Development of Medical Shark Skin Forceps: Improved Grasping Power and Easy Manipulation

Background and Objectives

Important safety requirements for forceps used in surgical procedures are the ability to stably grasp fine tissue and to cause minimal tissue damage. Shark skin has the structural feature of circumpolar scales, which increase the frictional force of the scales by roughening their surface. We have developed and patented medical forceps with a shark skin pattern placed on the tip surfaces. The aim of this study was to examine the safety and efficacy of the shark skin forceps compared with existing forceps, both fundamentally and clinically.

Methods

To evaluate gripping power and usability, we compared bead transfer times for each forceps type. Grasping force and frictional force were measured quantitatively and compared among the types. To evaluate safety, we performed pathological examination of lung and urethral tissue after grasping, in an animal experiment. Subjective assessment of user experience was then performed using a questionnaire.

Results

In the dry lab assessment, transfer time was fastest using the shark skin forceps (34 s vs 61 s and 62 s, p < 0.05). Frictional force values were highest for the shark skin forceps (p < 0.05). In the animal experiment, there was no difference in pathological tissue damage to lung or ureter tissues among the forceps types after grasping. The questionnaire responses indicated advantages of the shark skin forceps in terms of ease of grasping membranes and lower degree of grasp failure.

Conclusion

Forceps with shark skin on the tips showed greater stability of tissue grasping and equivalent safety compared with existing forceps.

Development and evaluation of an original phantom model of ultrasonography-guided thyroid gland biopsy for the training of surgical residents and students

PURPOSES

Fine-needle aspiration cytology (FNAC) is a specific and important test used for the diagnosis of thyroid gland cancer. We developed a thyroid gland phantom using original manufacturing techniques and direct three-dimensional (3D) printing. The aim of this study was to confirm the effectiveness of this phantom by collecting data to evaluate puncture training.

METHODS

Data from 45 ultrasonography-guided thyroid nodule FNAC procedures performed on our thyroid phantom were evaluated in our department. The first group comprised qualified physicians who specialized in thyroid gland treatment (group A; n = 10). The second and third groups comprised senior and junior residents (group B; n = 8 and group C; n = 12; respectively). The fourth group comprised students (group D; n = 15). We measured the times taken by these groups to complete each task.

RESULTS

The skills of all participants in groups B, C, and D improved after using this phantom involving the major (parallel)- (0.47 ± 0.07) and short (orthogonal)-axes (0.52 ± 0.07) methods (P < 0.001). The number of erroneous punctures decreased from 53 to 3.

CONCLUSIONS

Our original phantom improved the puncture skills of students and junior doctors and was suitable as a tailored training model for practicing thyroid gland transfixion.

Application of the sliding window method and Mask-RCNN method to nuclear recognition in oral cytology

Background

We aimed to develop an artificial intelligence (AI)-assisted oral cytology method, similar to cervical cytology. We focused on the detection of cell nuclei because the ratio of cell nuclei to cytoplasm increases with increasing cell malignancy. As an initial step in the development of AI-assisted cytology, we investigated two methods for the automatic detection of cell nuclei in blue-stained cells in cytopreparation images.

Methods

We evaluated the usefulness of the sliding window method (SWM) and mask region-based convolutional neural network (Mask-RCNN) in identifying the cell nuclei in oral cytopreparation images. Thirty cases of liquid-based oral cytology were analyzed. First, we performed the SWM by dividing each image into 96 × 96 pixels. Overall, 591 images with or without blue-stained cell nuclei were prepared as the training data and 197 as the test data (total: 1,576 images). Next, we performed the Mask-RCNN by preparing 130 images of Class II and III lesions and creating mask images showing cell regions based on these images.

Results

Using the SWM method, the highest detection rate for blue-stained cells in the evaluation group was 0.9314. For Mask-RCNN, 37 cell nuclei were identified, and 1 cell nucleus was identified as a non-nucleus after 40 epochs (error rate:0.027).

Conclusions

Mask-RCNN is more accurate than SWM in identifying the cell nuclei. If the blue-stained cell nuclei can be correctly identified automatically, the entire cell morphology can be grasped faster, and the diagnostic performance of cytology can be improved.

Research on automatic preprocessing equipment of salivary analyte for PCR inspection of coronavirus

Polymerase chain reaction (PCR) inspection of salivary analyte is performed by pretreatment, RNA extraction setup, RNA extraction, PCR setup, and the PCR process. However, the pretreatment process is conducted manually, and it is a bottleneck to the overall process. The author created automatic preprocessing logistics and prototypes using robotic technology for the pretreatment process. A dissolving agent of saliva is poured into the salivary container, the transfer syringe is automated, and a transfer robot injects an inactivating solubilizer using a robotic hand. Ninety-six inactivated vessel units are processed for the next RNA extraction process. The automatic preprocessing equipment is successfully developed and used in the inspection at a hospital. Pretreatment efficiency is up to eight times greater compared to that with the conventional manual process. The 96 units/h inspection is made possible by a single of equipment. The developed automatic preprocessing method assures high efficiency, standardization, and safety for coronavirus inspection.

Evaluation of laparoscopic forceps jaw contact pressure and distribution using pressure sensitive film

In this study, the authors used the Fujifilm Prescale Pressure Measuring System to measure the contact pressure and distribution at the jaws of laparoscopic grasping forceps. This data was then correlated with measured pressures at the forceps handles to understand the relationship between the surgeon's actuating pressure and that on the organ being manipulated. The purpose of this study is to create a database of tactile information to provide guidelines in defining minimally invasive surgery (MIS). This is expected to be important as today's society continues to progress in the use of automation, IoT, AI and MIS. In order to achieve the above, the authors developed an experimental device consisting of an actuator, a load cell and an MCU to stably actuate and control the handle side of grasping forceps. Target organs were simulated using triangular prisms of various silicone rubber materials. The experimental method involved actuating the handle side with preset pressure values for fixed time periods and using sensitive film to measure the pressure at the forceps tip. The film data was then scanned, processed and analyzed.

New Concept for a Thoracic Drainage System Using Magnetic Actuation

Objectives. Thoracic drainage is a common procedure to drain fluid, blood, or air from the pleural cavity. Some attempts to develop approaches to new thoracic drainage systems have been made; however, a simple tube is often currently used. The existing drain presupposes that it is placed correctly and that the tip does not require moving after insertion into the thoracic cavity. However, in some cases, the drain is not correctly placed and reinsertion of an additional drain is required, resulting in significant invasiveness to the patient. Therefore, a more effective drainage system is needed. This study aimed to develop and assess a new thoracic drain via a collaboration between medical and engineering personnel. Methods. We developed the concept of a controllable drain system using magnetic actuation. A dry laboratory trial and accompanying questionnaire assessment were performed by a group of thoracic and general surgeons. Objective mechanical measurements were obtained. Porcine experiments were also carried out. Results. In a dry laboratory trial, use of the controllable drain required significantly less time than that required by replacing the drain. The average satisfaction score of the new drainage system was 4.07 out of 5, indicating that most of the research participants were satisfied with the quality of the drain with a magnetic actuation. During the porcine experiment, the transfer of the tip of the drain was possible inside the thoracic cavity and abdominal cavity. Conclusion. This controllable thoracic drain could reduce the invasiveness for patients requiring thoracic or abdominal cavity drainage.

∆9-Tetrahydrocannabinol, a major marijuana component, enhances the anesthetic effect of pentobarbital through the CB1 receptor

Purpose

∆⁹-Tetrahydrocannabinol (∆⁹-THC) and cannabidiol (CBD), major psychoactive constituents of marijuana, induce potentiation of pentobarbital-induced sleep in mice. We have elucidated the mechanism of enhancement of the anesthetic effect of pentobarbital by cannabinoids.

Methods

We carried out pharmacological experiment and cannabinoid₁ (CB₁) receptor binding assay using CB₁ antagonists to clarify whether the CB₁ receptor is involved in the synergism or not. The affinities of cannabinoids for the CB₁ receptor in the mouse brain synaptic membrane were evaluated using a specific CB₁ ligand, [³H]CP55940.

Results

Although the potentiating effect of ∆⁹-THC on pentobarbital-induced sleep was attenuated by co-administration of CB₁ receptor antagonists, such as SR141716A and AM251, at a dose of 2 mg/kg, intravenously (i.v.) to mice, the CBD-enhanced pentobarbital-induced sleep was not inhibited by SR141716A. The inhibitory constant (Ki) values of ∆⁹-THC and CBD were 6.62 and 2010 nM, respectively, showing a high affinity of ∆⁹-THC and a low affinity of CBD for the CB₁ receptor, respectively. A high concentration of pentobarbital (1 mM) did not affect specific [³H]CP55940 binding on the mouse brain synaptic membrane.

Conclusions

These results suggest that binding of ∆⁹-THC to the CB₁ receptor is involved in the synergism with pentobarbital, and that potentiating effect of CBD with pentobarbital may differ from that of ∆⁹-THC. We successfully demonstrated that ∆⁹-THC enhanced the anesthetic effect of pentobarbital through the CB₁ receptor.

Balloon-Based Organ Retractor With Increased Safety and Reduced Invasiveness During Video-Assisted Thoracoscopic Surgery

OBJECTIVES

In recent years, video-assisted thoracoscopic surgery (VATS) has increasingly become the preferred technique for thoracic surgery. However, the inherent characteristics of the lungs as large, soft, slippery, and delicate creates difficulties for pulmonary surgery. In this article, we outline the development and assessment of a balloon-based organ retractor for VATS via collaboration between medical and engineering personnel.

METHODS

A dry lab trial and accompanying questionnaire assessment were performed by a group of thoracic surgeons. Objective pressure measurements were obtained, and animal experiment on pigs was performed.

RESULTS

In the dry lab trial, use of the developed organ retractor required significantly less time and resulted in fewer difficulties than using a Cherry Dissector. The measured pressure per mm² of the developed retractor was clearly lower than that for the Cherry Dissector. The questionnaire completed by the surgeons following the dry lab and animal experiments showed that most of the surgeons (7 surgeons out of 9) were satisfied with the quality of the balloon-based retractor based on a score of 3.13 ± 0.28 (mean ± standard deviation) out of 4.0. During the animal experiment, the balloon-based retractor provided stable and clear viewing with minimal need for adjustment.

CONCLUSION

This balloon-based retractor could contribute to increased safety and less-invasive VATS.

Evaluation of Line Immunoassay to Detect HTLV-1 Infection in an Endemic Area, Southwestern Japan; Comparison with Polymerase Chain Reaction and Western Blot

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) has been recognized as a cause of adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy/tropical spastic paraparesis, and HTLV-1-associated uveitis. HTLV-1 infection is normally detected by screening for HTLV-1 antibodies, and positive samples are confirmed by Western blot (WB). However, WB fails to confirm some samples that were positive for HTLV-1 antibodies on screening. Line immunoassay (LIA) is commonly used in Europe and Brazil, but not in Japan. Therefore, we evaluated the performance of LIA as a method of confirming HTLV-1 antibodies using samples in Japan.

METHODS

LIA was compared with polymerase chain reaction (PCR) and WB using 50 negative and 70 positive samples tested by chemiluminescent enzyme immunoassay (CLEIA) in Miyazaki, Japan, an HTLV-1 endemic area. LIA (INNO-LIA HTLVI/II Score) and WB (Problot HTLV-I) were performed according to the manufacturer's instructions. Real-time PCR for HTLV-1 pX region was performed using DNA derived from white blood cells. The samples that tested negative by real-time PCR were further tested by nested PCR.

RESULTS

All 50 CLEIA negative samples were determined to be negative by LIA and PCR. Of the 70 positive samples, 66 tested positive by both of LIA and PCR. Three samples tested negative by LIA and PCR, and the remaining sample (PCR negative) showed non-specific staining in LIA and WB. WB showed more indeterminate results than LIA. Gp21 antibody in LIA demonstrated a high ability to discriminate between positive and negative PCR results. Furthermore, the degree of gp21 antibody reaction by LIA showed correlation with HTLV-1 proviral loads (PVLs).

CONCLUSIONS

Our results indicate that LIA performs well in confirming HTLV-1 seropositivity by showing a low incidence of indeterminate results and good agreement with PCR using samples in Japan, although the number of samples tested was small. In addition, semi-quantitative antibody titer to gp21 correlated well with HTLV-1 PVLs. Further study including larger samples is necessary to determine the positioning of LIA for HTLV-1 detection in Japan.

Development of a simple and practical method of discrimination between Vibrio furnissii and V. fluvialis based on single-nucleotide polymorphisms of 16S rRNA genes observed in V. furnissii but not in V. fluvialis

Vibrio furnissii and V. fluvialis are closely related, the discrimination of which by conventional biochemical assay remains a challenge. Investigation of the sequence of the 16S rRNA genes in a clinical isolate of V. furnissii by visual inspection of a sequencing electropherogram revealed two sites of single-nucleotide polymorphisms (SNPs; positions 460 A/G and 1261 A/G) in these genes. A test of 12 strains each of V. fluvialis and V. furnissii revealed these SNPs to be common in V. furnissii but not in V. fluvialis. Divergence of SNP frequency was observed among the strains of V. furnissii tested. Because the SNPs described in V. furnissii produce a difference in the target sequence of restriction enzymes, a combination of polymerase chain reaction (PCR) of the 16S rRNA genes using conventional primers and restriction fragment length polymorphism analysis using Eco RV and Eae I was shown to discriminate between V. fluvialis and V. furnissii. This method is simple and alleviates the need for expensive equipment or primer sets specific to these bacteria. Therefore, we believe that this method can be useful, alongside specific PCR and mass spectrometry, when there is a need to discriminate between V. fluvialis and V. furnissii.

Tongue-palatal contact changes in patients with skeletal mandibular prognathism after sagittal split ramus osteotomy: an electropalatography study

The purpose of this study was to investigate the changes in tongue-palatal contact patterns using electropalatography (EPG) before and after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Nine clients who underwent SSRO for mandibular setback and seven control subjects were participated in this study. Tongue-palatal contact patterns for /t/, /s/ and /k/ production were investigated using EPG before surgery and 3 months after surgery. The mean value of whole total of palate contact (WT) in the maximum contact frame was examined before and after SSRO. The correlation quantity between the change of center of gravity (COG) value and the amount of mandibular setback was also evaluated. The mean value of WT for /t/ and /s/ significantly increased after SSRO, and the EPG pattern became normal. However, a remarkable change in WT for /k/ was not observed, and the mean value was significantly larger in the SSRO group before and after surgery than in the control group. A negative correlation between COG variation and the amount of mandibular setback for /t/ and positive correlation for /s/ was observed. This study demonstrated that tongue-palatal contact patterns for /t/ and /s/ articulation improved clearly after SSRO. There was a significant correlation between COG variation and the amount of mandibular setback. However, no significant change was detected through perceptual assessment before and after SSRO. Further investigation is needed to determine whether these results will change over time.

Clinicopathologic Impact of Early Medullary Ray Injury in Patients Following Kidney Transplantation

BACKGROUND

Previously, we explored the histopathologic characteristics of medullary ray injury (MRI) inducing interstitial fibrosis and tubular atrophy (IF/TA) to determine its etiologies, which include calcineurin inhibitor (CNI) toxicity and urologic complications. However, we did not examine the effects of these etiologies on long-term kidney allograft prognosis, because biopsy timing differed among cases.

AIM

We examined the influence of early MRI on kidney allograft prognosis using protocol biopsies taken within a 3-month time frame.

METHODS

We defined early MRI as tubular degeneration with interstitial edema or mild fibrosis localized to the medullary ray. We divided 53 protocol biopsies into 2 groups, with and without early MRI. Early MRI+ cases with isometric vacuolization were classified as CNI toxicity; those with Tamm-Horsfall protein in the interstitium and a thyroidlike appearance were classified as urinary tract system abnormalities; remaining cases were classified as "others." We compared changes in serum levels of creatinine (sCr) over 3 years and fibrosis extent at 1 year.

RESULTS

The sCr levels were significantly higher in the MRI+ group than the MRI- group at 3 years (P = .024). Examining the 3 MRI+ subgroups, only the MRI+ urinary tract system abnormalities group had significantly high sCr levels compared to the MRI- group (P = .019). The MRI+ group showed significant signs of IF/TA at 1 year.

CONCLUSIONS

Early MRI after kidney transplantation was significantly more likely to develop IF/TA at 1 year and had higher sCr levels at 3 years. In such cases, intervention might preserve graft function over the long term.

A Ferromagnetic Foreign Body at the Lateral Aspect of the Mandibular Ramus in a Medically Compromised Patient

A case of a ferromagnetic foreign body in a medically compromised patient was reported. The patient was a 45-year-old male who consulted our department complaining of a foreign body accidentally impacted in the right cheek. X-ray examination revealed a foreign body at the lateral aspect of the right mandibular ramus. The removal of the foreign body was scheduled, but the patient did not return for the procedure. After 8 years he revisited our department for the removal of the foreign body, because it had been found to be ferromagnetic and a barrier to MRI examination. X-ray examination confirmed the foreign body was located at the same site as 8 years prior. Although the patient was suffering from liver cirrhosis with thrombocytopenia and leukopenia, the foreign body was successfully removed under general anesthesia. The foreign body was 12 × 5 × 1 mm, weighed 0.48 g, and was ferromagnetic. The patient’s postoperative course was uneventful. X-ray examination confirmed the removal of the foreign body. Since the surgery, the patient has been in generally stable condition with no complications. This case was a rare example of a foreign body that needed to be removed for medical examination.

Research on seamless development of surgical instruments based on biological mechanisms using CAD and 3D printer

In the area of manufacturing surgical instruments, the ability to rapidly design, prototype and test surgical instruments is critical. This paper provides a simple case study of the rapid development of two bio-mechanism based surgical instruments which are ergonomic, aesthetic and were successfully designed, prototyped and conceptually tested in a very short period of time.

Development of wrist rehabilitation robot and interface system

The authors have developed a practical wrist rehabilitation robot for hemiplegic patients. It consists of a mechanical rotation unit, sensor, grip, and computer system. A myoelectric sensor is used to monitor the extensor carpi radialis longus/brevis muscle and flexor carpi radialis muscle activity during training. The training robot can provoke training through myoelectric sensors, a biological signal detector and processor in advance, so that patients can undergo effective training of extention and flexion in an excited condition. In addition, both-wrist system has been developed for mirror effect training, which is the most effective function of the system, so that autonomous training using both wrists is possible. Furthermore, a user-friendly screen interface with easily recognizable touch panels has been developed to give effective training for patients. The developed robot is small size and easy to carry. The developed aspiring interface system is effective to motivate the training of patients. The effectiveness of the robot system has been verified in hospital trails.

Cannabidiol induces expression of human cytochrome P450 1A1 that is possibly mediated through aryl hydrocarbon receptor signaling in HepG2 cells

AIMS

We herein investigated the inducibility of cytochrome P450 1A1 (CYP1A1) by Δ(9)-tetrahydrocannabinol, cannabidiol (CBD), and cannabinol, three major phytocannabinoids, using human hepatoma HepG2 cells.

MAIN METHODS

The expression of CYP1A1 and the aryl hydrocarbon receptor (AhR) was measured by a quantitative real-time polymerase chain reaction and/or Western blotting.

KEY FINDINGS

Δ(9)-Tetrahydrocannabinol and CBD concentration-dependently induced the expression of CYP1A1 mRNA, whereas cannabinol showed little or no induction. Among the phytocannabinoids tested, CBD was the most potent inducer of CYP1A1 expression. The induction of CYP1A1 expression by CBD was significantly attenuated by the knockdown of AhR expression with AhR small interfering RNAs. The role of protein tyrosine kinases (PTKs) in the CBD-mediated induction of CYP1A1 was then examined using herbimycin A, a PTK inhibitor. The upregulation of CYP1A1 by CBD was significantly suppressed by herbimycin A as was the induction by omeprazole but not 3-methylcholanthrene. The inducibility of CYP1A1 by CBD-related compounds was examined to clarify the structural requirements for CBD-mediated CYP1A1 induction. Olivetol, which corresponds to the pentylresorcinol moiety of CBD, significantly induced the expression of CYP1A1, whereas d-limonene, CBD-2'-monomethyl ether, and CBD-2',6'-dimethyl ether did not.

SIGNIFICANCE

These results showed that CBD may have induced human CYP1A1 expression through the activation of PTK-dependent AhR signaling, in which two phenolic hydroxyl groups in the pentylresorcinol moiety of CBD may play structurally important roles.

Aging effect on plasma metabolites and hormones concentrations in riding horses

Age effects on plasma metabolites, hormone concentrations, and enzyme activities related to energy metabolism were investigated in 20 riding horses. Animals were divided into two groups: young (3-8 years) and aged (11-18 years). They were clinically healthy, and not obese. Plasma adiponectin (ADN) concentrations in aged horses were significantly lower than those in young horses (mean±SE, 6.5±1.3 µg mL-1 vs, 10.9±1.7 µg mL-1, Mann-Whitney U test, respectively; P=0.0233). Plasma non-esterified fatty acid levels and Insulin and malondialdehyde concentrations in aged group tended to increase compared to those in young group although there were not significant differences statistically. In aged group, malate dehydrogenase/lactate dehydrogenase (M/L) ratio, which is considered an energy metabolic indicator, did not change significantly compared to that in young group. Present data suggest that aging may negatively affect nutrition metabolism, but not induce remarkable changes in M/L ratio in riding horses.

Aging effect on plasma metabolites and hormones concentrations in riding horses

Age effects on plasma metabolites, hormone concentrations, and enzyme activities related to energy metabolism were investigated in 20 riding horses. Animals were divided into two groups: Young (3-8 years) and aged (11-18 years). They were clinically healthy, and not obese. Plasma adiponectin (ADN) concentrations in aged horses were significantly lower than those in young horses (mean±SE, 6.5±1.3 µg mL(-1) vs, 10.9±1.7 µg mL(-1), Mann-Whitney U test, respectively; P=0.0233). Plasma non-esterified fatty acid levels and Insulin and malondialdehyde concentrations in aged group tended to increase compared to those in young group although there were not significant differences statistically. In aged group, malate dehydrogenase/lactate dehydrogenase (M/L) ratio, which is considered an energy metabolic indicator, did not change significantly compared to that in young group. Present data suggest that aging may negatively affect nutrition metabolism, but not induce remarkable changes in M/L ratio in riding horses.

Spin-chirality-driven ferroelectricity on a perfect triangular lattice antiferromagnet

Magnetic field (B) variation of the electrical polarization P(c) (∥c) of the perfect triangular lattice antiferromagnet RbFe(MoO(4))(2) is examined up to the saturation point of the magnetization for B⊥c. P(c) is observed only in phases for which chirality is predicted in the in-plane magnetic structures. No strong anomaly is observed in P(c) at the field at which the spin modulation along the c axis, and hence the spin helicity, exhibits a discontinuity to the commensurate state. These results indicate that the ferroelectricity in this compound originates predominantly from the spin chirality, the explanation of which would require a new mechanism for magnetoferroelectricity. The obtained field-temperature phase diagram of ferroelectricity agree well with those theoretically predicted for the spin chirality of a Heisenberg spin triangular lattice antiferromagnet.

A hydrophobic area of the GABA ρ₁ receptor containing phenylalanine 124 influences both receptor activation and deactivation

Experimental evidence suggests that GABA ρ1 receptors are potential therapeutic targets for the treatment of a range of neurological conditions, including anxiety and sleep disorders. Homology modelling of the GABA ρ1 extracellular N-terminal domain has revealed a novel hydrophobic area that extends beyond, but not including the GABA-binding site. Phenylalanine 124 (F124) is predicted to be involved in maintaining the structural integrity of the orthosteric-binding site. We have assessed the activity of a series of GABA ρ1 receptors that incorporate a mutation at F124. Wild-type and mutant human GABA ρ1 subunits were expressed in Xenopus laevis oocytes and AD293 cells, and the pharmacology and kinetic properties of the receptors were measured using electrophysiological analysis. Mutation of F124 had minimal effect on receptor pharmacology. However, the rate of deactivation was significantly increased compared to wild type. This study provides further information about the role of residues within a novel hydrophobic area of the GABA ρ1 receptor. This knowledge can help future studies into the design of potent and subtype-selective ligands with therapeutic value.

Characterization of the structural determinants required for potent mechanism-based inhibition of human cytochrome P450 1A1 by cannabidiol

We previously demonstrated that cannabidiol (CBD) was a potent mechanism-based inhibitor of human cytochrome P450 1A1 (CYP1A1). However, the moiety of CBD that contributes to the potent mechanism-based inhibition of human CYP1A1 remains unknown. Thus, the effects of compounds structurally related to CBD on CYP1A1 activity were examined with recombinant human CYP1A1 in order to characterize the structural requirements for potent inactivation by CBD. When preincubated in the presence of NADPH for 20min, olivetol, which corresponds to the pentylresorcinol moiety of CBD, enhanced the inhibition of the 7-ethoxyresorufin O-deethylase activity of CYP1A1. In contrast, d-limonene, which corresponds to the terpene moiety of CBD, failed to inhibit CYP1A1 activity in a metabolism-dependent manner. Pentylbenzene, which lacks two free phenolic hydroxyl groups, also did not enhance CYP1A1 inhibition. On the other hand, preincubation of the CBD-2'-monomethyl ether (CBDM) and CBD-2',6'-dimethyl ether (CBDD) enhanced the inhibition of CYP1A1 activity. Inhibition by cannabidivarin (CBDV), which possessed a propyl side chain, was strongly potentiated by its preincubation. Orcinol, which has a methyl group, augmented CYP1A1 inhibition, whereas its derivative without an alkyl side chain, resorcinol, did not exhibit any metabolism-dependent inhibition. The preincubation of CBD-hydroxyquinone did not markedly enhance CYP1A1 inhibition. We further confirmed that olivetol, CBDM, CBDD, CBDV, and orcinol, as well as CBD (kinact=0.215min(-1)), inactivated CYP1A1 activity; their kinact values were 0.154, 0.0638, 0.0643, 0.226, and 0.0353min(-1), respectively. These results suggest that the methylresorcinol structure in CBD may have structurally important roles in the inactivation of CYP1A1.

Research and development of compact wrist rehabilitation robot system

Compact rehabilitation robot system which can support movement of the wrist of patients has been developed. The robot system can detect and analyze the patient's intention to move the wrist by such a biological signal as muscle potential, then, assist the wrist exercise of patients. Also, both-wrist rehabilitation robot system by mirror effect has been successfully developed for practical use in the hospital and at home.

Structural requirements for potent direct inhibition of human cytochrome P450 1A1 by cannabidiol: role of pentylresorcinol moiety

Our recent work has shown that cannabidiol (CBD) exhibits the most potent direct inhibition of human cytochrome P450 1A1 (CYP1A1) among the CYP enzymes examined. However, the mechanism underlying this CBD inhibition remains to be clarified. Thus, to elucidate the structural requirements for the potent inhibition by CBD, the effects of CBD and its structurally related compounds on CYP1A1 activity were investigated with recombinant human CYP1A1. Olivetol, which corresponds to the pentylresorcinol moiety of CBD, inhibited the 7-ethoxyresorufin O-deethylase activity of CYP1A1; its inhibitory effect (IC50=13.8 µM) was less potent than that of CBD (IC50=0.355 µM). In contrast, d-limonene, which corresponds to the terpene moiety of CBD, only slightly inhibited CYP1A1 activity. CBD-2'-monomethyl ether (CBDM) and CBD-2',6'-dimethyl ether inhibited CYP1A1 activity with IC50 values of 4.07 and 23.0 µM, respectively, indicating that their inhibitory effects attenuated depending on the level of methylation on the free phenolic hydroxyl groups in the pentylresorcinol moiety of CBD. Cannabidivarin inhibited CYP1A1 activity, although its inhibitory potency (IC50=1.85 µM) was lower than that of CBD. The inhibitory effects of Δ(9)-tetrahydrocannabinol and cannabielsoin (IC50s ≈10 µM), which contain a free phenolic hydroxyl group and are structurally constrained, were less potent than that of CBDM, which contains a free phenolic hydroxyl group and is rotatable between pentylresorcinol and terpene moieties. These results suggest that the pentylresorcinol structure in CBD may have structurally important roles in direct CYP1A1 inhibition, although the whole structure of CBD is required for overall inhibition.

Topological phase transitions driven by magnetic phase transitions in Fe(x)Bi2Te3 (0≤x≤0.1) single crystals

We propose a phase diagram for Fe(x)Bi2Te3 (0≤x≤0.1) single crystals, which belong to a class of magnetically bulk-doped topological insulators. The evolution of magnetic correlations from ferromagnetic to antiferromagnetic gives rise to topological phase transitions, where the paramagnetic topological insulator of Bi2Te3 turns into a band insulator with ferromagnetic-cluster glassy behavior around x∼0.025, and it further evolves to a topological insulator with valence-bond glassy behavior, which spans over the region from x∼0.03 up to x∼0.1. This phase diagram is verified by measuring magnetization, magnetotransport, and angle-resolved photoemission spectra with theoretical discussions.

Successful treatment of monomorphic primary central nervous system post-transplantation lymphoproliferative disorder 5 years after kidney transplantation

A 31-year-old man underwent living-related kidney transplantation in 2004 as a consequence of primary focal segmental glomerulosclerosis (FSGS). Four years after the transplantation, we confirmed nephrotic syndrome caused by recurrent FSGS. We performed plasmapheresis and low-density lipoprotein adsorption. We also combined steroid therapy with a reduction in the dose of tacrolimus and an increased dose of mycophenolate mofetil. The nephrotic syndrome improved dramatically with this combined therapeutic approach. However, 10 months after these treatments, he revisited our hospital because of altered consciousness. We detected multiple tumor masses in his brain that were ring enhanced on contrast magnetic resonance imaging. Consequently, we suspected primary central nervous system post-transplantation lymphoproliferative disorder (CNS-PTLD). We performed a craniotomy to biopsy the brain tumors. The biopsy specimen showed Epstein-Barr virus-associated diffuse large B-cell lymphoma. There is no definitive treatment for CNS-PTLD. Therefore, we treated the primary CNS-PTLD successfully with whole-brain radiation and discontinuation of immunosuppression therapy.

[Usefulness of serum procalcitonin measurement in the diagnosis of bacterial infection in patients with systemic autoimmune diseases]

Procalcitonin (PCT), a precursor for calcitonin, has been reported to be elevated in bacterial infection. However, its significance in the diagnosis of bacterial infection in patients with systemic autoimmune diseases, who have treatment with corticosteroid and immunosuppressive drug, is limited. To investigate the usefulness of serum procalcitonin measurement in the diagnosis of bacterial infection in patients with systemic autoimmune diseases, we analyzed 28 patients with systemic autoimmune diseases hospitalized because of fever and/or C-reactive protein (CRP) elevation. PCT was measured by the immunochromatography assay. Fourteen patients were considered having bacterial infections and the other 14 patients were considered having disease flare of their systemic autoimmune diseases. Serum CRP levels in the bacterial infection group was higher than that in the systemic autoimmune disease flare group; however, the difference did not reach statistical significance. The positive rate of serum PCT was significantly higher in the bacterial infection group (10/14, 71%) than that in the systemic autoimmune disease flare group (1/14, 7%), although there were 2 cases showing false positive PCT probably due to rheumatoid factor. This study suggested that PCT is useful in the diagnosis of bacterial infection in patients with systemic autoimmune diseases who are treated with corticosteroid and immunosuppressive drug.