter. A CCCAA pentamer repeat-containing region was found to be a negative regulator of the Act1 promoter in transformed rice protoplasts. Transient expression assays in different maize cells and tissues with use of the Act1 deletion constructs suggested that the CCCAA pentamer repeat region functions in a complex tissue-specific manner. A CCCAA-binding protein was detected only in root extracts.

The promoter of the constitutively expressed rice (Oryza sativa) actin 1 gene (Act1) is highly active in transformed rice plants (W. Zhang, D. McElroy, and R. Wu, Plant Cell 3:1150-1160, 1991). A region 834 bp upstream of the Act1 transcription initiation site contains all the regulatory elements necessary for maximal gene expression in transformed rice protoplasts (D. McElroy, W. Zhang, J. Cao, and R. Wu, Plant Cell 2:163-171, 1990). We have constructed a series of Act1 promoter deletions fused to a bacterial beta-glucuronidase reporter sequence (Gus). Transient expression assays in transformed rice protoplasts, as well as transformed maize cells and tissues, identified two distinct cis-acting regulatory elements in the Act1 promoter. A 38-bp poly(dA-dT) region was found to be a positive regulator of Act1 promoter activity. Deletion of the poly(dA-dT) element lowered Gus expression by at least threefold compared with expression produced by the full-length Act1 promoter. By gel retardation and footprinting, we identified a ubiquitous rice protein which specifically recognizes this poly(dA-dT) element in the constitutively active Act1 promoter. A CCCAA pentamer repeat-containing region was found to be a negative regulator of the Act1 promoter in transformed rice protoplasts. Transient expression assays in different maize cells and tissues with use of the Act1 deletion constructs suggested that the CCCAA pentamer repeat region functions in a complex tissue-specific manner. A CCCAA-binding protein was detected only in root extracts.