Dosimetry of Occupational Eye Lens Dose Using a Novel Direct Eye Dosimeter, DOSIRIS, during Interventional Radiology Procedures.

In response to the recommendation by the International Commission on Radiological Protection to lower the equivalent eye dose limit, the Japanese Government in April 2021 lowered the equivalent dose limit for the eye lens for occupational exposure. A considerable number of interventional radiology operators are exposed to levels above the new limit. For this reason, a need exists to more accurately evaluate eye lens dose in interventional radiology operators by using a novel direct eye dosimeter, the DOSIRIS™(IRSN, France), which is capable of measuring a 3-mm dose equivalent under protective glasses. The DOSIRIS is a thermoluminescent dosimeter that exhibits good energy dependence and better directional properties than other dosimeters. Dosimetry using DOSIRIS might be accurate and compatible with the latest regulations.

Simultaneous MR neurography and apparent T2 mapping in brachial plexus: Evaluation of patients with chronic inflammatory demyelinating polyradiculoneuropathy.

PURPOSE: MR neurography is known to be useful to evaluate nerve pathology. The purpose of this study was to evaluate the usefulness of simultaneous apparent T2 mapping and neurography with nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) to distinguish patients with chronic inflammatory demyelinating polyneuropathy (CIDP) from healthy subjects. MATERIALS AND METHODS: This retrospective study included 13 patients with CIDP and five healthy subjects from 2015 to 2017. The T2 relaxation time and the size of the cervical ganglia and roots of the brachial plexus were measured. Statistical analyses were performed with the Mann-Whitney U test and receiver operating characteristics (ROC) analysis. RESULTS: The T2 relaxation times of the ganglia and roots were longer in patients with CIDP (119.31 ±â€¯35.53 msec and 111.15 ±â€¯33.82 msec) than in healthy subjects (101.42 ±â€¯26.42 msec and 85.29 ±â€¯13.22 msec, P = 0.0007 and P < 0.0001, respectively). The sizes of the ganglia and the roots were larger in patients with CIDP (6.25 ±â€¯1.56 mm and 4.37 ±â€¯1.71 mm) than in healthy subjects (5.59 ±â€¯1.08 mm and 3.50 ±â€¯0.62 mm, P = 0.0114 and P = 0.0014, respectively). ROC analysis revealed that T2 relaxation time of the roots was best at distinguishing CIDP patients from healthy subjects (the area under the curve = 0.748). CONCLUSION: Patients with CIDP could be distinguished from healthy subjects using simultaneous apparent T2 mapping and neurography with SHINKEI.

The safety and efficacy of percutaneous vertebroplasty for patients over 90 years old.

OBJECTIVE: To retrospectively analyze the safety and efficacy of percutaneous vertebroplasty (PVP) for patients aged 90 or over. MATERIALS AND METHODS: We analyzed 130 consecutive patients with osteoporotic vertebral fractures who underwent a first-time PVP between May 2015 and September 2017 at our institution. We divided them into the elder patient group aged 90 years or over (n = 21) and the younger patient group under 90 years (n = 109). We compared the two groups' background, treatments, and outcomes using univariate analyzes and the log rank test. RESULTS: A significant difference was observed in dementia (19% in the younger group vs. 48% in the elder group, p < 0.01). No significant difference was revealed in the procedure time or the rate of complications. The post-PVP mobility function and the pain level were significantly improved compared to before PVP in both groups (p < 0.01 each). No significant differences were observed between the two groups in the recurrence of vertebral fracture after treatment (17% vs. 14%) or the 1-year survival rate (79% vs. 86%), respectively. CONCLUSION: The results of our analyzes suggested that a PVP can safely and effectively contribute to pain relief as well as the restoration of ambulation for patients aged 90 or over.

Ultrahigh-resolution CT scan of the temporal bone.

OBJECTIVE: Ultrahigh-resolution CT (U-HRCT) provides better spatial resolution than conventional multi-detector row CT (ConvCT) and could be expected to identify microstructures with its 0.25-mm collimation, 1792 channels and 160 detector rows, 0.4 × 0.5 mm focus size, and a 1024 matrix. The aim of the study was to evaluate key anatomic structures in temporal bone using U-HRCT comparing it to ConvCT. MATERIALS AND METHODS: A total of 30 patients (14 males and 16 females; age range, 8-82 years; median 49 years) underwent both U-HRCT and ConvCT. All CT images were obtained with 0.5 mm section thickness and a 512 × 512 matrix, and field of view of 80 mm. Transverse scans were acquired in a plane parallel to the orbitomeatal plane in the helical mode with 120 kV. Images of the 30 temporal bones of unaffected side were reviewed by two independent neuroradiologists who rated the visibility of key anatomic structures for both U-HRCT and ConvCT. The ratings between U-HRCT and ConvCT were compared using Wilcoxon matched-pairs signed rank test. The interobserver agreement on the rating of stapedius tendon was evaluated using weighted κ statistics. RESULTS: Excellent interobserver agreement was shown for U-HRCT (κ = 0.920), whereas good agreement was obtained for ConvCT (κ = 0.733). According to both observers, stapedius tendon was more clearly visualized using U-HRCT than ConvCT (p < 0.0001). All other anatomic structures were well visualized using both CT scanners. CONCLUSION: The anatomy of temporal bone is more conspicuous on U-HRCT than on ConvCT because of its ultra-high-resolution detector. U-HRCT may provide beneficial information for determining surgical indication or procedures.

Lumbar plexus in patients with chronic inflammatory demyelinating polyradiculoneuropathy: evaluation with simultaneous T2 mapping and neurography method with SHINKEI.

OBJECTIVE:: To evaluate the usefulness of simultaneous T2 mapping and neurography with nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) in the lumbar plexus to distinguish patients with chronic inflammatory demyelinating polyneuropathy (CIDP) from healthy controls. METHODS:: Our institutional review boards approved this retrospective study, and written informed consent was waived. 10 patients with CIDP from 2015 to 2017 were studied along with 5 healthy controls on a 3 T scanner. The T2 relaxation time and the size of the dorsal root ganglia and nerves of the lumbar plexus at L3-S1 were measured. Statistical analyses were performed with the Mann-Whitney U test and a receiver operating characteristics analysis. RESULTS:: The T2 relaxation times of the dorsal root ganglia and the nerves of the lumbar plexus were longer in the CIDP patients (133.34 ± 41.36 and 130.40 ± 47.78 ms) compared to the healthy controls (114.69 ± 24.90 and 83.72 ± 17.51 ms, p = 0.0265 and p < 0.0001, respectively). The sizes of the nerves were larger in the CIDP patients (6.19 ± 2.28 mm) compared to the controls (4.54 ± 0.86 mm, p < 0.0001). However, there was no significant difference between the sizes of the ganglia in the CIDP patients and the controls. The receiver operating characteristics analysis revealed that the T2 relaxation time of the nerves was best at distinguishing the CIDP patients from the controls (Az = 0.848). CONCLUSION:: Patients with CIDP could be distinguished from healthy controls using simultaneous T2 mapping and neurography with SHINKEI in the lumbar plexus. ADVANCES IN KNOWLEDGE:: Patients with CIDP could be distinguished from healthy controls using simultaneous T2 mapping and neurography with SHINKEI in the lumbar plexus.

High-yield production and characterization of biologically active recombinant aprotinin expressed in Saccharomyces cerevisiae.

Aprotinin is a polypeptide composed of 58 amino acid residues and has a molecular weight of 6512Da. The 58 amino acid residues are arranged in a single polypeptide chain, which is cross-linked by three disulfide bridges and folded to form a pear-shaped molecule. To express recombinant aprotinin in Saccharomyces cerevisiae, a synthetic gene encoding aprotinin was constructed and fused in frame with the pre-sequence of the S. cerevisiae MATalpha1 gene at the cleavage site of signal peptidase. The expression of aprotinin in S. cerevisiae was carried out using the PRB1 promoter. Aprotinin was secreted as a biologically active protein at a concentration of 426 mg/L into high cell density fermentation medium of 70.9 g/L cell dry weight. The purification process consisted of only three major steps and provided consistent yields of recombinant aprotinin using gel filtration high-pressure liquid chromatographic (HPLC) with a purity level higher than 99% and was free of non-aprotinin-related impurities. The recombinant aprotinin had the same characteristics as bovine aprotinin in a number of analytical methods, including alpha2-plasmin inhibition assay, amino acid composition, N-terminal amino acid sequence determination, and mass spectrum analysis. With further optimization of the purification process and culture conditions for high-yield production by S. cerevisiae, this source of recombinant aprotinin may be a promising approach for the commercial manufacture of aprotinin for pharmaceutical use instead of bovine aprotinin.

Preparation of recombinant murine tumor necrosis factor-alpha in Escherichia coli: a rapid method to remove tags from fusion proteins by thrombin-cleavage and ion-exchange chromatography.

A recombinant protein of murine tumor necrosis factor (TNF)-alpha was expressed in Escherichia coli (E. coli) by using a pET Trx Fusion System. The fusion protein was effectively solubilized and purified by Ni-affinity chromatography. A high concentration of thrombin quickly and specifically cleaved the introduced site between the tags and the target fragment. We found that thrombin tightly bound to an ion-exchange resin, CM-Sepharose, under conditions avoiding adsorption of most proteins. By passing through the column, thrombin was quickly removed from the reaction mixtures. These methods appear to be widely potentially useful to remove the tags from recombinant fusion proteins. Prepared recombinant TNF demonstrated cytotoxic effects to L929 cells at very low concentrations with an EC50 value of 0.19+/-0.02 pM. In addition, immunization of a rabbit with the protein induced a neutralizing antibody. The methods used in this study appear to be useful to prepare significant amount of soluble functional recombinant proteins in E. coli.

Comparison of lipopolysaccharide-binding functions of CD14 and MD-2.

Prior to being recognized by the cell surface Toll-like receptor 4/MD-2 complex, lipopolysaccharide (LPS) in the bacterial outer membrane has to be processed by LPS-binding protein and CD14. CD14 forms a complex with monomeric LPS extracted by LPS-binding protein and transfers LPS to the cell surface signaling complex. In a previous study, we prepared a functional recombinant MD-2 using a bacterial expression system. We expressed the recombinant protein in Escherichia coli as a fusion protein with thioredoxin and demonstrated specific binding to LPS. In this study, we prepared recombinant CD14 fusion proteins using the same approach. Specific binding of LPS was demonstrated with a recombinant protein containing 151 amino-terminal residues. The region contained a hydrophilic region and the first three leucine-rich repeats (LRRs). The LRRs appeared to contribute to the binding because removal of the region resulted in a reduction in the binding function. LPS binding to the recombinant MD-2 was resistant to detergents. On the other hand, the binding to CD14 was prevented in the presence of low concentrations of detergents. In the case of human MD-2, the secondary myristoyl chain of LPS added by LpxM was required for the binding. A nonpathogenic penta-acyl LPS mutant lacking the myristoyl chain did not bind to MD-2 but did so normally to CD14. The broader LPS-binding spectrum of CD14 may allow recognition of multiple pathogens, and the lower affinity for LPS binding of CD14 allows transmission of captured materials to MD-2.

The functional and structural properties of MD-2 required for lipopolysaccharide binding are absent in MD-1.

MD-1 and MD-2 are secretory glycoproteins that exist on the cell surface in complexes with transmembrane proteins. MD-1 is anchored by radioprotective 105 (RP105), and MD-2 is associated with TLR4. In vivo studies revealed that MD-1 and MD-2 have roles in responses to LPS. Although the direct binding function of MD-2 to LPS has been observed, the physiological function of MD-1 remains unknown. In this study, we compared the LPS-binding functions of MD-1 and MD-2. LPS binding to cell surface complexes was detected for cells transfected with TLR4/MD-2. In contrast, binding was not observed for RP105/MD-1-transfected cells. When rMD-2 protein was expressed in Escherichia coli, it was purified in complexes containing LPS. In contrast, preparations of MD-1 did not contain LPS. When rMD-2 protein was prepared in a mutant strain lacking the lpxM gene, LPS binding disappeared. Therefore, the secondary myristoyl chain attached to the (R)-3-hydroxymyristoyl chain added by LpxM is required for LPS recognition by MD-2, under these conditions. An amphipathic cluster composed of basic and hydrophobic residues in MD-2 has been suggested to be the LPS-binding site. We specifically focused on two Phe residues (119 and 121), which can associate with fatty acids. A mutation at Phe(191) or Phe(121) strongly reduced binding activity, and a double mutation at these residues prevented any binding from occurring. The Phe residues are present in MD-2 and absent in MD-1. Therefore, the LPS recognition mechanism by RP105/MD-1 is distinct from that of TLR4/MD-2.

Preparation of recombinant alpha-thrombin: high-level expression of recombinant human prethrombin-2 and its activation by recombinant ecarin.

We have established a large-scale manufacturing system to produce recombinant human alpha-thrombin. In this system, a high yield of alpha-thrombin is prepared from prethrombin-2 activated by recombinant ecarin. We produced human prethrombin-2 using mouse myeloma cells and an expression plasmid carrying the chicken beta-actin promoter and mutant dihydrofolate reductase gene for gene amplification. To increase prethrombin-2 expression further, we performed fed-batch cultivation with the addition of vegetable peptone in 50 liters of suspension culture. After five feedings of vegetable peptone, the expression level of the recombinant prethrombin-2 reached 200 micro g/ml. Subsequently, the recombinant prethrombin-2 could be activated to alpha-thrombin by recombinant ecarin expressed in a similar manner. Finally, recombinant alpha-thrombin was purified to homogeneity by affinity chromatography using a benzamidine-Sepharose gel. The yield from prethrombin-2 in culture medium was approximately 70%. The activity of the purified recombinant alpha-thrombin, including hydrolysis of a chromogenic substrate, release of fibrinopeptide A, and activation of protein C, was indistinguishable from that of plasma-derived alpha-thrombin. Our system is suitable for the large-scale production of recombinant alpha-thrombin, which can be used in place of clinically available alpha-thrombin derived from human or bovine plasma.