Biomedical subjects

Kenji Ohno

Publications and source records attributed to Kenji Ohno.

6 recordsLinked to original sources

PubMed2005

Bofutsushosan, a traditional Chinese formulation, prevents intimal thickening and vascular smooth muscle cell proliferation induced by balloon endothelial denudation in rats.

Bofutsushosan (BOF), a traditional Chinese formulation (Kampo formulation in Japanese), is widely used for patients with obesity and hyperlipidemia resulting from long-term inappropriate lifestyles. Since atherosclerosis, a lifestyle-related disease, is accompanied by an abnormal accumulation of vascular smooth muscle cells (VSMCs) in the intimal area of the artery, we investigated the preventive effect of BOF on intimal thickening. Oral administration of BOF extracts 3 d before and 7 d after balloon endothelial denudation dose dependently suppressed the intimal thickening and proliferation of VSMCs in the intimal area in rat carotid arteries. This model has a similar pathologic process to atherosclerosis and is considered to be an "accelerated atherosclerosis" model. BOF extract also dose dependently inhibited the migration of cultured VSMCs. BOF extract suppressed serum lipid levels, which are a major risk factor for atherosclerosis. These findings clarified the usefulness of BOF in cardiovascular risk-reduction therapy.

Animals↗

PubMed2002

Transplantation of cryopreserved human corneas in a xenograft model.

An ideal model to test methods of corneal storage for transplantation would simulate the environment of the grafted human cornea and predict the success of clinical corneal transplants (human to human). In this study, we tested such a model, the corneal xenograft (human to cat). Nine pairs of human corneas were transplanted into both eyes of nine recipient cats. One cornea of each pair was cryopreserved at -196 degrees C in 2.5 M dimethyl sulfoxide while the other was stored in preservative medium at 4 degrees C (control) for 6 +/- 2 (mean +/- SD) days before transplantation. One week after transplantation, the cats were euthanized and the eyes were examined. Three of the grafts (all cryopreserved) were clinical failures and showed no survival of donor corneal endothelial cells on scanning electron microscopy. The remaining six pairs of grafts were examined with a specular microscope and showed endothelial cell losses of 48 +/- 16% in cryopreserved and 8 +/- 16% in control corneas (p < 0.05). This survival is similar to survival in an earlier corneal perfusion model. The nine cryopreserved grafts were thicker than the control grafts, had fewer surviving keratocytes in the central stroma, and had more apoptotic central keratocytes (TUNEL assay). This failure rate in cryopreserved corneas clearly shows that this technique of cryopreservation was not adequate for clinical use. The corneal xenograft model can be used to study cellular survival and apoptosis in vivo after preservation as well as to test new methods of corneal preservation before initiating clinical trials.

Adolescent↗

PubMed2002

Keratocyte activation and apoptosis in transplanted human corneas in a xenograft model.

PURPOSE: To study keratocyte activation and cellular apoptosis in transplanted human corneas during the early postoperative period. METHODS: Ten human donor corneas preserved for 6 days at 4 degrees C were transplanted into the eyes of 10 adult cats. After confocal and specular microscopy in vivo 1 week after keratoplasty, the cats were killed, and the fixed corneas were examined by TUNEL assay and by scanning (SEM) and transmission electron microscopy (TEM). RESULTS: Abnormal keratocytes, in which portions of cell bodies and processes as well as nuclei were visible, were present in all corneas and occupied the anterior 16 to 562 microm of the stroma. By TEM in the same corneas, these abnormalities represented keratocytes that were activated to a repair phenotype. Only 0% to 1% of all corneal cells were apoptotic by TUNEL assay, except for the donor keratocytes near the wound, where 7% were apoptotic. The midstromal keratocyte density was decreased at 13,936 +/- 5,910 cells/mm(3) (mean +/- SD), and the endothelial cell density was 2,298 +/- 688 cells/mm(2), representing an endothelial cell loss of 7% +/- 16%. CONCLUSIONS: Substantial keratocyte activation and low levels of cellular apoptosis occur 1 week after human corneal transplantation. The human-to-cat xenograft model of corneal transplantation demonstrated endothelial cell loss and other clinical findings similar to human allografts. The model will be useful for preclinical testing of new methods of long-term corneal preservation and of donor endothelial cell augmentation, as well as the study of human corneal wound healing and keratocyte replacement during the early postoperative period.

Adolescent↗

PubMed1996

Referred pain distribution of the cervical zygapophyseal joints and cervical dorsal rami.

The purpose of this study was to determine the distribution of referred pain from the cervical zygapophyseal joints (C0/1 to C7/Th1) and the cervical dorsal rami (C3 to C7). The subjects were 61 patients who had occipital, neck, and shoulder pain of suspected zygapophyseal origin in whom pain was reproduced by injection of contrast medium into the joints or by electrical stimulation of the dorsal rami. Under fluoroscopic control, the zygapophyseal joints from C0/1 to C7/Th1 were stimulated by the injection of contrast medium and while electrical stimulation of the cervical zygapophyseal dorsal rami at segments C3 to C7 was performed during facet denervation. If injection or electrical stimulation reproduced the patient's usual pain, the distribution of referred pain was determined and the sites of referred pain were divided into 10 areas. A total of 181 joints and 62 segments were studied. Each joint and dorsal ramus produced referred pain with a characteristic distribution. The main distribution of referred pain was as follows. Pain in the occipital region was referred from C2/3 and C3, while pain in the upper posterolateral cervical region was referred from C0/1, C1/2, and C2/3. Pain in the upper posterior cervical region was referred from C2/3, C3/4, and C3, that in the middle posterior cervical region from C3/4, C4/5, and C4, and that in the lower posterior cervical region from C4/5, C5/6, C4, and C5. In addition, pain in the suprascapular region was referred from C4/5, C5/6, and C4, that in the superior angle of the scapula from C6/7, C6, and C7, and that in the mid-scapular region from C7/Th1 and C7.

Cervical Vertebrae↗

PubMedDate not supplied

Evaluation of optical function using a new point spread function analysis system in cataractous and pseudophakic eyes: preliminary results.

PURPOSE: To evaluate optical function in cataractous and pseudophakic eyes using the new point spread function (PSF) analysis system in a clinical setting. METHODS: We applied this new analysis system in the study of two cataractous eyes and one pseudophakic eye of two patients. Using a PSF analyzer, double-pass PSF was measured directly for each subject, and the single-pass modulation transfer function (MTF) and single-pass PSF were calculated. The simulated retinal images of various sizes of Landolt's rings and their contrast characteristics were also calculated by the PSF analyzer. RESULTS: The MTF and the contrast of the simulated retinal images degraded in cataractous eyes were compared with data for normal eyes; the degradation pattern depended on the opacification pattern. The MTF and the contrast of the simulated retinal images in the pseudophakic eye improved significantly compared with the cataractous eyes, although both values were lower in the pseudophakic eye than in young normal eyes. CONCLUSIONS: Our data showed degradation of optical function in cataractous and pseudophakic eyes in comparison with optical function in young normal eyes. If further accumulations of PSF data are made, it may be possible to establish an objective standard by which to measure the progression of cataract, as well as an objective indication for treatment in the future.

Aged↗

PubMedDate not supplied

Calculation of ocular single-pass modulation transfer function and retinal image simulation from measurements of the polarized double-pass ocular point spread function.

The single-pass modulation transfer function (MTF(sgl)) is an important numerical parameter that can help elucidate the performance and some processes of the human visual system. In previous studies, the MTF(sgl) was calculated from double-pass point spread function (PSF) measurements. These measurements include a depolarized reflection component from the retina that introduces a measurement artifact, and they require long acquisition times to allow averaging to reduce speckle. To solve these problems, we developed a new ocular PSF analysis system (PSFAS) that uses polarization optics to eliminate the depolarized retinal reflection component, and a rotating prism to increase measurement speed. Validation experiments on one patient showed that the MTF(sgl) measured by PSFAS agrees closely with the MTF calculated from contrast sensitivity measurements. A simulated retinal image was calculated by convolution of Landolt rings with the calculated single-pass PSF provided by the PSFAS. The contrast characteristic then was calculated from the simulated retinal images. These results indicate that the MTF(sgl) obtained using the PSFAS may be a reliable measure of visual performance of the optics of the eye, including the optical effects of the retina. The simulated retinal images and contrast characteristics are useful for evaluating visual performance.

Adult↗