Spinal cord involvement by atrophy and associations with disability are different between multiple sclerosis and neuromyelitis optica spectrum disorder.

BACKGROUND AND PURPOSE: The cervical and thoracic cross-sectional spinal cord area (CS-SCA) in multiple sclerosis (MS) correlates with disability, whilst such a correlation remains to be established in neuromyelitis optica spectrum disorder (NMOSD). Our aim was to clarify differences between MS and NMOSD in spinal cord segments where CS-SCA is associated with disability. METHODS: The CS-SCA at C2/C3, C3/C4, T8/T9 and T9/T10 vertebral disc levels was measured in 140 MS patients (111 with relapsing-remitting MS and 29 with progressive MS) and 42 NMOSD patients with anti-aquaporin-4 immunoglobulin G. Disability was evaluated by Expanded Disability Status Scale (EDSS) scores. Multivariate associations between CS-SCA and disability were assessed by stepwise forward multiple linear regression. RESULTS: Thoracic CS-SCA was significantly smaller in NMOSD patients than in MS patients even after adjusting for age, sex and disease duration (P = 0.002 at T8/T9), whilst there was no difference in cervical CS-SCA between the two diseases. Cervical and thoracic CS-SCA had a negative correlation with EDSS scores in MS patients (P < 0.0001 at C3/C4 and P = 0.0002 at T8/T9) whereas only thoracic CS-SCA correlated with EDSS scores in NMOSD patients (P = 0.0006 at T8/T9). By multiple regression analyses, predictive factors for disability in MS were smaller cervical CS-SCA, progressive course, older age and a higher number of relapses, whilst those in NMOSD were smaller thoracic CS-SCA and older age. CONCLUSIONS: Thoracic CS-SCA is a useful predictive marker for disability in patients with NMOSD whilst cervical CS-SCA is associated with disability in patients with MS.

Differences between primary central nervous system lymphoma and glioblastoma: topographic analysis using voxel-based morphometry.

AIM: To evaluate the diagnostic feasibility of probabilistic analysis using voxel-based morphometry (VBM) in differentiating primary central nervous system lymphoma (PCNSL) from glioblastoma (GBM). MATERIALS AND METHODS: In total, 118 patients with GBM (57 males, 61 females; mean [± standard deviation] age, 56.9±19.3 years; median, 61 years) and 52 patients with PCNSL (37 males, 15 females; mean age, 62±13.3 years, median, 66 years) were studied retrospectively. Each patient underwent preoperative contrast-enhanced T1-weighted imaging (CE-T1WI) using a 1.5 or 3 T magnetic resonance imaging (MRI) system. To assess preferential occurrence sites, images from CE-T1WI were co-registered and spatially normalised using the MNI152 T1 template. Subsequently, a region of interest (ROI) was placed in the centre of the enhancing tumour in normalised images with 1-mm isotropic resolution. The same ROI between normalised and T1 template images was set up using an ROI manager function in ImageJ software. A spherical volume of interest (VOI) with a radius of 10 mm was determined. A probability map was created by overlaying each image with the VOI. Each VOI was removed from T1 template images for VBM analysis. VBM analysis was performed using statistical parametric mapping (SPM) 12 software under default settings. RESULTS: VBM analysis showed significantly higher frequency in the splenium of the corpus callosum among PCNSL patients than among GBM patients (p<0.05; family-wise error correction). CONCLUSION: Topographic analysis using VBM provides useful information for differentiating PCNSL from GBM.

Artifact reduction in low and ultra-low dose chest computed tomography for patients with pacemaker: A phantom study.

INTRODUCTION: Implanted pacemakers (PM) would decrease the detection of lung nodules in chest computed tomography (CT) due to the metal artifact. This study aimed to explore the computer-aided diagnosis (CAD) detectability of pulmonary nodules for the patients implanted with PMs in low- and ultra-low-dose chest CT screening. METHODS: Four different sizes of artificial nodules were placed in an anthropomorphic chest phantom with two alternative diameters utilized. A commercially available PM was placed on the surface of the left chest wall of the phantom. The image acquisitions were performed with 120 kV and 150 kV with a dedicated selective photon shield made of tin filter (Sn150 kV) at low- and ultra-low- radiation doses (1.0 and 0.5 mGy of volume CT dose index), and reconstructed with and without Iterative Metal Artifact Reduction (iMAR, Siemens Healthineers, Erlangen, Germany). The relative artifact index (AIr) was calculated as an index of metal artifacts, and the nodule detectability was evaluated with a CAD system. RESULTS: Sn150 kV reduced AIr in all acquisitions when comparing 120 kV and Sn150 kV. Although PM reduced the detectability of nodules, Sn150 kV showed higher detectability compared to 120 kV. The use of iMAR showed inconsistent results in nodule detectability. CONCLUSION: Sn150 kV reduced PM-induced metal artifacts and improved nodule detectability with CAD compared to 120 kV acquisition in many conditions including low and ultra-low doses and large phantoms, but iMAR did not improve the detectability. IMPLICATIONS FOR PRACTICE: Based on the results of the current phantom study, low and ultra-low dose with Sn150 kV acquisition reduced PM-induced metal artifacts and improved nodule detectability.

Vessel-Selective 4D-MRA Using Superselective Pseudocontinuous Arterial Spin-Labeling with Keyhole and View-Sharing for Visualizing Intracranial Dural AVFs.

BACKGROUND AND PURPOSE: An accurate assessment of the hemodynamics of an intracranial dural AVF is necessary for treatment planning. We aimed to investigate the utility of 4D-MRA based on superselective pseudocontinuous arterial spin-labeling with CENTRA-keyhole and view-sharing (4D-S-PACK) for the vessel-selective visualization of intracranial dural AVFs. MATERIALS AND METHODS: We retrospectively analyzed the images of 21 patients (12 men and 9 women; mean age, 62.2 [SD,19.2] years) with intracranial dural AVFs, each of whom was imaged with DSA, 4D-S-PACK, and nonselective 4D-MRA based on pseudocontinuous arterial spin-labeling combined with CENTRA-keyhole and view-sharing (4D-PACK). The shunt location, venous drainage patterns, feeding artery identification, and Borden classification were evaluated by 2 observers using both MRA methods on separate occasions. Vessel selectivity was evaluated on 4D-S-PACK. RESULTS: Shunt locations were correctly evaluated in all 21 patients by both observers on both MRA methods. With 4D-S-PACK, observers 1 and 2 detected 76 (80.0%, P < .001) and 73 (76.8%, P < .001) feeding arteries of the 95 feeding arteries identified on DSA but only 39 (41.1%) and 46 (48.4%) feeding arteries with nonselective 4D-PACK, respectively. Both observers correctly identified 10 of the 11 patients with cortical venous reflux confirmed by DSA with both 4D-S-PACK and 4D-PACK (sensitivity = 90.9%, specificity = 90.9% for each method), and they made accurate Borden classifications in 20 of the 21 patients (95.2%) on both MRA methods. Of the 84 vessel territories examined, vessel selectivity was graded 3 or 4 in 73 (91.2%) and 66 (88.0%) territories by observers 1 and 2, respectively. CONCLUSIONS: 4D-S-PACK is useful for the identification of feeding arteries and accurate classifications of intracranial dural AVFs and can be a useful noninvasive clinical tool.

Intravoxel Incoherent Motion MR Imaging of Pediatric Intracranial Tumors: Correlation with Histology and Diagnostic Utility.

BACKGROUND AND PURPOSE: Intravoxel incoherent motion imaging, which simultaneously measures diffusion and perfusion parameters, is promising for brain tumor grading. However, intravoxel incoherent motion imaging has not been tested in children. The purpose of this study was to evaluate the correlation between intravoxel incoherent motion parameters and histology to assess the accuracy of intravoxel incoherent motion imaging for pediatric intracranial tumor grading. MATERIALS AND METHODS: Between April 2013 and September 2015, 17 children (11 boys, 6 girls; 2 months to 15 years of age) with intracranial tumors were included in this retrospective study. Intravoxel incoherent motion parameters were fitted using 13 b-values for a biexponential model. The perfusion-free diffusion coefficient, pseudodiffusion coefficient, and perfusion fraction were measured in high- and low-grade tumors. These intravoxel incoherent motion parameters and the ADC were compared using the unpaired t test. The correlations between the intravoxel incoherent motion parameters and microvessel density or the MIB-1 index were analyzed using the Spearman correlation test. Receiver operating characteristic analysis was used to evaluate diagnostic performance. RESULTS: The perfusion-free diffusion coefficient and ADC were lower in high-grade than in low-grade tumors (perfusion-free diffusion coefficient, 0.85 ± 0.40 versus 1.53 ± 0.21 × 10-3 mm2/s, P < .001; ADC, 1.04 ± 0.33 versus 1.60 ± 0.21 × 10-3 mm2/s, P < .001). The pseudodiffusion coefficient showed no difference between the groups. The perfusion fraction was higher in high-grade than in low-grade tumors (21.7 ± 8.2% versus 7.6 ± 4.3%, P < .001). Receiver operating characteristic analysis found that the combined perfusion-free diffusion coefficient and perfusion fraction had the best diagnostic performance for tumor differentiation (area under the curve = 0.986). CONCLUSIONS: Intravoxel incoherent motion imaging reflects tumor histology and may be a helpful, noninvasive method for pediatric intracranial tumor grading.

Predicting TERT promoter mutation using MR images in patients with wild-type IDH1 glioblastoma.

PURPOSE: The purpose of this study was to identify magnetic resonance imaging (MRI) features that are associated with telomerase reverse transcriptase promoter mutation (TERTm) in glioblastoma. MATERIALS AND METHODS: A total of 112 patients with glioblastoma who had MRI at 1.5- or 3.0-T were retrospectively included. There were 43 patients with glioblastoma with wild-type TERT (TERTw) (22 men, 21 women; mean age, 47±25 [SD] years; age range: 3-84 years) and 69 patients with glioblastoma with TERTm (34 men, 35 women; mean age 64±11 [SD] years; age range, 41--85 years). The feature vectors consist of 11 input units for two clinical parameters (age and gender) and nine MRI characteristics (tumor location, subventricular extension, cortical extension, multiplicity, enhancing volume, necrosis volume, the percentage of necrosis volume, minimum apparent diffusion coefficient [ADC] and normalized ADC). First, the diagnostic performance using univariate and multivariate logistic regression analyses was evaluated. Second, the cross-validation of the support vector machine (SVM) was performed by using leave-one-out method with 43 TERTw and 69 TERTm to evaluate the diagnostic performance. In addition, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for the differentiation between TERTw and TERTm were compared between logistic regression analysis and SVM. RESULTS: With multivariate analysis, the percentage of necrosis volume and age were significantly greater in TERTm glioblastoma than in TERTw glioblastoma. SVM allowed discriminating between TERTw glioblastoma and TERTm glioblastoma with sensitivity, specificity, PPV, NPV, and accuracy of 85.7% [60/70; 95% confidence interval (CI): 75.3-92.9%], 54.8% (23/42; 95% CI: 38.7-70.2%), 75.9% (60/79; 95% CI: 69.1-81.7%), 69.7% (23/33; 95% CI: 54.9-81.3%) and 74.1% (83/112; 95% CI: 65.0-81.9%), respectively. CONCLUSION: The percentage of necrosis volume and age may surrogate for predicting TERT mutation status in glioblastoma.

Diffusion-weighted magnetic resonance imaging of extraocular muscles in patients with Grave's ophthalmopathy using turbo field echo with diffusion-sensitized driven-equilibrium preparation.

PURPOSE: The purpose of this study was to correlate diffusivity of extraocular muscles, measured by three-dimensional turbo field echo (3DTFE) magnetic resonance (MR) imaging using diffusion-sensitized driven-equilibrium preparation, with their size and activity in patients with Grave's ophthalmopathy. MATERIALS AND METHODS: Twenty-three patients with Grave's ophthalmopathy were included. There were 17 women and 6 men with a mean age of 55.8±12.6 (SD) years (range: 26-83 years). 3DTFE with diffusion-sensitized driven-equilibrium MR images were obtained with b-values of 0 and 500s/mm2. The apparent diffusion coefficient (ADC) of extraocular muscles was measured on coronal reformatted MR images. Signal intensities of extraocular muscles on conventional MR images were compared to those of normal-appearing white matter, and cross-sectional areas of the muscles were also measured. The clinical activity score was also evaluated. Statistical analyses were performed with Pearson correlation and Mann-Whitney U tests. RESULTS: On 3DTFE with diffusion-sensitized driven-equilibrium preparation, the mean ADC of the extraocular muscles was 2.23±0.37 (SD)×10-3mm2/s (range: 1.70×10-3-3.11×10-3mm2/s). There was a statistically significant moderate correlation between ADC and the size of the muscles (r=0.61). There were no statistically significant correlations between ADC and signal intensity on conventional MR and the clinical activity score. CONCLUSION: 3DTFE with diffusion-sensitized driven-equilibrium preparation technique allows quantifying diffusivity of extraocular muscles in patients with Grave's ophthalmopathy. The diffusivity of the extraocular muscles on 3DTFE with diffusion-sensitized driven-equilibrium preparation MR images moderately correlates with their size.

A Qualitative and Quantitative Correlation Study of Lumbar Intervertebral Disc Degeneration Using Glycosaminoglycan Chemical Exchange Saturation Transfer, Pfirrmann Grade, and T1-ρ.

BACKGROUND AND PURPOSE: Glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging allows the direct measurement and mapping of glycosaminoglycans. In this study, we aimed to evaluate the usefulness of gagCEST imaging in the quantitative assessment of intervertebral disc degeneration in a comparison with Pfirrmann grade and T1-ρ measurements. MATERIALS AND METHODS: Ninety-six lumbar intervertebral discs in 24 volunteers (36.0 ± 8.5 years of age, 21 men and 3 women) were examined with both gagCEST imaging and T1-ρ measurements. The gagCEST imaging was performed at 3T with a saturation pulse with 1.0-second duration and the B1 amplitude of 0.8 µT followed by imaging by a 2D fast spin-echo sequence. The Z-spectra were obtained at 25 frequency offsets from -3 to +3 ppm (step, 0.25 ppm). A point-by-point B0 correction was performed with a B0 map. The gagCEST signal and T1-ρ values were measured in the nucleus pulposus in each intervertebral disc. The Pfirrmann grades were assessed on T2-weighted images. RESULTS: The gagCEST signal at grade I (5.36% ± 2.79%) was significantly higher than those at Pfirrmann grade II (3.15% ± 1.40%, P = .0006), grade III (0.14% ± 1.03%, P < .0001), grade IV (-1.75% ± 2.82%, P < .0001), and grade V (-1.47% ± 0.36%, P < .0001). The gagCEST signal at grade II was significantly higher than those of grade III (P < .0001), grade IV (P < .0001), and grade V (P < .0001). The gagCEST signal was significantly correlated negatively with Pfirrmann grade (P < .0001) and positively correlated with T1-ρ (P < .0001). CONCLUSIONS: GagCEST imaging could be a reliable and quantitative technique for assessing intervertebral disc degeneration.

Patients with osteoporosis on steroid medication tend to sustain subsequent fractures.

BACKGROUND AND PURPOSE: Repeat fractures after percutaneous vertebroplasty can be seen in patients with osteoporotic compression fractures. The purpose of this study was to identify characteristics of patients with new fractures after vertebroplasty. MATERIALS AND METHODS: Fifty-five consecutive patients were treated with vertebroplasty for painful osteoporotic compression fractures at our institution. The charts and radiographic studies of all patients were retrospectively reviewed. Special attention was paid to patient age and sex, imaging studies, long-term use of steroid medication, and treatment for osteoporosis. We used logistic regression analysis and the Fisher exact test for statistical evaluation. RESULTS: Thirty-five patients were treated with vertebroplasty at one time and did not develop new fractures, whereas 20 patients returned with new fractures. Sixteen of 55 patients had been on steroid medication. The incidence of subsequent vertebral compression fractures after vertebroplasty in patients on long-term steroid therapy was 69% (11/16), compared with 23% (9/39) in those with primary osteoporosis (ie, those who were not on steroid therapy). There was a statistically significant association between use of steroids and new fractures (P<.01). No statistically significant difference was noted in patient age, sex, and medication for osteoporosis. CONCLUSION: Patients who are on long-term steroid medication have an elevated risk of developing new fractures after vertebroplasty.

Vertebroplasty for osteoporotic fractures with spinal canal compromise.

BACKGROUND AND PURPOSE: Percutaneous vertebroplasty can aggravate spinal canal narrowing, especially in patients with preoperative retropulsion. The purpose of this study was to evaluate changes in spinal canal dimension during percutaneous vertebroplasty for osteoporotic fractures with retropulsion. MATERIALS AND METHODS: We reviewed all cases of osteoporotic vertebral fractures treated with vertebroplasty. Twenty-one patients (25 vertebrae) had a retropulsed fragment that compromised the dimension of the spinal canal on preoperative imaging. We measured the degree of retropulsion before and after vertebroplasty to evaluate changes in spinal canal dimension. We also evaluated pain, neurologic status, vertebral body height, and wedge angle. RESULTS: Mean retropulsion was 4.2 mm before and 4.4 mm after vertebroplasty. There was no statistically significant difference (P = .32). Mean increase in vertebral body height was 2.6 mm anteriorly, 1.7 mm centrally, and 0.3 mm posteriorly. Mean decrease in wedge angle was 4.7 degrees. There were statistically significant improvements in height and wedge angle (P < .01). None of our patients developed new symptoms during vertebroplasty or thereafter. Twenty of 21 patients (95%) showed partial or complete immediate pain relief, whereas 1 patient did not improve. CONCLUSION: Vertebroplasty can be performed safely in patients with spinal canal compromise. This procedure can reduce pain, increase vertebral body height, and decrease wedge angle without worsening of retropulsion.

MR Imaging-Based Analysis of Glioblastoma Multiforme: Estimation of IDH1 Mutation Status.

BACKGROUND AND PURPOSE: Glioblastoma multiforme is highly aggressive and the most common type of primary malignant brain tumor in adults. Imaging biomarkers may provide prognostic information for patients with this condition. Patients with glioma with isocitrate dehydrogenase 1 (IDH1) mutations have a better clinical outcome than those without such mutations. Our purpose was to investigate whether the IDH1 mutation status in glioblastoma multiforme can be predicted by using MR imaging. MATERIALS AND METHODS: We retrospectively studied 55 patients with glioblastoma multiforme with wild type IDH1 and 11 patients with mutant IDH1. Absolute tumor blood flow and relative tumor blood flow within the enhancing portion of each tumor were measured by using arterial spin-labeling data. In addition, the maximum necrosis area, the percentage of cross-sectional necrosis area inside the enhancing lesions, and the minimum and mean apparent diffusion coefficients were obtained from contrast-enhanced T1-weighted images and diffusion-weighted imaging data. Each of the 6 parameters was compared between patients with wild type IDH1 and mutant IDH1 by using the Mann-Whitney U test. The performance in discriminating between the 2 entities was evaluated by using receiver operating characteristic analysis. RESULTS: Absolute tumor blood flow, relative tumor blood flow, necrosis area, and percentage of cross-sectional necrosis area inside the enhancing lesion were significantly higher in patients with wild type IDH1 than in those with mutant IDH1 (P < .05 each). In contrast, no significant difference was found in the ADC(minimum) and ADC(mean). The area under the curve for absolute tumor blood flow, relative tumor blood flow, percentage of cross-sectional necrosis area inside the enhancing lesion, and necrosis area were 0.850, 0.873, 0.739, and 0.772, respectively. CONCLUSIONS: Tumor blood flow and necrosis area calculated from MR imaging are useful for predicting the IDH1 mutation status.

MR Imaging Findings of a Leiomyosarcoma of the Thoracic Spine: A Case Report.

We report a case of leiomyosarcoma of the thoracic spine. Primary leiomyosarcoma is a malignant connective tissue tumor originating from smooth muscle cells. Leiomyosarcoma frequently occurs in the uterus, retroperitoneal space, gastrointestinal tract, and deep soft tissues; primary leiomyosarcoma of the bone is rare. The MR imaging including intravoxel incoherent motion (IVIM) imaging findings of the current case indicated a low diffusion coefficient and high blood flow, which were in concurrence with high cell density on histology and increased vascularity by angiography. Although some benign tumors such as osteoblastoma and giant cell tumor would show similar findings on IVIM imaging, these additional imaging features may narrow the differential diagnosis of spinal tumors.

Physicochemical properties of reduced nicotinamide adenine dinucleotide phosphate-cytochrome P-450 reductase from bovine adrenocortical microsomes.

Adrenocortical NADPH-cytochrome P-450 reductase (EC. 1.6.2.4) was purified from bovine adrenocortical microsomes by detergent solubilization and affinity chromatography. The purified cytochrome P-450 reductase was a single protein band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, being electrophoretically homogeneous and pure. The cytochrome P-450 reductase was optically a typical flavoprotein. The absorption peaks were at 274, 380 and 45 nm with shoulders at 290, 360 and 480 nm. The NADPH-cytochrome P-450 reductase was capable of reconstituting the 21-hydroxylase activity of 17 alpha-hydroxyprogesterone in the presence of cytochrome P-45021 of adrenocortical microsomes. The specific activity of the 21-hydroxylase of 17 alpha-hydroxyprogesterone in the reconstituted system using the excess concentration of the cytochrome P-450 reductase, was 15.8 nmol/min per nmol of cytochrome P-45021 at 37 degrees C. The NADPH-cytochrome P-450 reductase, like hepatic microsomal NADPH-cytochrome P-450 reductase, could directly reduce the cytochrome P-45021. The physicochemical properties of the NADPH-cytochrome P-450 reductase were investigated. Its molecular weight was estimated to be 80 000 +/- 1000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and analytical ultracentrifugation. The cytochrome P-450 reductase contained 1 mol each FAD and FMN as coenzymes. Iron, manganese, molybdenum and copper were not detected. The Km values of NADPH and NADH for the NADPH-cytochrome c reductase activity and those of cytochrome c for the activity of NADPH-cytochrome P-450 reductase were determined kinetically. They were 5.3 microM for NADPH, 1.1 mM for NADH, and 9-24 microM for cytochrome c. Chemical modification of the amino acid residues showed that a histidyl and cysteinyl residue are essential for the binding site of NADPH of NADPH-cytochrome P-450 reductase.

The role of the sugar regions of components of the cytochrome P-450-linked mixed-function oxidase (monooxygenase) system of bovine adrenocortical mitochondria.

Cytochrome P-450scc from bovine adrenocortical mitochondria was found to be a glycoprotein, similar to NADPH-adrenodoxin reductase. The role of sugar moieties of components of the cytochrome P-450-linked mixed-function oxidase system was investigated. The NADPH-ferricyanide reductase activity of NADPH-adrenodoxin reductase was not affected by neuraminidase treatment, but NADPH-cytochrome c reductase activity of NADPH-adrenodoxin reductase and adrenodoxin was lost. Cytochrome P-450scc treated with neuraminidase could not be reduced by NADPH-adrenodoxin reductase and adrenodoxin, and the side-chain cleavage activity of cholesterol by the cytochrome P-450-linked mixed-function oxidase system was lost by neuraminidase treatment of cytochrome P-450scc or NADPH-adrenodoxin reductase or both. These results indicate that the sugar moieties of the components of the cytochrome P-450-linked mixed-function oxidase system are necessary for binding and attaching of the components and electron transport.

Purification and reconstitution of the steroid 21-hydroxylase system (cytochrome P-450-linked mixed function oxidase system) of bovine adrenocortical microsomes.

The steroid 21-hydroxylase system was purified from bovine adrenocortical microsomes. The physicochemical properties of NADPH-cytochrome P-450s21 were studied. The properties of NADPH-cytochrome P-450 reductase (EC 1.6.2.4) of bovine adrenocortical microsomes have been reported previously (Hiwatashi, A. and Ichikawa, Y. (1979) Biochim. Biophys. Acta 580, 44-63). The steroid 21-hydroxylase system was reconstituted by cytochrome P-450s21 and NADPH-cytochrome P-450 reductase in the presence of detergent. The substrate specificity of the cytochrome P-450s21 was examined with the reconstituted system. The enzyme system was active in the 21-hydroxylations of 17 alpha-hydroxyprogesterone and progesterone, and the N-demethylation of (+)-benzphetamine. The cytochrome P-450s21 purified to as high as 16-17 nmol per mg protein was an electrophoretically pure glycoprotein. The molecular weight of the cytochrome P-450s21 was estimated to be 47 500 by SDS-polyacrylamide gel electrophoresis. Although cytochrome P-450scc or cytochrome P-45011 beta of bovine adrenocortical mitochondria did not react with antibody to cytochrome P-450BPA of bovine liver microsomes, the cytochrome P-450s21 formed an immunoprecipitin line against the antibody to cytochrome P-450BPA in the Ouchterlony double diffusion test.

Effects of cyanide on stearyl-coenzyme A desaturase activities in microsomes from various mammalian tissues.

The effect of potassium cyanide on the desaturase activity for stearyl-CoA in microsomes of various mammalian tissues has been investigated. Potassium cyanide inhibited the desaturase activities in microsomes from livers of rat, hen, guinea pig and rat lung, but not the activities in microsomes from rabbit liver, pig thyroid and bovine adrenocortex, It is concluded that the so-called "cyanide-sensitive factor" does not seem to be common to all the desaturase activities of stearyl-CoA in the microsomes of mammalian tissues.

Existence of multiple forms of cytochrome P-450scc purified from bovine adrenocortical mitochondria.

Three fractions of cytochrome P-450scc (denoted as fractions a, b, and c) were purified by a new procedure from bovine adrenocortical mitochondria. The amino-acid content analyses of these three fractions showed no difference. NH2-terminal amino-acid sequences of cytochrome P-450scc fractions, a and b agreed completely with the sequence deduced by nucleotide sequence of cDNA of cytochrome P-450scc mRNA (Morohashi, K., Fujii-Kuriyama, Y., Okada, Y., Sogawa, K., Hirose, T., Inayama, S. and Omura, T. (1984) Proc. Natl. Acad. Sci. USA 81, 4647-4651), whereas the sequence of fraction c showed a missing of isoleucine at the NH2-terminal. COOH-terminal ámino-acid sequences of fractions a, b and c were -Gln-Ala-COOH, identical with the deduced sequence from the cDNA. Measurements of the enzymatic activities of cholesterol side-chain cleavage reaction revealed no distinct difference among these three fractions. Although each of these fractions appeared as a single protein staining band upon SDS-polyacrylamide gel electrophoresis, these fractions showed heterogeneities upon two-dimensional electrophoresis and chromatofocusing. Fraction a contained the major form of cytochrome P-450scc, and its isoelectric point was estimated to be pH 7.8 by isoelectric focusing under both native and denatured conditions, and this value was confirmed by chromatofocusing. Neither of the carbohydrate-specific stainings (such as periodic acid-Schiff staining and lectin-peroxidase stainings using concanavalin A, wheat-germ agglutinin, and soybean agglutinin) of purified cytochrome P-450scc fractions after the electrophoretic resolution on SDS-polyacrylamide gel could show cytochrome P-450scc fractions as glycoproteins, suggesting that the heterogeneities were not due to the glycosylation state.

Localization of cytochrome P-450-linked mixed function oxidase and steroid hydroxylations within zones of bovine adrenocortices.

The localization of contents and activities of components of cytochrome P-450-linked mixed function oxidase system and the hydroxylation of steroids in mitochondria and microsomes within zones of adrenocortices was investigated. NADPH-adrenodoxin reductase activity was higher in the zona glomerulosa than in the other zones. Adrenodoxin content was present at high concentration in the zona fasciculata. The localization of cytochrome P-450 within zones of adrenocortices has already been reported (Ichikawa, Y., Kuroda, M. and Yamano, T. (1970) J. Cell Biol 45, 640--653). The zona fasciculata contained more mitochondrial and microsomal cytochromes P-450 than the zona glomerulosa or zona reticularis. Cleavage activity of the side chain of cholesterol was found in three zones. However, particularly high activity was observed in the zona fasciculata and zona reticularis. 11beta-Hydroxylation was found in the zona glomerulosa. 21-Hydroxylation activity was especially higher in the zona fasciculata than in the other zones.

Structural properties and RNA-binding activities of two RNA recognition motifs of a mouse neural RNA-binding protein, mouse-Musashi-1.

mouse-Musashi-1 (m-Msi-1) is an RNA-binding protein, abundantly expressed in the developing mammalian central nervous system (CNS). m-Msi-1 contains two RNA recognition motifs (RRMs). In this study, we found that the N-terminal RRM of m-Msi-1 (MMA) binds strongly to poly(G) and weakly to poly(U) in a way similar to that of the full-length m-Msi-1 protein characterized previously. The C-terminal RRM of m-Msi-1 (MMB), however, does not bind to RNA. In addition, the circular dichroism (CD) spectra of the two RRMs showed that the alpha-helical content of MMA is significantly higher than that of MMB, indicating that some differences in the secondary structure may be responsible for the distinct RNA binding properties of MMA and MMB.

Organ-specific properties of cytochromes P-450s21 (steroid 21-hydroxylases) of liver and adrenocortical microsomes.

Organ specificities of cytochrome P-450s21 (steroid 21-hydroxylase) were investigated. The substrate specificity of the liver cytochrome P-450s21 was found to be different from that of adrenocortical cytochrome P-450s21. The steroid 21-hydroxylase activity of liver microsomes decreased with treatment by sodium phenobarbital or beta-naphthoflavone and was inhibited by anti-cytochrome b5 immunoglobulin, although that of adrenocortical microsomes was not. The liver cytochrome P-450s21 was immunochemically similar to adrenocortical cytochrome P-450s21. The bovine liver and adrenocortical cytochromes P-450s21 showed immunoprecipitin lines against antibody to bovine adrenocortical cytochrome P-450s21. The molecular masses of the bovine liver and adrenocortical cytochromes P-450s21 were 60 +/- 1 and 50 +/- 1 kDa, respectively. The content of cytochrome P-450s21 and its percentage for the total microsomal cytochrome P-450 were immunochemically determined using the antibody to the bovine adrenocortical cytochrome P-450s21.