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Biomedical subjects

Yoshiaki Hara

Publications and source records attributed to Yoshiaki Hara.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effect of tilt of 2 acrylic intraocular lenses on high-order aberrations.

PURPOSE: To investigate the high-order aberrations (HoAs) in pseudophakia between 2 foldable acrylic intraocular lenses (IOL) with differences in the tilt of IOL. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHOD: Sixty-four eyes that had uncomplicated phacoemulsification and IOL implantation were assigned to 1 of 2 groups: Acryfold 60BB (HOYA [n=30 eyes]) and AcrySof MA60AC (Alcon [n=34 eyes]). All patients had best corrected visual acuity better than 20/25. High-order aberrations were measured using the Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters, and the IOL tilt and decentration were measured using Scheimpflug videophotography. RESULTS: There was a significant difference in the IOL tilt (60BB=2.22 degrees +/- 1.44 (SD), 60AC=3.18 +/- 1.84 degrees; P=.041, Mann-Whitney U test), but no difference in IOL decentration (P>.05). In the cornea, there were no differences between the 2 groups in HoAs at 4.0 mm and 6.0 mm aperture diameters (P>.05, Mann-Whitney U test). In the whole eye, there was no difference between the 2 groups in spherical-like aberrations, coma-like aberrations, and total aberrations at the 4.0 mm and 6.0 mm aperture diameters (P>.05). The compensation of the internal optics with the 60BB group was better than with the 60AC group for coma-like (P=.037) and total aberrations (P=.010) at 6.0 mm aperture diameter. CONCLUSION: The smaller tilt of the IOL induced more compensation for the coma-like and total aberrations at the 6.0 mm aperture diameter. The IOL tilt should be small, especially in a large pupil, with regard to HoAs.

Aberrometry↗
PubMed2005

Posterior corneal surface changes after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate posterior corneal surface topographic changes after hyperopic laser in situ keratomileusis (H-LASIK) using Orbscan I (Orbtek, Inc.). SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: In 25 eyes of 15 patients who had H-LASIK, the posterior corneal surface was measured with slit-scanning corneal topography (Orbscan I) preoperatively and 1 year postoperatively. The center as a fit zone and calculated posterior corneal surface changes were taken at 4 points: nasal, temporal, superior, and inferior sides in the 5.0 mm diameter. The posterior corneal topographic changes were analyzed using an analysis of variance. The postoperative:preoperative magnification ratio of the posterior corneal surface was calculated in a theoretical eye model. RESULTS: When a "+" reading was defined as the forward displacement and "-" was defined as the backward displacement, the mean posterior corneal topographic changes were -2.8 microm +/- 27.9 (SD) at the nasal side, -4.5 +/- 27.8 microm at the temporal side, -3.9 +/- 20.1 microm at the superior side, and -2.3 +/- 20.1 microm at the inferior side. The posterior corneal surface between any 2 examined points showed no significant difference after H-LASIK. In addition, the hypothetical change in the posterior cornea was -8.3 microm after +3.0 diopter H-LASIK, which was approximately closer to the study results. In each side, the amount of the attempted correction was significantly correlated with the posterior corneal topographic change. CONCLUSIONS: Clinical measurement of the posterior corneal displacement after H-LASIK with Orbscan revealed a backward shift. This change corresponded to the hypothetical artifactual changes with Orbscan; that is, changes in the magnification ratio.

Adult↗
PubMed2005

A child with epilepsy in whom multifocal VEPs facilitated the objective measurement of the visual field.

PURPOSE: We investigated whether visual field defects can be objectively evaluated by using multifocal visual evoked potential (multifocal VEP) in children with epilepsy in whom it is difficult to measure the visual field. METHODS: First, to determine normal waves in multifocal VEP, recording was performed by using a VERIS Junior Science (Mayo, Aichi, Japan) in 21 healthy children (21 eyes) consisting of 12 boys and nine girls aged 6 to 15 years (mean age, 11.4 years). Responses from eight sites in each subject were divided into four quadrants (superior and inferior temporal quadrants and superior and inferior nasal quadrants). In each quadrant, two response waves were grouped and averaged; peak latency and amplitude were used for assessment. In a child with epilepsy in whom kinetic or static perimetry was impossible, multifocal VEPs were recorded and compared with the peak latency and amplitude in the healthy subjects. RESULTS: In the 21 healthy children, no significant differences were observed in the peak latency or amplitude among four quadrants by one-way analysis of variance. Multifocal VEPs in the child with epilepsy showed abnormal waves in the right hemivisual field, which corresponded to the lesion observed with magnetic resonance imaging. CONCLUSIONS: The objective evaluation of visual field defects by using multifocal VEP may be useful in children with epilepsy in whom kinetic/static perimetry as a subjective examination is difficult.

Adolescent↗
PubMed2004

High-order aberrations with Hydroview H60M and AcrySof MA30BA intraocular lenses: comparative study.

PURPOSE: To compare differences in high-order aberrations between 2 intraocular lenses (IOLs), the Hydroview H60M (Bausch & Lomb) and AcrySof MA30BA (Alcon). SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHOD: Twenty-four eyes of 14 patients with a Hydroview IOL and 25 eyes of 20 patients with an AcrySof IOL who had uneventful phacoemulsification and a best corrected visual acuity better than 20/16 from 6 to 12 months after surgery were evaluated. High-order aberrations were measured using a Hartmann-Shack aberrometer at 4.0 mm and 6.0 mm wavefront aperture diameters, and IOL tilt and decentration were assessed by Scheimpflug videophotography. RESULTS: There were no differences between the 2 groups in IOL tilt and decentration (P>.05, Mann-Whitney U test). In the cornea, there were no differences between the 2 groups in high-order aberrations at 4.0 mm and 6.0 mm aperture diameters (P>.05, Mann-Whitney U test). In the whole eye, there was a significant difference between Hydroview (mean 0.441 microm +/- 0.147 [SD]) and AcrySof (0.696 +/- 0.287 microm) IOLs in spherical-like aberrations at the 6.0 mm aperture diameter (P =.00008, Mann-Whitney U test); there were no differences between the 2 groups in other aberrations. CONCLUSIONS: The type of IOLs influenced spherical-like aberrations. The IOL's shape was a particularly important factor in spherical-like aberrations. The aberrations may affect night driving in certain individuals.

Acrylic Resins↗
PubMed2004

Long-term observation of the refraction with a reversed-optic posterior chamber intraocular lens.

A 73-year-old man had phacoemulsification and implantation of a posterior chamber intraocular lens (PC IOL) in both eyes. In the right eye, the optic was unintentionally reversed in the bag. In the left eye, the posterior capsule was ruptured and the IOL haptics were fixated in the ciliary sulcus. The refraction in the sulcus-fixated left eye was stable from 1 month to 4 years. The right eye had a myopic shift at 1 month, with a regression of 1.50 diopters that continued for 2 years. The final IOL position in the right eye was 0.25 mm anterior to the position predicted by the SRK/T formula. It took 2 years for the refraction in the eye with the reversed-optic PC IOL to become stable. A large myopic shift and gradual regression in refraction may stem from a different wound-healing reaction than that of properly fixated IOLs.

Aged↗
PubMed2004

Influence of intraocular lens tilt and decentration on wavefront aberrations.

PURPOSE: To investigate the influence of intraocular lens (IOL) tilt and decentration on higher-order aberrations (HOAs) using wavefront analysis. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: Forty eyes of 40 patients with a 5.5 mm optic, foldable acrylic IOL were examined 4 to 48 months postoperatively. Ocular wavefront aberrations of the central 4.0 mm aperture diameter were measured using a Hartmann-Shack aberrometer. Higher-order aberrations from the 3rd to 4th order were calculated using Zernike polynomials. The relationship between IOL tilt and decentration, measured with a Scheimpflug camera, and ocular HOAs were investigated. RESULTS: The correlation between IOL tilt and coma-like aberrations was significant (r=0.431, Spearman rank correlation coefficient; P=.007). However, the correlation between IOL tilt and the spherical-like and total aberrations was not significant (P>.05), nor was the correlation between IOL decentration and coma-like, spherical-like, and total aberrations (P>.05). CONCLUSIONS: Intraocular lens tilt influenced ocular coma-like aberrations. The quality of the retinal image may improve by reducing IOL tilt.

Aged↗
PubMed2004

[Successful hepatic arterial infusion therapy of CDDP/5-FU/IFN-beta3 for recurrent hepatocellular carcinoma].

A 52-year-old male patient was admitted to our hospital for a further examination of liver tumor. He was positive for hepatitis C virus antibody. CT scanning revealed two hyper vascular tumors at the lateral segment of the liver and another one located at segment 8, an indication of hepatocellular carcinoma (HCC). Ascites were not detected and major serological findings were T-Bil 1.1 mg/dl, Alb 3.5 g/dl, ICG R15 12% and PT 88%. Lateral segmentectomy and a partial resection of the segment 8 were performed at the same time. An insertion of catheter in hepatic artery via gastroduodenal artery was carried out. Dehydropyrimidine dehydrogenase (DPD) activity of the tumor was 157 pmol/min/mg proteins. Recurrence was detected one year after the operation at segments 4 and 8. Arterial infusion chemotherapy using CDDP (10 mg), 5-FU (1,000 mg) and IFN-beta 3MU (continuous infusion for 5 days) was started two months later, and a complete response was achieved. The chemotherapy continued as long as severe adverse effects were not observed. However, two months after the tumor disappearance, the treatment discontinued due to occlusion of the infusion system. Recurrence occurred in two months at the same location where the previous tumor was. In conclusion, these results suggest that arterial chemotherapy using CDDP/5-FU/IFN-beta against HCC may be beneficial.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

Accommodation obtained per 1.0 mm forward movement of a posterior chamber intraocular lens.

PURPOSE: To clarify the amount of accommodation per 1.0 mm forward movement of a posterior chamber intraocular lens (IOL). SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: A ray-focusing equation of pseudophakic eyes was obtained with the ray-tracing method using Mathematica((R)) computer software (Wolfram). At first, it was assumed that the anterior radius of curvature of the cornea was 7.7 mm, the thickness was 0.5 mm, and the refractive index was 1.3375, and an AcrySof IOL (Alcon) was implanted in the capsular bag. Anterior and posterior radii of curvature and IOL thickness data were provided from the manufacturer and inserted in the equation. Next, the amount of accommodation per 1.0 mm of forward movement of a posterior chamber IOL was calculated under the assumption that the axial length (AL) varied from 21.0 to 27.0 mm and the implanted IOL from 30.0 to 11.0 diopters (D). The AL was fixed at 24.0 mm, and the anterior radius of curvature was varied from 6.5 to 9.5 mm and the IOL from 10.0 to 30.0 D. Similar calculations were then performed. RESULTS: Under the assumption of a fixed corneal anterior radius of curvature of 7.7 mm, when the AL was 24.0 mm and the implanted IOL 20.0 D, 1.0 mm of forward IOL movement corresponded to 1.3 D of accommodation. When the AL was 21.0 mm and a the IOL 30.0 D, 1.0 mm of forward IOL movement corresponded to 2.3 D of accommodation. When the AL was 27.0 mm and the IOL 11.0 D, 1.0 mm of forward IOL movement corresponded to 0.8 D of accommodation. Similarly, when the anterior radius of corneal curvature was varied from 6.5 to 9.5 mm and the IOL from 10.0 to 30.0 D and the AL was fixed at 24.0 mm, 1.0 mm of forward IOL movement corresponded to 0.5 to 1.9 D of accommodation. CONCLUSIONS: Accommodation obtained per 1.0 mm of forward IOL movement varied with AL from 0.8 D in a long eye to 2.3 D in a short eye. It also varied with the corneal power. Thus, one should not state that 1.0 mm of forward IOL movement always corresponds to a certain amount of diopters of accommodation.

Accommodation, Ocular↗
PubMed2003

Evaluation of the corneal endothelium after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate corneal endothelial changes after hyperopic laser in situ keratomileusis (LASIK) considering overestimation and underestimation of the cell count measurement. SETTING: Department of Ophthalmology, Nara Medical University, Nara, Japan. METHODS: The data were from the clinical trial of the Nidek EC-5000 excimer laser for hyperopic LASIK. The mean correction was 3.59 diopters (D) +/- 1.54 (SD) (range 2.0 to 6.0 D). Using noncontact specular microscopy, the corneal endothelial changes in 25 eyes of 15 patients who had hyperopic LASIK were measured. Follow-up ranged from 6 months (n = 25) to 1 year (n = 21). The overestimation and underestimation of the corneal endothelial cell count that would occur after +5.0 D hyperopic LASIK was hypothetically calculated. RESULTS: The measured endothelial cell count per 1.0 mm(2) did not significantly decrease up to 1 year after hyperopic LASIK (preoperatively, 2508 +/- 395; at 1 year, 2814 +/- 349). The hypothetical calculation revealed that a +5.0 D hyperopic correction corresponded to a 0.1% underestimation of the corneal endothelial cell count. CONCLUSIONS: Underestimation of the corneal endothelial cell count after hyperopic LASIK was negligible. Hyperopic LASIK with the Nidek EC-5000 excimer laser did not significantly decrease corneal endothelial cells up to 1 year after surgery.

Adult↗
PubMed2002

Indocyanine green angiography in patients with human T cell-lymphotropic virus type 1 uveitis.

PURPOSE: To determine the indocyanine green (ICG) angiographic features and to evaluate the choroidal involvement of human T-cell lymphotropic virus type 1 (HTLV-1)-associated uveitis. METHODS: We performed ICG angiography using scanning laser ophthalmoscopy in 54 eyes of 27 patients (8 men and 19 women) diagnosed with HTLV-1 uveitis. The patient's mean age was 51.5 years with a range of 24-65 years. RESULTS: The early phase of ICG angiography revealed ICG leakage from the choroidal vessels in the posterior pole, hyperfluorescent spots that which were not detected with fluorescein angiography, and small hypofluorescent lesions in the macula which most likely corresponded to microcirculatory disturbances in the choriocapillaris. CONCLUSIONS: We suggest that the ICG angiographic findings reflect choroidal lesions such as infiltration with leukocytes and edema. ICG angiography may provide useful information on choroidopathy in HTLV-1 uveitis.

Adult↗
PubMed2002

[Damage control for thoracic injuries].

A critically injured chest trauma patient showing profound shock or cardiac arrest en route to the trauma center or in the emergency room sometimes requires emergency room thoracotomy and definitive repair. In some patients damage control must be performed because of the appearance of the deadly triad of hypothermia, acidosis, and coagulopathy. Indications for damage control are believed to be body temperature < 34 degrees C, pH < 7.2, and clinically uncontrollable bleeding. The strategy for damage control consists of three steps: step 1, rapid control of hemorrhaging and abbreviated surgery in the ER or OR; step 2, correction of hypothermia, acidosis, and coagulopathy and reevaluation of the injuries in the intensive care unit; and step 3, definitive surgery in the OR. Damage control procedures for chest injuries include aortic cross-clamping, hilar clamping, major vessel ligation, pulmonary tractotomy, simultaneously stapled pneumonectomy or lobectomy, cardiac stapling, balloon catheter tamponade, temporary intraluminal shunt, towel packing, towel clip closure, single en masse closure of the chest wall, etc. Every surgeon responsible for treating critical chest trauma patients should have knowledge of damage control and also be familiar with the techniques.

Acidosis↗
PubMed2002

[A study on cases of good apparent accommodation using an all-distance visual acuity chart and corneal shape analysis].

PURPOSE: As a part of an attempt to elucidate the mechanism of apparent accommodation, an evaluation was made of patients with good apparent accommodation using an all-distance visual acuity chart and corneal shape analysis. MATERIALS AND METHODS: The study was performed on 6 patients (7 eyes) in a good apparent accommodation group and 13 patients (15 eyes) in a poor apparent accommodation group. These were selected from patients who had undergone normal small-incision ultrasonic phacoemulsification and posterior chamber type single focus intraocular lens implantation. In these patients, all-distance visual acuity was measured using an AS-15(Kowa Co., Ltd.), and corneal shape analysis was performed using Orbscan (Orbtek Inc.). RESULTS: In all-distance visual acuity, gentle decline from far to near was noted in the poor apparent accommodation group, and the degree of decline was lower in the good apparent accommodation group. Also, a two-peak pattern, showing decline at first and then an increase, was observed in some of the cases. In corneal shape analysis, there was no specific pattern in the good apparent accommodation group. However, the difference between maximum refractive power and minimum refractive power of cornea in the ranges of 3, 5, and 7 mm in total optical power (TOP) was significantly higher in the good apparent accommodation group compared with the poor apparent accommodation group (TOP 3 mm: p = 0.0233, TOP 5 mm: p = 0.0306, TOP 7 mm: p = 0.0035). CONCLUSION: In the present study, there were three patterns in all-distance visual acuity in the good apparent accommodation group, showing a two-peak pattern, a flat pattern, and a gentle decline, and the pattern of gentle decline was observed more often than the other patterns. The results of the study also suggest that the gradient of corneal refractive power may be related to apparent accommodation.

Accommodation, Ocular↗
PubMedDate not supplied

Relationship between corneal aberrations and contrast sensitivity after hyperopic laser in situ keratomileusis.

PURPOSE: To evaluate the relationship between corneal aberrations and contrast sensitivity (CS) after hyperopic laser in situ keratomileusis (H-LASIK). METHODS: In 13 patients (13 eyes) who underwent H-LASIK, we measured CS and corneal topography preoperatively and at 1 year postoperatively. Photopic and scotopic CS values were measured at 3, 6, and 12 cycles/degree (cpd) using an MCT-8000 contrast tester. Corneal aberrations were determined from the data on corneal topography using CTView. The corneal high-order aberrations were defined as the sum of the third- and fourth-order aberrations in the 4-mm zone and the sum of the third- to sixth-order aberrations in the 6-mm-zone. RESULTS: Under scotopic conditions at 12 cpd, the changes in CS significantly correlated with changes in the corneal aberrations. Scotopic CS was significantly deteriorated by glare, but photopic CS was not significantly changed. H-LASIK induced a significant increase in corneal aberrations that positively correlated with the amount of correction, regardless of the improvement in logMAR corrected visual acuity. LogMAR corrected visual acuity did not significantly correlate with corneal aberrations. Furthermore, decentration significantly correlated with the changes in the 6-mm zone corneal aberrations. CONCLUSIONS: In eyes after H-LASIK, the changes in scotopic CS significantly correlated with those in the corneal aberrations, which might have resulted from decentration or ablation profiles in H-LASIK and a relatively small optical zone. Further studies will be needed to validate this relationship.

Adult↗
PubMedDate not supplied

Preparation of comb-type N-isopropylacrylamide hydrogel beads and their application for size-selective separation media.

A series of the comb-type poly(N-isopropylacrylamide) (NIPAM) gel beads were prepared by inverse suspension polymerization techniques. The comb-type NIPAM gel beads exhibited large volume change at 30 degrees C, and their deswelling rate, defined as the time required for half-shrinking, was 10 times faster than that of the normal-type NIPAM gel beads. The gel beads were utilized to concentrate dilute aqueous solutions of albumin, gamma-globulin, and vitamin B(12). The separation efficiencies of albumin and gamma -globulin with the comb-type NIPAM gel were 80% and 85%, respectively. Whereas those with normal-type NIPAM gel were 55% and 60%, respectively. The incorporation of grafted chains into gel makes the effective mesh size smaller. Therefore it induces the additional obstruction effects between the solutes and network and excludes the high molecular weight solutes. After they have extracted water, their rapid deswelling property makes the gel regenerate effectively by warming to release the absorbed water.

Acrylamides↗
PubMedDate not supplied

Volume phase transition of bovine vitreous body in vitro and determination of its dynamics.

The phase equilibrium property and structural and dynamical properties of bovine vitreous body was studied by macroscopic observation of swelling behavior and dynamic light scattering under various conditions. It was found that the vitreous body collapses into a compact state isotropically or anisotropically depending on the external conditions. The vitreous body collapses while maintaining the shape when the pH (</= 4) and the concentration of calcium ions (</= 1 mol/L) are changed, whereas it collapses along the orbital axis in a mixed solvent of methanol and water. From observations of the dynamics of light scattered by the vitreous body, intensity autocorrelation functions that revealed two independent diffusion coefficients, D(fast) = 7.8 +/- 1.5 x 10 (- 8) cm(2)/s and D(slow) = 3.8 +/- 0.60 x 10 (-9) cm(2)/s, were obtained. The diffusion coefficients were found to be statistically independent of position within a focal depth range of 1-1.5 mm. Divergent behavior in the measured total scattered light intensities and diffusion coefficients was observed as the concentration of calcium ion approached the critical threshold, 1 mol/L. Namely, a slowing down of the dynamic modes accompanied by increased "static" scattered intensities was observed. The divergent behavior in the scattered light intensities and diffusion coefficients was reversible. This is indicative of the occurrence of a phase transition upon calcium ion concentration.

Animals↗
PubMedDate not supplied

Effect of direct hemoperfusion with a polymyxin B immobilized fiber column on high mobility group box-1 (HMGB-1) in severe septic shock: report of a case.

Because of the many difficult aspects in the treatment of septic shock and poor outcome of this condition, establishing the most appropriate therapeutic strategy is problematic. Recently, high mobility group box-1 (HMGB-1) has been shown to activate inflammatory responses and to be a late mediator in endotoxemia and sepsis. Therefore, we considered that it might be worthwhile to investigate the therapeutic potential of HMGB-1 blockade in cases of septic shock.Herein, we describe the case of a patient with septic shock with hepatic portal venous gas caused by intestinal obstruction. Hepatic portal venous gas is a rare condition associated with significant radiographic findings and a fatal outcome. Our patient, however, recovered from severe septic shock and was saved by the use of direct hemoperfusion with a polymyxin B immobilized fiber column (DHP-PMX). This treatment resulted in a decrease in the serum levels of endotoxin, interleukin-6 (IL-6), and HMGB-1.

Aged, 80 and over↗