Publications by authors named "Ryo Wakita"

17 Publications

  • Page 1 of 1

Differential Tissue Metabolic Signatures in IgG4-Related Ophthalmic Disease and Orbital Mucosa-Associated Lymphoid Tissue Lymphoma.

Invest Ophthalmol Vis Sci 2021 01;62(1):15

Department of Ophthalmology, Tokyo Medical University, Tokyo, Japan.

Purpose: To identify tissue metabolomic profiles in biopsy specimens with IgG4-related ophthalmic disease (IgG4-ROD) and mucosa-associated lymphoid tissue (MALT) lymphoma and investigate their potential implication in the disease pathogenesis and biomarkers.

Methods: We conducted a comprehensive analysis of the metabolomes and lipidomes of biopsy-proven IgG4-ROD (n = 22) and orbital MALT lymphoma (n = 21) specimens and matched adjacent microscopically normal adipose tissues using liquid chromatography time-of-flight mass spectrometry. The altered metabolomic profiles were visualized by heat map and principal component analysis. Metabolic pathway analysis was performed by Metabo Analyst 4.0 using differentially expressed metabolites. The diagnostic performance of the metabolic markers was evaluated using receiver operating characteristic curves. Machine learning algorithms were implemented by random forest using the R environment. Finally, an independent set of 18 IgG4-ROD and 17 orbital MALT lymphoma specimens were used to validate the identified biomarkers.

Results: The principal component analysis showed a significant difference of both IgG4-ROD and orbital MALT lymphoma for biopsy specimens and controls. Interestingly, lesions in IgG4-ROD were uniquely enriched in arachidonic metabolism, whereas those in orbital MALT lymphoma were enriched in tricarboxylic acid cycle metabolism. We identified spermine as the best discriminator between IgG4-ROD and orbital MALT lymphoma, and the area under the receiver operating characteristic curve of the spermine to discriminate between the two diseases was 0.89 (95% confidence interval, 0.803-0.984). A random forest model incorporating a panel of five metabolites showed a high area under the receiver operating characteristic curve value of 0.983 (95% confidence interval, 0.981-0.984). The results of validation revealed that four tissue metabolites: N1,N12-diacetylspermine, spermine, malate, and glycolate, had statistically significant differences between IgG4-ROD and orbital MALT lymphoma with receiver operating characteristic values from 0.708 to 0.863.

Conclusions: These data revealed the characteristic differences in metabolomic profiles between IgG4-ROD and orbital MALT lymphoma, which may be useful for developing new diagnostic biomarkers and elucidating the pathogenic mechanisms of these common orbital lymphoproliferative disorders.
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http://dx.doi.org/10.1167/iovs.62.1.15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7814356PMC
January 2021

Modified Low Power Mode Laser for the Treatment of Central Serous Chorioretinopathy.

Clin Ophthalmol 2020 30;14:4109-4113. Epub 2020 Nov 30.

Department of Ophthalmology, Tokyo Medical University, Ibaraki Medical Center, Inashiki, Ibaraki 3000395, Japan.

Purpose: Low power mode (LPM) can be used for subthreshold retinal laser treatment by simply adjusting the laser parameters. Herein, we report the use of a modified LPM laser treatment for four cases of central serous chorioretinopathy (CSCR).

Patients And Methods: We retrospectively reviewed the medical records of four patients (four eyes) with persistent CSCR who underwent modified LPM laser for leakage. The laser power was first titrated with a barely visible burn, and then treatment was applied using 33% laser energy by manually adjusting the laser power and duration.

Results: Serous retinal detachment completely resolved in all cases by 2 months after treatment. Autofluorescence images did not show any specific changes induced by laser burns.

Conclusion: A modified LPM laser may provide a feasible treatment for persistent CSCR.
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http://dx.doi.org/10.2147/OPTH.S284005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721272PMC
November 2020

Serum Metabolomic Profiling of Patients with Non-Infectious Uveitis.

J Clin Med 2020 Dec 6;9(12). Epub 2020 Dec 6.

Department of Ophthalmology, Tokyo Medical University, Tokyo 160-0023, Japan.

The activities of various metabolic pathways can influence the pathogeneses of autoimmune diseases, and intrinsic metabolites can potentially be used to diagnose diseases. However, the metabolomic analysis of patients with uveitis has not yet been conducted. Here, we profiled the serum metabolomes of patients with three major forms of uveitis (Behҫet's disease (BD), sarcoidosis, and Vogt-Koyanagi-Harada disease (VKH)) to identify potential biomarkers. This study included 19 BD, 20 sarcoidosis, and 15 VKH patients alongside 16 healthy control subjects. The metabolite concentrations in their sera were quantified using liquid chromatography with time-of-flight mass spectrometry. The discriminative abilities of quantified metabolites were evaluated by four comparisons: control vs. three diseases, and each disease vs. the other two diseases (such as sarcoidosis vs. BD + VKH). Among 78 quantified metabolites, 24 kinds of metabolites showed significant differences in these comparisons. Four multiple logistic regression models were developed and validated. The area under the receiver operating characteristic (ROC) curve (AUC) in the model to discriminate disease groups from control was 0.72. The AUC of the other models to discriminate sarcoidosis, BD, and VKH from the other two diseases were 0.84, 0.83, and 0.73, respectively. This study provides potential diagnostic abilities of sarcoidosis, BD, and VKH using routinely available serum samples that can be collected with minimal invasiveness.
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http://dx.doi.org/10.3390/jcm9123955DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7762156PMC
December 2020

Interfacial interaction of anesthetic lidocaine and mesoporous silica nanoparticles in aqueous solutions and its release properties.

J Mater Chem B 2019 11 22;7(44):7026-7032. Epub 2019 Oct 22.

Tokyo Medical and Dental University, School of Medical and Dental Sciences, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.

Lidocaine has been used as a local anesthetic by injection. The controlled release of lidocaine loaded into nanospheres is necessary to reduce the onset time of the anesthetic effect or increase the anesthetic analgesia duration. In this study, mesoporous silica nanoparticles (MSNs) with a large specific surface area were prepared by a sol-gel method, and the interfacial interaction between MSNs and lidocaine positively charged in aqueous solutions at different concentrations was investigated by adsorption tests, Fourier-transformed infrared spectroscopy, thermogravimetry-differential thermal analysis, and Brunauer-Emmett-Teller (BET) measurements. The electrostatic interaction between Si-OH on MSNs and lidocaine-NH was of importance for the adsorption phenomenon in aqueous solutions, indicating the monolayer adsorption of lidocaine. BET measurements also supported the decrease of pore volumes, and the hysteresis loop of the isotherm curve was not closed since the condensation of lidocaine in the mesopores formed micropores of less than 1.5 nm in size. The release profiles in phosphate buffered saline containing calcium and magnesium ions showed a rapid and higher release of lidocaine compared with that in phosphate buffered saline without divalent cations. The released lidocaine concentrations were sufficient for the expression of the anesthetic effect in dental anesthesia.
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http://dx.doi.org/10.1039/c9tb01999eDOI Listing
November 2019

Effects of Zoledronate on Local and Systemic Production of IL-1β, IL-18, and TNF-α in Mice and Augmentation by Lipopolysaccharide.

Biol Pharm Bull 2019 ;42(6):929-936

Division of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Tohoku University.

Bisphosphonates (BPs) containing nitrogen (N-BPs) exhibit far stronger anti-bone-resorptive effects than non-N-BPs. However, repeated administration of N-BPs causes osteonecrosis selectively in jawbones. As BPs accumulate in large amounts within inflamed bones, any N-BP released from the pool accumulated within jawbones might directly act on cells in the surrounding soft-tissues and induce inflammation or necrosis. Here, we examined the local and systemic effects of zoledronate (the most potent N-BP with the highest incidence of jawbone-necrosis) on inflammatory cytokines in mice. Locally within ear-pinnas: (i) zoledronate induced long-lasting accumulation of interleuikin-1β (IL-1β) and IL-18, but not tumor necrosis factor-α (TNF-α), (ii) zoledronate and lipopolysaccharide (LPS, a cell-wall component of Gram-negative bacteria) mutually augmented the productions of IL-1β, IL-18, and TNF-α, and (iii) oxidronate (a toxic non-N-BP) by itself produced not only IL-1β and IL-18, but also TNF-α. In systemic experiments using intraperitoneal injection of zoledronate and/or LPS, (i) zoledronate by itself increased none of the above cytokines in serum, and (ii) in mice pretreated (3 d before) with zoledronate, the LPS-induced increases in serum IL-1β and IL-18 were greatly augmented with a delayed slight TNF-α augmentation. These results, together with previous ones, suggest that (a) pro-IL-1β and pro-IL-18 accumulate within cells in soft-tissues exposed to N-BPs, and infection may augment not only their production, but also the release of their mature forms, (b) IL-1β and IL-18 (possibly together with TNF-α) may play important roles in N-BP-induced inflammation and/or necrosis, and (c) mechanisms underlying the cytotoxic effects of BPs may differ between N-BPs and non-N-BPs.
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http://dx.doi.org/10.1248/bpb.b18-00923DOI Listing
November 2019

Methemoglobinemia should be suspected when oxygen saturation apparently decreases after prilocaine infiltration during intravenous sedation.

Clin Case Rep 2018 Jun 17;6(6):1077-1081. Epub 2018 Apr 17.

Section of Anesthesiology and Clinical Physiology Division of Oral Health Sciences Department of Oral Restitution Graduate School Tokyo Medical and Dental University Tokyo Japan.

During intravenous sedation, a decrease in SpO2 is usually the result of respiratory failure. However, we experienced a case with SpO2 decrease that was caused by methemoglobinemia in prilocaine infiltration anesthesia during sedation. This indicates that methemoglobinemia should be considered if low SpO2 is sustained unrelated to sedation level.
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http://dx.doi.org/10.1002/ccr3.1522DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5986061PMC
June 2018

Differential regulations of vestibulo-ocular reflex and optokinetic response by β- and α2-adrenergic receptors in the cerebellar flocculus.

Sci Rep 2017 06 21;7(1):3944. Epub 2017 Jun 21.

Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.

Norepinephrine modulates synaptic plasticity in various brain regions and is implicated in memory formation, consolidation and retrieval. The cerebellum is involved in motor learning, and adaptations of the vestibulo-ocular reflex (VOR) and optokinetic response (OKR) have been studied as models of cerebellum-dependent motor learning. Previous studies showed the involvement of adrenergic systems in the regulation of VOR, OKR and cerebellar synaptic functions. Here, we show differential contributions of β- and α2-adrenergic receptors in the mouse cerebellar flocculus to VOR and OKR control. Effects of application of β- or α2-adrenergic agonist or antagonist into the flocculus suggest that the β-adrenergic receptor activity maintains the VOR gain at high levels and contributes to adaptation of OKR, and that α2-adrenergic receptor counteracts the β-receptor activity in VOR and OKR control. We also examined effects of norepinephrine application, and the results suggest that norepinephrine regulates VOR and OKR through β-adrenergic receptor at low concentrations and through α2-receptor at high concentrations.
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http://dx.doi.org/10.1038/s41598-017-04273-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5479797PMC
June 2017

Drug delivery and transmission of lidocaine using iontophoresis in combination with direct and alternating currents.

J Med Dent Sci 2016 ;63(4):71-77

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.

The present study investigates how effectively lidocaine ions are transported across a cellophane membrane through the application of either a direct current (DC) or alternating current (AC). The cellophane membrane was set on a parallelplate- type acrylic cell with platinum electrodes at both ends, filled with a donor cell of a 1 % aqueous solution of lidocaine and a receptor cell with distilled water. Lidocaine concentrations were measured for 60 min while the following voltages were applied, with changes every 10 min: 3 V DC and 7.5 V sine wave AC; frequency at 1 kHz. As a result, lidocaine concentrations in the receptor cell increased in a time-dependent manner. Significant increases in lidocaine concentrations were observed in groups where the voltage combination consisted of DC 30 min/AC 30 min, DC 50 min/AC 10 min, DC 60 min and AC 10 min/DC 50 min, compared with the passive diffusion group or in groups where voltage application was performed for 20, 30 , 40, 50 and 60 min. Significant increases were also observed in groups where the voltage combination consisted of A C 6 0 min, D C 10 min/AC 5 0 min, AC 3 0 min/ DC 30 min and AC 50 min/DC 10 min, compared with the passive diffusion group or in groups where voltage application was performed for 40, 50 and 60 min. These results suggest that lidocaine was delivered more rapidly with DC than with AC, and that its ions are transported faster when voltage is switched from DC to AC than from AC to DC, which is presumably due to the contribution of electrorepulsion by DC voltage application and the vibration energy infiltration mechanism owning to AC. Iontophoresis in combination with DC and AC was found to enable highly efficient drug delivery that shares the benefits of both forms of current application.
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http://dx.doi.org/10.11480/jmds.630402DOI Listing
March 2017

Evaluation of calcium alginate gel as electrode material for alternating current iontophoresis of lidocaine using excised rat skin.

J Med Dent Sci 2014 Jun 27;61(2):41-8. Epub 2014 Jun 27.

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan.

Iontophoresis (IOP) is a noninvasive method of delivering medication transcutaneously through the skin. The electrodes used in this method should tightly fit to rough and irregular surfaces and be biologically safe, easy to handle and prepare, and cost-effective. To satisfy these requirements, calcium alginate gel can be a candidate electrode for IOP. Using calcium alginate gel electrodes, we examined whether lidocaine can be effectively transported across an excised rat skin by squarewave alternating current (AC) application. A squarewave AC with either a 70% or 80% duty cycle was continuously applied to 0.5% calcium alginate gel electrodes containing 10% lidocaine at 10 V and 1 kHz for 60 min. Lidocaine concentration was measured using a spectrophotometer and the temperature of the gel was determined. The lidocaine concentrations for AC-IOP at the 70% and 80% duty cycles were significantly higher than that without AC-IOP. Furthermore, the group with the 80% duty cycle showed higher lidocaine concentrations than the group with the 70% duty cycle. The temperatures of all the groups were lower than 28 °C throughout the procedure. In conclusion, the calcium alginate gel can be used as a possible matrix for IOP electrodes.
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http://dx.doi.org/10.11480/610201DOI Listing
June 2014

Efficacy of lidocaine lontophoresis using either alternating or direct current in hairless rats.

J Med Dent Sci 2013 Sep 30;60(3):63-71. Epub 2013 Sep 30.

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University.

The aim of this study was to determine transport of lidocaine ions through a hairless rat skin in vivo and to compare the efficacy of alternating current (AC) with that of direct current (DC) iontophoresis (IOP). We measured the concentration of lidocaine transported through a cellophane membrane or a hairless rat dorsal skin applying either AC-IOP or DC-IOP. The results revealed that lidocaine concentration increased in a time-dependent manner in vitro in both DC-IOP and AC-IOP. However, the in vivo study showed different tendencies in lidocaine concentration. In the DCIOP group, lidocaine concentration reached its maximum 20 min after current application and then decreased rapidly; the AC-IOP group showed an increase in lidocaine concentration in a time-dependent manner. There were no side effects such as electrical burns in the rats. In conclusion, AC can be applied for long periods and DC for short periods, or their application time can be appropriately scheduled. Our study also suggests the mechanism by which voltage waveforms affect the skin when applied by IOP. In the future, these findings will be a solid foundation for developing various kinds of medical equipment such as scheduled drug delivery system that can easily deliver various types of drug.
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September 2013

Active components of ginger potentiate β-agonist-induced relaxation of airway smooth muscle by modulating cytoskeletal regulatory proteins.

Am J Respir Cell Mol Biol 2014 Jan;50(1):115-24

1 Department of Anesthesiology, Columbia University, New York, New York; and.

β-Agonists are the first-line therapy to alleviate asthma symptoms by acutely relaxing the airway. Purified components of ginger relax airway smooth muscle (ASM), but the mechanisms are unclear. By elucidating these mechanisms, we can explore the use of phytotherapeutics in combination with traditional asthma therapies. The objectives of this study were to: (1) determine if 6-gingerol, 8-gingerol, or 6-shogaol potentiate β-agonist-induced ASM relaxation; and (2) define the mechanism(s) of action responsible for this potentiation. Human ASM was contracted in organ baths. Tissues were relaxed dose dependently with β-agonist, isoproterenol, in the presence of vehicle, 6-gingerol, 8-gingerol, or 6-shogaol (100 μM). Primary human ASM cells were used for cellular experiments. Purified phosphodiesterase (PDE) 4D or phospholipase C β enzyme was used to assess inhibitory activity of ginger components using fluorescent assays. A G-LISA assay was used to determine the effects of ginger constituents on Ras homolog gene family member A activation. Significant potentiation of isoproterenol-induced relaxation was observed with each of the ginger constituents. 6-Shogaol showed the largest shift in isoproterenol half-maximal effective concentration. 6-Gingerol, 8-gingerol, or 6-shogaol significantly inhibited PDE4D, whereas 8-gingerol and 6-shogaol also inhibited phospholipase C β activity. 6-Shogaol alone inhibited Ras homolog gene family member A activation. In human ASM cells, these constituents decreased phosphorylation of 17-kD protein kinase C-potentiated inhibitory protein of type 1 protein phosphatase and 8-gingerol decreased myosin light chain phosphorylation. Isolated components of ginger potentiate β-agonist-induced relaxation in human ASM. This potentiation involves PDE4D inhibition and cytoskeletal regulatory proteins. Together with β-agonists, 6-gingerol, 8-gingerol, or 6-shogaol may augment existing asthma therapy, resulting in relief of symptoms through complementary intracellular pathways.
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http://dx.doi.org/10.1165/rcmb.2013-0133OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3930933PMC
January 2014

A comparison of dexmedetomidine sedation with and without midazolam for dental implant surgery.

Anesth Prog 2012 ;59(2):62-8

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.

Dexmedetomidine (DEX) has a minimal respiratory depressive effect, which is beneficial for dentistry; however, it has the disadvantage of permitting an intraoperative arousal response such that the patient appears to be suddenly no longer sedated, and it has a variable amnestic effect. Since midazolam (MDZ) in an appropriate dose has a profound amnesic effect, we investigated whether additional MDZ compensates for the disadvantage of DEX and enables a better quality of sedation. Forty-three subjects were randomly divided into 4 groups. In group 1, MDZ (0.02 mg/kg) was administered intravenously, followed by a dose of 0.01 mg/kg every 45 minutes. After the first dose of MDZ, preloading with DEX (2 µg/kg/h for 10 minutes) was started and maintained with a dosage of 0.5 µg/kg/h. In group 2, MDZ was infused in the same manner as in group 1, followed by preloading with DEX (1 µg/kg/h for 10 minutes) and maintenance (0.3 µg/kg/h). In group 3, MDZ was infused 0.03 mg/kg, and a dose of 0.01 mg/kg was given every 30 minutes; DEX was administered at the same as in group 2. In group 4, DEX was infused using the same method as in group 1 without MDZ. The sedation levels, amnesia, and patient satisfaction were also investigated. Group 2 had a lower sedation level and a poor evaluation during the first half of the operation. Group 4 did not exhibit an amnesic effect at the beginning of the operation. An evaluation of the degree of patient satisfaction did not reveal any differences among the groups. Optimal sedation was achieved through the combined use of MDZ (0.02 mg/kg with the addition of 0.01 mg/kg every 45 minutes) and DEX (2 µg/kg/h for 10 minutes followed by 0.5 µg/kg/h).
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http://dx.doi.org/10.2344/11-11.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3403583PMC
September 2012

In vitro evaluation of calcium alginate gels as matrix for iontophoresis electrodes.

J Med Dent Sci 2012 Mar 13;59(1):9-16. Epub 2012 Mar 13.

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, JAPAN.

Calcium alginate gel has some unique properties, such as the capability to keep the drugs, bioadhesiveness, safety, and low cost. The purpose of this study is to determine whether calcium alginate gel can be used as a matrix of electrodes for iontophoresis (IOP). We measured the concentration of lidocaine transported from calcium alginate gels with various concentrations of alginic acid using an in vitro experimental cell with square-wave alternating current (AC) application. Temperature and pH changes were also determined during AC-IOP. The results revealed that lidocaine was released from calcium alginate gels at concentrations nearly 1.71-fold larger at 5 V, 60 min after AC application than in the case of passive diffusion. Lidocaine transport depended on the alginic acid concentration in the gels. Although there were slight increases in temperature and pH, chemical and thermal burns were not severe enough to be a concern. In conclusion, the calcium alginate gel can be used as a possible matrix for IOP electrodes.
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March 2012

The relation between the duty cycle and anesthetic effect in lidocaine iontophoresis using alternating current.

Pain Pract 2011 May-Jun;11(3):261-6. Epub 2010 Sep 20.

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.

We assessed the effect of the duty cycle on the anesthetic effect during lidocaine alternating current (AC) iontophoresis. A solution of 2% lidocaine was delivered to the medial antecubital skin for 20 minutes using AC iontophoresis with a duty cycle of 60%, 70%, or 80%. The von Frey test was then performed to evaluate the anesthetic effect. In the groups treated with a duty cycle of 80% or 70% the touch thresholds (TT) were significantly elevated from 0 minutes to 30 minutes and from 0 minutes to 20 minutes. TT were significantly elevated at 0 minutes in the group treated with a 60% duty cycle. The anesthetic effect was significantly enhanced in a duty cycle-dependent manner.
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http://dx.doi.org/10.1111/j.1533-2500.2010.00418.xDOI Listing
August 2011

The relation between epinephrine concentration and the anesthetic effect of lidocaine iontophoresis.

Pain Pract 2009 Mar-Apr;9(2):115-21. Epub 2008 Nov 5.

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.

We assessed the effect of epinephrine at various concentrations on the anesthetic effect during lidocaine iontophoresis. A solution of 2% lidocaine with epinephrine in concentration of 1:80,000, 1:160,000, 1:320,000, 2% lidocaine plain and normal saline control was delivered to the medial antecubital skin for 10 minutes by iontophoresis with 1.0 mA of direct current. The pinprick test and the von Frey test were conducted to evaluate anesthetic effect. Pricking pain using visual analogue scale was significantly lower throughout the entire experiment compared with the baseline values and lasted for 60 minutes in groups with 1:80,000 and 1:160,000 epinephrine. The pressure pain thresholds (PPT) and the touch thresholds (TT) were significantly elevated in groups with 1:80,000 and 1:160,000 epinephrine compared with the baseline values. No significant elevations in the PPT and TT values were observed in the other groups. The present study revealed that the anesthetic effect was significantly enhanced in an epinephrine dose-related manner and the anesthetic effect of 2% lidocaine with 1:160,000 epinephrine was equivalent to the same anesthetic with 1:80,000 epinephrine.
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http://dx.doi.org/10.1111/j.1533-2500.2008.00252.xDOI Listing
May 2009

Occurrence of intermittent Wolff-Parkinson-White syndrome during intravenous sedation.

J Clin Anesth 2008 Mar;20(2):146-9

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan.

Patients with intermittent Wolff-Parkinson-White (WPW) syndrome, defined as intermittent loss of the delta waves, can show occasional conduction through the accessory pathway. WPW syndrome often causes paroxysmal supraventricular tachycardia or atrial fibrillation. However, it may be difficult to identify the abnormalities preoperatively because of their only intermittent occurrence. We report a case in which exogenously administered epinephrine and an autonomic imbalance may have precipitated the abrupt occurrence and disappearance of the delta waves.
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http://dx.doi.org/10.1016/j.jclinane.2007.06.025DOI Listing
March 2008

Vasovagal syncope with asystole associated with intravenous access.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006 Dec 2;102(6):e28-32. Epub 2006 Oct 2.

Section of Anesthesiology and Clinical Physiology, Department of Oral Restitution, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.

Two cases of vasovagal syncope (VVS) during venous access are reported. Both patients had a history of fainting episodes and experienced bradycardia with asystole, hypotension, and fainting. Pain and phobic stress during venous access triggered an increase in parasympathetic tone, resulting in bradycardia with asystole and hypotension in both cases. Hypotension and bradycardia likely caused cerebral hypoperfusion, leading to fainting. The intense parasympathetic tone triggered by somatic or emotional stress was likely responsible for directly depressing the sinus node, leading to asystole and bradycardia. Bradycardia with asystole progressing to syncope is a potentially fatal dysrhythmia in patients with cardiovascular disease or older patients with decreased cardiac function. Appropriate treatment for VVS includes the administration of intravenous fluids, vagolytics, ephedrine, and the rapid use of the Trendelenburg position. Intravenous fluids and atropine were used to treat the present patients.
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http://dx.doi.org/10.1016/j.tripleo.2006.06.005DOI Listing
December 2006
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