Reduction of respiratory motion artifacts in gadoxetate-enhanced MR with a deep learning-based filter using convolutional neural network.

OBJECTIVES: To reveal the utility of motion artifact reduction with convolutional neural network (MARC) in gadoxetate disodium-enhanced multi-arterial phase MRI of the liver. METHODS: This retrospective study included 192 patients (131 men, 68.7 ± 10.3 years) receiving gadoxetate disodium-enhanced liver MRI in 2017. Datasets were submitted to a newly developed filter (MARC), consisting of 7 convolutional layers, and trained on 14,190 cropped images generated from abdominal MR images. Motion artifact for training was simulated by adding periodic k-space domain noise to the images. Original and filtered images of pre-contrast and 6 arterial phases (7 image sets per patient resulting in 1344 sets in total) were evaluated regarding motion artifacts on a 4-point scale. Lesion conspicuity in original and filtered images was ranked by side-by-side comparison. RESULTS: Of the 1344 original image sets, motion artifact score was 2 in 597, 3 in 165, and 4 in 54 sets. MARC significantly improved image quality over all phases showing an average motion artifact score of 1.97 ± 0.72 compared to 2.53 ± 0.71 in original MR images (p < 0.001). MARC improved motion scores from 2 to 1 in 177/596 (29.65%), from 3 to 2 in 119/165 (72.12%), and from 4 to 3 in 34/54 sets (62.96%). Lesion conspicuity was significantly improved (p < 0.001) without removing anatomical details. CONCLUSIONS: Motion artifacts and lesion conspicuity of gadoxetate disodium-enhanced arterial phase liver MRI were significantly improved by the MARC filter, especially in cases with substantial artifacts. This method can be of high clinical value in subjects with failing breath-hold in the scan. KEY POINTS: • This study presents a newly developed deep learning-based filter for artifact reduction using convolutional neural network (motion artifact reduction with convolutional neural network, MARC). • MARC significantly improved MR image quality after gadoxetate disodium administration by reducing motion artifacts, especially in cases with severely degraded images. • Postprocessing with MARC led to better lesion conspicuity without removing anatomical details.

Relative frequency, clinical, neuroimaging, and postsurgical features of pediatric temporal lobe epilepsy.

We describe the relative frequency, clinical features, neuroimaging and pathological results, and outcome after pharmacological or surgical intervention for a series of pediatric patients with temporal lobe epilepsy (TLE) from an epilepsy center in Brazil. The medical records of children younger than 12 years with features strongly suggestive of TLE were reviewed from January 1999 to June 1999. Selected children were evaluated regarding clinical, EEG, and magnetic resonance imaging (MRI) investigation and divided into three groups according to MRI: group 1 (G1, N = 9), patients with hippocampal atrophy; group 2 (G2, N = 10), patients with normal MRI, and group 3 (G3, N = 12), patients with other specific temporal lesions. A review of 1732 records of children with epilepsy revealed 31 cases with TLE (relative frequency of 1.79%). However, when the investigation was narrowed to cases with intractable seizures that needed video-EEG monitoring (N = 68) or epilepsy surgery (N = 32), the relative frequency of TLE increased to 19.11 (13/68) and 31.25% (10/32), respectively. At the beginning of the study, 25 of 31 patients had a high seizure frequency (80.6%), which declined to 11 of 31 (35.5%) at the conclusion of the study, as a consequence of pharmacological and/or surgical therapy. This improvement in seizure control was significant in G1 (P < 0.05) and G3 (P < 0.01) mainly due to good postsurgical outcome, and was not significant in G2 (P > 0.1, McNemar's test). These results indicate that the relative frequency of TLE in children was low, but increased considerably among cases with pharmacoresistant seizures. Patients with specific lesions were likely to undergo surgery, with good postoperative outcomes.

Expression and functional analysis of an N-truncated NifA protein of Herbaspirillum seropedicae.

In Herbaspirillum seropedicae, an endophytic diazotroph, nif gene expression is under the control of the transcriptional activator NifA. We have over-expressed and purified a protein containing the central and C-terminal domains of the H. seropedicae NifA protein, N-truncated NifA, fused to a His-Tag sequence. This fusion protein was found to be partially soluble and was purified by affinity chromatography. Band shift and footprinting assays showed that the N-truncated NifA protein was able to bind specifically to the H. seropedicae nifB promoter region. In vivo analysis showed that this protein activated the nifH promoter of Klebsiella pneumoniae in Escherichia coli only in the absence of oxygen and this activation was not negatively controlled by ammonium ions.

Regulation of Azospirillum brasilense nifA gene expression by ammonium and oxygen.

The structure and activity of the nifA promoter of Azospirillum brasilense was studied using deletion analysis. An essential region for nifA promoter activity was identified between nucleotides -67 and -47 from the identified transcription start site. A sequence resembling a sigma(70) recognition site occurs in this region and may constitute the nifA gene promoter. The regulation of the nifA gene was studied in plasmid and chromosomal nifA::lacZ fusions. Full expression was obtained under low oxygen levels and in the absence of ammonium ions. Repression of nifA expression involves a synergistic effect between oxygen and ammonium.

Novel antibiotics, furaquinocins C, D, E, F, G and H.

Furaquinocins C, D, E, F, G and H, congeners of furaquinocins A and B, were isolated from the culture broth of Streptomyces sp. KO-3988 and their structures have been determined on the basis of their spectroscopical and chemical properties. These antibiotics showed cytocidal activities against HeLa S3 and B16 melanoma cells in vitro.

A novel antibiotic, sohbumycin. Taxonomy, fermentation, isolation and physico-chemical and biological characteristics.

A new antibiotic sohbumycin, was isolated from the culture broth of Streptomyces sp. No. 82-85. It appeared to belong to the peptide lactone type of antibiotics from physico-chemical studies and has an empirical formula of C31H47N8O10Cl. In in vitro studies, the antibiotic was found to possess potent cytocidal activity against HeLa S3 cells and antimicrobial activities against Gram-positive bacteria with MIC values about 0.3-0.6 microgram/ml, but showed no activity on the Gram-negative bacteria, yeast and fungi tested.

Structures of trienomycins A, B and C, novel cytocidal ansamycin antibiotics.

The structures of novel antibiotics, trienomycins A, B and C produced by Streptomyces sp. No. 83-16, have been determined on the basis of their spectroscopical and chemical properties. Trienomycins are unique ansamycin antibiotics with a triene and an 1,3,5-trisubstituted benzene moieties in the molecule. The antibiotics possess potent cytocidal activity against HeLa S3 cells at concentrations of 0.005 (trienomycin A), 0.1 (trienomycin C) and 0.2 micrograms/ml (trienomycin B) (IC50 value), respectively. However, trienomycins showed no antimicrobial activity against the bacteria, fungi and yeasts examined with the exception of weak activity versus Piricularia oryzae at a concentration of 1,000 micrograms/ml.

Structural study of isoflavonoids possessing antioxidant activity isolated from the fermentation broth of Streptomyces sp.

Structures of three antioxidant isoflavonoids isolated from the cultured broth of Streptomyces sp. OH-1049 were shown to be 4',7,8-trihydroxyisoflavone (1), 3',4',7-trihydroxyisoflavone (2) and 8-chloro-3',4',5,7-tetrahydroxyisoflavone (3), respectively. Among them, 3 is a novel isoflavonoid possessing a chlorine atom in the molecule. Compound 1 was synthesized and its antitumor activities were tested against IMC carcinoma, S180, P388 leukemia and P388/ADM leukemia in vivo. As a result, 1 showed 139% increase in life span (ILS) against S180 bearing mice whereas it showed slight or no ILS against IMC carcinoma, P388 leukemia and P388/ADM leukemia bearing mice.

Structural study of a new antitumor antibiotic, kazusamycin.

The structure of a new antitumor antibiotic, kazusamycin produced by Streptomyces sp. No. 81-484, was determined on the basis of its spectral and chemical properties. Kazusamycin has a structure characteristic of an unsaturated, branched-chain fatty acid with a terminal delta-lactone ring.

Novel antibiotics, furaquinocins A and B. Taxonomy, fermentation, isolation and physico-chemical and biological characteristics.

Two novel antibiotics, furaquinocins A and B were isolated from the culture broth of Streptomyces sp. KO-3988. These antibiotics possess cytocidal activities against HeLa S3 cells in vitro at concentrations of 3.1 micrograms/ml for A and 1.6 micrograms/ml for B. Neither substance possessed antimicrobial activities against Gram-positive and Gram-negative bacteria, fungi or yeast at a concentration of 1,000 micrograms/ml.

Studies on a novel antitumor antibiotic, phenazinomycin: taxonomy, fermentation, isolation, and physicochemical and biological characteristics.

A new antibiotic, phenazinomycin (C27H32N2O, MW 400), was isolated from the cultural mycelium of Streptomyces sp. WK-2057. This antibiotic possesses antibacterial activities against Gram-positive bacteria in vitro, direct cytotoxic activities against HeLa S3, P388 and P388 doxorubicin-resistant cells in vitro and antitumor activities against experimental murine tumors in vivo.

Novel cytocidal antibiotics, glucopiericidinols A1 and A2. Taxonomy, fermentation, isolation, structure elucidation and biological characteristics.

Two novel antibiotics, glucopiericidinols A1 (1) and A2 (2) were isolated from the cultured broth of Streptomyces sp. OM-5689. The structures of these two compounds were deduced employing spectroscopic analyses. These antibiotics showed potent cytocidal activities against HeLa S3 cells in vitro (MIC 1: 0.39 microgram/ml, 2: 0.10 microgram/ml) when the cells were exposed to the antibiotics for 3 days. Although 1 and 2 showed no activity at 1,000 micrograms/ml against various Gram-positive and Gram-negative bacteria, yeast or fungi, they did have inhibitory activity against Piricularia oryzae (MIC of 1: 125 micrograms/ml, of 2: 31 micrograms/ml).

Antitumor activity of trienomycin A on murine tumors.

The antitumor activity of a novel ansamycin antibiotic, trienomycin A, against various murine tumors was studied with two treatment schedules. The intraperitoneal injection of the antibiotic showed remarkable antitumor activity on sarcoma 180 and P388 leukemia at doses of 160 or 320 mg/kg, showing 151% and 100% increase in life span, respectively. Trienomycin A inhibited the growth of Ehrlich and Meth A cells in vitro at doses of 0.1-0.4 microgram/ml when the cells were exposed to the antibiotic for 72 hours. The incorporation of [3H]thymidine into acid precipitable material in HeLa cells was slightly more marked than that of [3H]uridine and [3H]leucine when the cells were exposed to 0.04 or 0.08 microgram/ml of trienomycin A for 4 hours. It appeared that trienomycin A showed antitumor activity by direct cytotoxic action.

Isolation of isoflavonoids possessing antioxidant activity from the fermentation broth of Streptomyces sp.

Three antioxidant isoflavonoids characterized as 4',7,8-trihydroxyisoflavone (1), 3',4',7-trihydroxyisoflavone (2) and 8-chloro-3',4',5,7-tetrahydroxyisoflavone (3) were isolated from the cultured broth of Streptomyces sp. OH-1049. Among them, 3 is a novel isoflavonoid possessing a chlorine atom in the molecule. In in vitro studies, these antibiotics were found to possess antioxidant activity whereas showed almost no cytocidal activities against HeLa S3 cells.

A new antibiotic, okicenone. I. Taxonomy, fermentation, isolation and biological characteristics.

A new antibiotic, okicenone was isolated from the culture broth of Streptomyces sp. KO-3599. The antibiotic possesses cytocidal activity against mammalian tumor cells in vitro at concentrations of 0.53-11.0 micrograms/ml whereas the antibiotic showed no antimicrobial activities against Gram-positive and Gram-negative bacteria, fungi or yeast at a concentration of 1,000 micrograms/ml.

Adxanthromycins A and B, new inhibitors of ICAM-1/LFA-1 mediated cell adhesion molecule from Streptomyces sp. NA-148. II. Physico-chemical properties and structure elucidation.

Adxanthromycins A and B are new inhibitors of ICAM-1/LFA-1 mediated cell adhesion molecule isolated from the fermentation broth of Streptomyces sp. NA-148. The molecular formula of adxanthromycins A and B were determined as C42H40O17 and C48H50O22, respectively by FAB-MS and NMR spectral analyses, and the structures of both compounds were elucidated to be a dimeric anthrone peroxide skeleton containing alpha-D-galactose by various NMR spectral analyses and chemical degradation.

Studies on a novel cytocidal antibiotic, trienomycin A. Taxonomy, fermentation, isolation, and physico-chemical and biological characteristics.

A new antibiotic, trienomycin A, has been isolated from the culture broth of Streptomyces sp. No. 83-16. The physico-chemical characteristics of the antibiotic suggested that it belongs to the group of ansamycin antibiotics with a triene moiety in the molecule. The molecular formula of trienomycin A is C36H50N2O7 (MW 622). The antibiotic possesses potent cytocidal activity against HeLa S3 and PLC hepatoma cells at concentrations of 0.1 and 0.01 micrograms/ml (IC50 value) respectively. However, trienomycin A showed no antimicrobial activity against the bacteria, fungi and yeasts examined with the exception of weak activity versus Piricularia oryzae at a concentration of 1,000 micrograms/ml.

Structure-activity relationship of a novel antitumor ansamycin antibiotic trienomycin A and related compounds.

Various derivatives of trienomycin A (1) were prepared and tested for cytocidal activities. All the derivatives except for 22-O-methyltrienomycin A (5) showed reduced cytotoxicity compared with 1. It is concluded that the existence of a triene moiety, free 13-OH and an acyl group at C-11 owe important role for cytocidal activity.

Antitumor effect of kazusamycin B on experimental tumors.

Kazusamycin B, a novel antibiotic (MW 542) isolated from fermentation broth of Streptomyces sp. No. 81-484 showed a broad antitumor spectrum both in vitro and in vivo. IC50 against the growth of tumor cells was around 1 ng/ml at 72 hours-exposure in vitro. Intraperitoneal injection of the antibiotic was effective in inhibiting the growth of murine tumors, S180, P388, EL-4, and B16. It was also active against doxorubicin-resistant P388, hepatic metastases of L5178Y-ML, pulmonary metastases of 3LL, and human mammary cancer MX-1 xenografted to nude mice. However, the activity of kazusamycin B toward L1210 or human lung cancer LX-1 was weaker. According to the results of comparative studies on the effect of kazusamycins B and A, an analog of B, there seemed to be no significant difference in their effectiveness. The effective dose range and toxicity were markedly dependent on tumor lines tested and the regimen used. Maximum tolerated dose in mice with subcutaneous tumors was much higher than that in mice bearing ascitic leukemia as P388. Although intermittent administration could greatly reduce the cumulative toxicity of the drug, therapeutic effect was similar with both successive and intermittent administration schedules.

Kazusamycin B, a novel antitumor antibiotic.

A novel antibiotic, kazusamycin B (C32H46O7, MW 542), was isolated from the fermentation broth of Streptomyces sp. No. 81-484 and the structure was established mainly on the basis of its physico-chemical properties. Unambiguous 13C NMR spectral analysis of kazusamycin B has been also accomplished. Kazusamycin B possesses potent cytocidal activities against L1210 (IC50 0.0018 micrograms/ml) and P388 (IC100 0.0016 micrograms/ml) leukemia cells in vitro.