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Biomedical subjects

Yoshiaki Hara

Publications and source records attributed to Yoshiaki Hara.

At least 19 recordsLinked to original sources
PubMed2006

Diversity of secondary endosymbiont-derived actin-coding genes in cryptomonads and their evolutionary implications.

In the secondary endosymbiotic organisms of cryptomonads, the symbiont actin genes have been found together with the host one. To examine whether they are commonly conserved and where they are encoded, host and symbiont actin genes from Pyrenomonas helgolandii were isolated, and their specific and homologous regions were digoxigenin (DIG) labeled separately. Using these probes, Southern hybridization was performed on 13 species of cryptomonads. They were divided into three groups: (1) both host and symbiont actin gene signals were detected, (2) only the host actin gene signal was detected, and (3) host and unknown actin signals were detected. The phylogenetic analysis of these actin gene sequences indicated that the evolutionary rates of the symbiont actin genes were accelerated more than those of the hosts. The unknown actin signals were recognized as the highly diverged symbiont actin genes. One of the diverged symbiont actin sequences from Guillardia theta is presumed to be as a pseudogene or to its precursor. Southern hybridizations based on the samples divided by pulsed-field gel electrophoresis showed that all actin genes were encoded by the host nuclei. These results possibly represent the evolutionary fate of the symbiont actin gene in cryptomonads, which was firstly transferred from the symbiont nucleus or nucleomorph, to the host nucleus and became a pseudogene and then finally disappeared there.

Actins↗
PubMed2006

Anergic lymphocytes generated by blocking CD28 and ICOS pathways in vitro prolong rat cardiac graft survival.

Regulatory cells may play a pivotal role in inducing and maintaining transplantation tolerance. We investigated the mechanism of anergic lymphocytes with regulatory cell potential generated in vitro by ICOS and CD 28 co-stimulatory blockades as a source of cellular therapy for treating allograft rejection. Anergic lymphocytes were generated by a mixed lymphocyte reaction consisting of DA splenocytes as the stimulator and Lewis splenocytes as the responder in the presence of anti-ICOS mAb and rCTLA-4I g. Immunoregulatory effects of these lymphocytes were evaluated by secondary MLR and using other various stimulations. DA heart was transplanted into 7.5 Gy-irradiated Lewis rat after intravenous administration of these cells and/or Lewis spleen lymphocytes. We observed that these lymphocytes were not only anergic to alloantigen and polyclonal stimulations but also exhibited regulative activity to inhibit the alloreactive T-cell response. Our adoptive transfer studies revealed that irradiated recipients that received both anergic lymphocytes and naIve Lewis lymphocytes had significantly prolonged DA cardiac graft survival (mean 17.5 days) compared with a group that received Lewis lymphocytes alone (mean 10.8 days). Furthermore, some of the recipients accepted the graft indefinitely after receiving anergic lymphocytes alone (>100 days). These results demonstrated that anergic lymphocytes with regulatory activities can be generated through blocking co-stimulatory signals, CD 28 and ICOS, simultaneously in vitro, and may advance a new immunomodulatory strategy for preventing allorejection in organ transplantation.

Abatacept↗
PubMed2006

Management of major portosystemic shunting in small-for-size adult living-related donor liver transplantation with a left-sided graft liver.

PURPOSE: We investigated the mechanisms of small-for-size graft syndrome by time-lag ligation, a novel approach to treating major portosystemic shunts in small-for-size adult living-related donor liver transplantation (LRDLT) using left-sided graft liver. METHODS: Five patients with end-stage liver failure and major splenorenal shunting underwent LRDLT using left lobe grafts. The average graft volume to recipient body weight (GV/RBW) ratio was 0.68 +/- 0.14. Two patients underwent time-lag ligation of their splenorenal (SR) shunts on postoperative days (PODs) 8 and 14, respectively. The shunts of the other three patients were untreated. RESULTS: The portal pressures in the first patient who underwent time-lag ligation rose above 300 mmH(2)O and remained there for 2 weeks. Thus, we ligated the SR shunt in the second patient on POD 14, resulting in an increase from 177 mmH(2)O to 258 mmH(2)O, but it decreased again thereafter. In the other three patients, the SR shunt was not ligated because portal blood flow volumes remained sufficient. Total bilirubin levels in the first time-lag ligation patient rose to 16 mg/dl, paralleling the rise in portal pressures. Although they increased after ligation in the second patient, they did not exceed 10 mg/dl. CONCLUSIONS: We recommend time-lag ligation if portal venous blood flow decreases in the early post-transplant period, but not until at least 2 weeks after transplantation. If the portal venous blood flow does not decrease, early postoperative ligation is unnecessary. If there are no major portosystemic shunts, making a portosystemic shunt might decompress excessive portal hypertension. With donor safety priority in LRDLT, novel approaches must be developed to enable the use of smaller donor grafts. We describe a potential means of using left lobe grafts in adult LRDLT.

Age Factors↗
PubMed2006

Frequency doubling technology perimetry after clear and yellow intraocular lens implantation.

PURPOSE: To evaluate the effect of intraocular lens (IOL) color on frequency doubling technology (FDT). DESIGN: Randomized clinical trial. METHODS: For 26 eyes of 26 patients, FDT perimetry (24-2-threshold test) was measured three months after cataract surgery. An acrylic IOL was randomly selected from clear (VA60BB, HOYA) and yellow-tinted lenses (YA60BB, HOYA), which only differed by color. As a control, a further 14 cataractous eyes with visual acuity > or =20/30 were examined. We analyzed mean deviation (MD) and pattern standard deviation (PSD) among the three groups. RESULTS: After cataract surgery, MD significantly improved (Fisher protected least significant difference (PLSD): P < .05), but PSD did not change (analysis of variance (ANOVA): P = .94) compared with control values. There was no significant difference between the two IOLs for either MD (Mann-Whitney test; P = .15) or PSD (Mann-Whitney test; P = .84). CONCLUSIONS: When interpreting the results of FDT, the effect of cataract should be considered but that of IOL color does not need consideration.

Color↗
PubMed2006

Effect of total higher-order aberrations on accommodation in pseudophakic eyes.

PURPOSE: To analyze the effect of total higher-order aberrations (HOAs) on the range of accommodation in pseudophakic eyes and the size of near-vision optotypes. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: The study comprised 30 patients (44 eyes) who were diagnosed with cataract at Nara University of Medical Science Hospital and Municipal Oyodo Hospital. Inclusion criteria included no other eye disorder and a best corrected distance acuity of 20/20 or better 1 month after cataract surgery. All patients had small-incision phacoemulsification followed by in-the-bag implantation of a monofocal intraocular lens (SA60AT, Alcon). All incisions were self-sealing. Accommodation in pseudophakic eyes was measured by the lens-loading method in an examination room under constant illumination. Ocular HOAs were measured using the KR-9000PW Hartmann-Shack wavefront analyzer (Topcon). RESULTS: The mean patient age was 75.8 years +/- 5.4 (SD) (range 64 to 83 years). The Pearson correlation coefficient (r) showed a significant positive correlation between the range of accommodation and Z7 (vertical coma) for a 4.0 mm pupil using the 1.0 near-vision optotype. There was a significant negative correlation between the range of accommodation and Z12 (spherical aberration) for a 4.0 mm pupil using the 1.0 near-vision optotype (r = .311, P = .040 for Z7;r = -.365, P = .015 for Z12). No other parameter was significantly correlated with the range of accommodation. CONCLUSIONS: Measurement of accommodation in pseudophakic eyes by the lens-loading method using the 1.0 near-vision optotype showed that eyes with larger vertical coma aberrations achieved a larger range of accommodation. In contrast, eyes with larger spherical aberrations had smaller amounts of accommodation. The size of the near-vision optotype may affect accommodation analysis in pseudophakic eyes.

Accommodation, Ocular↗
PubMed2006

Pattern-reversal visual evoked potentials in patients with human T-lymphotropic virus type 1 uveitis.

PURPOSE: The purpose of this study was to evaluate the possible injury in the optic pathway by measuring P100 peak latency of pattern-reversal visual evoked potentials (PVEPs) in patients with human T-lymphotropic virus type 1 uveitis (HU). METHODS: The P100 peak latency of PVEP was measured during the period without macular abnormalities observed by fluorescein angiography in 23 patients (46 eyes) with HU and 24 patients (48 eyes) with Vogt-Koyanagi-Harada disease (VKH) with a corrected visual acuity of 20/25 or more. To determine the normal upper limit of P100 peak latency, PVEPs were measured in 31 normal subjects (31 eyes). In addition, in the HU patients, the serum anti-HTLV-1 antibody titer was measured by particle agglutination assay within 3 months of PVEP recording, and the period of HU was retrospectively surveyed. RESULTS: Delayed latency was observed in 4 (7 eyes) of the 23 patients (46 eyes) with HU but none of the 24 patients (48 eyes) with VKH. All four patients with delayed latency showed a serum anti-HTLV-1 antibody titer of more than x4000. The HU period in the HU patients was 0.2-14.0 years, and the HU periods in the four patients with delayed latency were 0.8, 2.7, 4.2, and 14.0 years, respectively. CONCLUSIONS: We measured pattern-reversal visual evoked potentials and observed delayed P100 peak latency in 7 of the 46 eyes in 4 (17.4%) of the 23 HU patients. This suggests injury in the optic pathway including the optic nerve by HTLV-1 in some patients with HU. In the future, consideration should also be given to the possible development of optic neuropathy due to HTLV-1.

Adolescent↗
PubMed2006

Traumatic optic neuropathy caused by blunt injury to the inferior orbital rim.

A 48-year-old woman was struck on the right inferior orbital rim by a gardening device and immediately developed complete visual loss in the right eye. Clinical and imaging evaluations failed to disclose any damage to the globe or optic nerve or to their nearby soft tissues and bones. Within months, ipsilateral optic disc pallor, a nerve fiber bundle visual field defect, and a persistently subnormal visual acuity developed. We attribute the visual loss to indirect optic nerve injury. To our knowledge, blunt injury to the inferior orbital rim has not been reported as a cause of this phenomenon.

Eye Injuries↗
PubMed2006

Effect of static visual acuity on dynamic visual acuity: a pilot study.

The aim of this pilot study was to evaluate whether dynamic visual acuity changes with or without refractive correction. 42 healthy enrolled subjects with normal vision were divided into two age-matched groups. In Group A, dynamic visual acuity was measured first with the refractive error fully corrected and then without. In Group B, dynamic visual acuity measurements were taken in the reverse order of that performed by Group A. The measurements were binocularly performed five times using free-head viewing after dynamic visual acuity values were stable. Significant changes in dynamic visual acuity (static visual acuity 20/20 vs 12/20) were observed in both Group A (171.6 +/- 36.0 deg./sec. vs 151.8 +/- 39.6 deg./sec., Wilcoxon test, p < .001) and Group B (169.8 +/- 30.0 deg./sec. vs 151.2 +/- 36.0 deg./sec., Wilcoxon test, p < .001). The interaction was significant (F1.20 = 8.12, p = .009). These results indicated that refractive correction affected dynamic visual acuity.

Adult↗
PubMed2006

Effectiveness of a "doctor-helicopter" system in Japan.

BACKGROUND: In Japan, helicopters have rarely been used for emergency medical services. The use of helicopters not only ensures rapid evacuation but may also serve to provide emergency management to patients with life-threatening injuries in the prehospital setting. OBJECTIVES: To evaluate a Japanese helicopter-based emergency medical system including an onboard physician, particularly in terms of probability of survival. METHODS: We conducted a retrospective review of trauma victims, and calculated two estimates of PS--at the scene and on arrival at the emergency department--based on patient age, Injury Severity Score, and Revised Trauma Score. RESULTS: We identified trauma victims who had an ISS above 15 and were transported from the scene by helicopter. Excluding cardiopulmonary arrest at the scene, 151 cases were studied. Thirty-two patients had hemodynamic instability with systolic blood pressures below 90 mmHg, caused by hemorrhagic shock (29 cases) or obstructive shock (3 cases). Their PS values were 0.56 +/- 0.38 in the prehospital setting and 0.65 +/- 0.38 on arrival at the ED, representing a significant difference (P = 0.0003). Twenty-four of these patients survived, reflecting successful resuscitation during prehospital and ED management. CONCLUSIONS: A doctor-helicopter system was shown to improve probability of survival for life-threatening trauma in the Japanese emergency medical system.

Adolescent↗
PubMed2006

[Clinical application of multifocal visual evoked potentials in children with epilepsy caused by intracranial disease].

PURPOSE: We investigated whether visual field defects could be objectively evaluated using multifocal visual evoked potential(m-VEP) in two children with epilepsy caused by intracranial disease in whom it was difficult to measure the visual field. METHODS: To determine normal waves in m-VEP, recording was performed using a visual evoked response imaging system(VERIS)Junior Science program (Mayo, Aichi, Japan) in 20 healthy children (20 eyes); peak latency and amplitude were used for assessment. In the two children with epilepsy, m-VEPs were recorded, and compared with the results of static perimetry or the lesions observed by Magnetic Resonance Imaging (MRI). RESULTS: In the 20 healthy children, there was no significant difference in the peak latency or amplitude among 4 quadrants by one-way analysis of variance. m-VEP in the children with epilepsy showed abnormal waves, corresponding to the visual field defects in the static perimetry or the lesions observed by MRI. CONCLUSIONS: Objective evaluation of visual field defects using m-VEP may be useful in children with epilepsy caused by intracranial disease in whom kinetic/static perimetry as a subjective examination is difficult.

Brain Diseases↗
PubMed2006

[Objective evaluation of the visual field defects in a patient with cerebral infarction using multifocal VEPs].

PURPOSE: We investigated whether visual field defects can be objectively evaluated using multifocal visual evoked potentials (mVEP) in a patient with cerebral infarction in whom it is difficult to measure the visual field. METHODS: To determine normal waves in mVEP recording was performed using a VERIS Junior Science (Mayo, Aichi, Japan) in 20 healthy subjects (20 eyes), peak latency and amplitude were used for assessment. In a patient with cerebral infarction, mVEP were recorded, and compared with the lesion observed by computed tomography. RESULTS: In 20 healthy subjects, the waveforms in the nasal and temporal quadrants were very similar but the waveforms in the superior and inferior quadrants were mirror images. The mVEP in patient with cerebral infarction showed abnormal waves, corresponding to the visual field defects in the lesion observed by computed tomography. CONCLUSIONS: Objective evaluation of visual field defects using mVEP may be useful in patients with cerebral infarction in whom kinetic/static perimetry as a subjective examination is difficult.

Aged↗
PubMed2005

Relationship between the retinal thickness of the macula and the difference in axial length.

PURPOSE: The purpose of this study was to evaluate the relationship between the retinal thickness of the macula and the difference in axial length with A-scan ultrasonography (UD-6000) and partial coherence interferometry (IOLMaster). METHODS: In 38 eyes of 26 patients with macular edema (ME), we measured axial length using both instruments and the retinal thickness of the macula using optical coherence tomography (OCT). To compare the difference in axial length between both methods, the Wilcoxon signed-ranks test was used. In addition, the relationship between macula thickness and axial length difference was analyzed by Spearman's correlation coefficient. RESULTS: There was a significant difference between axial-length measurements (p<0.001). In addition, the retinal thickness of the macula and the difference in axial-length measurements were positively correlated (correlation coefficient = 0.55, p=0.003). CONCLUSIONS: The difference in axial length obtained by both methods was considered to be the difference in optical and acoustic reflection site. This study may suggest that IOLMaster is sufficient for measuring axial length in eyes with macular edema and reducing postoperative refractive errors.

Biometry↗
PubMed2005

Photoreceptor cells from mouse ES cells by co-culture with chick embryonic retina.

Degeneration of photoreceptors is a consistent and common endpoint in retinal diseases. Herein, we report the efficient induction of photoreceptor-like cells from mouse embryonic stem (ES) cells using chick embryonic retina tissue. Undifferentiated mouse ES cells were initially cultured in a preferential condition into a neural lineage, and ES cells were then co-cultured with chick embryonic day 6 (E6) retina tissues. After a 10-day co-culture, approximately 20% of the mouse ES derivatives became immuno-positive for rhodopsin. RT-PCR analysis demonstrated expression of the transcription factor crx and a distinct increase of rod photoreceptor-specific markers, IRBP and recoverin, after the start of the co-culture. These results indicate that co-culture of ES cells with chick embryonic retina tissue is a useful and efficient method for the induction of photoreceptor-like cells.

Animals↗
PubMed2005

Inhibition of allogeneic T-cell responses by dendritic cells expressing transduced indoleamine 2,3-dioxygenase.

BACKGROUND: Indoleamine 2,3-dioxygenase (IDO) is an enzyme involved in the catabolism of tryptophan and has been shown to prevent rejection of the fetus during pregnancy by inhibiting alloreactive T cells. METHODS: In this study we investigated dendritic cells (DCs) that are transfected with IDO cDNA in the inhibition of T-cell proliferation after antigen-specific interaction. XS106 DCs, derived from A/J mice (H-2k), were transduced with IDO with a gene-delivery system using a recombinant adenoviral vector. RESULTS: Western blotting and immune staining revealed IDO expression in XS106 DCs transduced with IDO (XS106-IDO DCs), and its catabolic effect was confirmed by an increase in kynurenine concentration. Fluorescence-activated cell sorting revealed that XS106-IDO DCs were not changeable for Ia, CD80, and CD86 expression. After XS106-IDO DCs were co-cultured with C57BL/6 allogeneic splenic T cells, the proliferation of the T cell was significantly inhibited. The co-cultured T cells with XS106-IDO DCs exhibited cell-cycle arrest. Furthermore, injection of XS160-IDO DCs into the footpads of C57BL/6 (H-2b) mice demonstrated a reduced T-cell response against allo-antigen. CONCLUSIONS: These results suggest that overexpression of IDO in the DCs effectively inhibited T-cell proliferation, and may expand a new immunomodulatory strategy for the prevention of allo-rejection of organ transplantation.

Adenoviridae↗
PubMed2005

Evaluation of apparent ectasia of the posterior surface of the cornea after keratorefractive surgery.

PURPOSE: To calculate the apparent posterior corneal changes after keratorefractive surgery and reevaluate corneal ectasia displayed by Orbscan (Orbtek). SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: Postoperative:preoperative magnification ratio of the posterior surface of the cornea was calculated in a theoretical eye model. RESULTS: Assuming the preoperative corneal thickness is 600.00 microm, the preoperative refractive power of the anterior corneal surface is 48.0 diopters (D), the refractive power of the cornea is 1.376, the ablation diameter is 6.0 mm, the postoperative corneal thickness is 480.00 microm, the postoperative refractive power of the anterior corneal surface is 38.0 D, and the posterior surface of the cornea does not change postoperatively, the apparent image of the posterior surface of the cornea becomes 0.778% smaller postoperatively. If the posterior radius of curvature of the cornea is 6.2 mm, it becomes smaller by 48.24 microm. If this change directly affects the difference map, the posterior surface of the cornea moves forward by 48.24 microm. CONCLUSION: The results correspond to the amount of ectasia in previous reports. This artifact may explain the apparent ectasia detected by Orbscan.

Artifacts↗
PubMed2005

Dioptric changes in eyes with reversed intraocular lenses.

PURPOSE: To theoretically calculate refractive changes in eyes with reversed intraocular lenses (IOLs). SETTING: Nara Medical University, Nara, Japan. METHODS: With the ray-tracing method, the refractive changes in a theoretical eye model with a reversed IOL in the capsular bag were calculated. Data for 3 models, anterior biconvex (MA60AC, Alcon), posterior biconvex (MA60BM, Alcon), and convex plano (UV2565T, Menicon), were provided by the manufacturer and used in the analysis. RESULTS: Using the assumption that the axial length varied from 22 to 27 mm, the anterior-biconvex IOLs elicited small refractive changes when reversed. The posterior-biconvex IOLs elicited a significant myopic shift (up to 0.90 diopter [D]) when reversed. The convex-plano IOLs elicited a significant hyperopic shift (up to 2.01 D) when reversed. CONCLUSIONS: Anterior-biconvex IOLs with similar anterior and posterior radii of curvature will not cause large diopter surprises when reversed. High-power posterior-convex IOLs will cause significant myopic diopter surprises when reversed. Both these changes shift toward myopic if the postoperative anterior chamber depth (ACD) becomes shallow. Medium- to high-power convex-plano IOLs will cause a large hyperopic shift when reversed. This hyperopic shift decreases if the postoperative ACD becomes shallower.

Humans↗
PubMed2005

Influence of intraocular lens optical design on high-order aberrations.

PURPOSE: To compare differences in high-order aberrations (HOAs) between 2 intraocular lens (IOL) optical designs. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHOD: Sixty eyes that had uncomplicated phacoemulsification and IOL implantation were assigned to 1 of 2 groups based on the type of IOL optical design: more posteriorly curved biconvex shape (AcrySof MA30BA, Alcon) (n=30 eyes) or more anteriorly curved biconvex shape (AcrySof MA30AC) (n=30 eyes). All patients had best corrected visual acuity better than 20/25. High-order aberrations were measured using a Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters. RESULTS: At 4.0 mm aperture diameters, there were no differences between the 2 groups in HOAs (P>.05, Mann-Whitney U test) in the cornea and the whole eye. At 6.0 mm aperture diameters, MA30AC eyes had a smaller amount of spherical-like aberrations (P=.043) than MA30BA eyes; however, there were no significant differences between the 2 groups in coma-like aberrations and total aberrations in the whole eye (P>.05). At 6.0 mm aperture diameters, there were no differences between the 2 groups HOAs in the cornea. (P>.05). CONCLUSION: The optical design of the spherical IOL influenced the spherical-like aberrations in the whole eye. This may reduce retinal image quality.

Acrylic Resins↗