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Biomedical subjects

Y Oshima

Publications and source records attributed to Y Oshima.

At least 127 records · Page 7Linked to original sources
PubMed1998

Transscleral fixation of acrylic intraocular lenses in the absence of capsular support through 3.5 mm self-sealing incisions.

PURPOSE: To evaluate the safety and efficacy of transscleral ciliary sulcus fixation of acrylic intraocular lenses (IOLs) through small incisions in the management of secondary IOL implantation. SETTING: Department of Ophthalmology, Osaka Rosai Hospital, Osaka, Japan. METHODS: This retrospective study consisted of 28 patients (30 eyes) who had transscleral fixation of acrylic IOLs through 3.5 mm incisions. All patients were followed for a minimum of 6 months in several different clinical settings. Data on visual acuity, keratometry, and central corneal endothelial cell count were evaluated preoperatively and postoperatively. The refractive error achieved and incidence of postoperative complications were determined. RESULTS: Uncorrected visual acuity (UCVA) improved in all eyes. Of the 18 eyes without pre-existing pathology, 11 (61.1%) had a UCVA of 20/40 or better from 1 week postoperatively. Best corrected visual acuity was unchanged in 24 eyes (80.0%) and improved by 2 Snellen lines or more in 5 eyes (16.7%) at the final examination. Self-sealing wound adaptation was achieved in 25 eyes (83.3%). The mean scalar shift in keratometric cylinder was 1.25 diopters (D) at 1 day postoperatively, 1.17 D at 1 week, and 1.06 D at 3 months. The rate of central corneal endothelial loss 6 months postoperatively averaged 7.84%. No intraoperative complications that were directly associated with acrylic IOL implantation occurred. Postoperative complications that included transient ocular hypertension, slight vitreous hemorrhage, and IOL malposition were found in a small population but resolved spontaneously without further surgical intervention. CONCLUSIONS: The good visual outcomes and low incidence of complications achieved in the present study indicate that acrylic IOLs positioned through small incisions might be considered for ciliary sulcus fixation. However, evaluation of this technique in a large population over the long term is required.

Acrylic Resins↗
PubMed1998

A patient with a hemoglobin variant (Hb JLome) unexpectedly detected by HPLC for glycated hemoglobin (Hb A1c).

A rare hemoglobin variant, Hb JLome, was identified by chance in a male patient with diabetes mellitus (DM). The patient had no evidence of anemia or hemolysis. However, when his glycated hemoglobin (Hb A1c) was examined by high-performance liquid chromatography (HPLC) to assess the state of his DM, an abnormal Hb was unexpectedly detected on the chromatogram. The morphology of the red blood cells was normal. A fast-moving band as well as a normally moving Hb band, of roughly equal intensities, were observed by cellulose acetate membrane electrophoresis. The oxygen equilibrium curve was essentially normal (P50 = 3.59 kPa). In other words, the ability of the patient's Hb to carry oxygen was nearly the same as that of typical Hb A. The stability of his Hb in isopropanol was normal, and all the functions of his Hb that were tested were essentially normal. The identity of the abnormal Hb was finally determined, by sequencing the globin gene, to be Hb JLome, which is produced by a point mutation changing AAG to AAC at the 59th codon in exon 2 of the Hb beta chain. As previously reported, replacing the beta 59 lysine with asparagine does not affect the function of Hb or the red blood cells. There have been only five documented cases of Hb JLome in Japan. Interestingly, all these cases are from Kyushu Island. When an abnormal chromatogram for Hb A1c is unexpectedly obtained, it is worthwhile searching for an abnormal Hb, even if there are no signs that suggest its existence, such as anemia, hemolysis, erythrocytosis, or cyanosis.

Aged↗
PubMed1998

A vitrectomy improves the transfection efficiency of adenoviral vector-mediated gene transfer to Müller cells.

The neural retina is a logical target of gene therapy for various ocular diseases. We developed a new gene delivery method to the neural retina using an adenoviral vector with a high degree of gene transfection efficiency and less functional damage. An adenoviral vector bearing the lacZ gene (AdCALacZ) was injected into the eyes of adult Wistar rats after an SF6 compression gas vitrectomy and left for 30 min followed by washing with balanced salt solution (BSS) (method A). Three other methods, comprising a simple intravitreal injection (method B), an intravitreal injection after an SF6 compression gas vitrectomy (method C) or a subretinal injection (method D), were also studied. The gene expression was examined 6 days after the AdCALacZ injection. An immunohistochemical study for antivimentin, antiglial fibrillary acidic protein and anti S100 protein antibodies showed the neural retinal cells (Müller cells) to be primarily transfected by methods A, B and C, while only a few cells were transfected by method D. The expression of beta-galactosidase was visualized by X-gal staining and the positive areas on each hemiflat mount specimen were measured by an image analyzer and then were adopted as a value of gene transfer efficiency. The highest degree of gene expression was obtained by methods A (23.2% of total retinal area) and C (19.8%), while the lowest degree was obtained by method B (8.9%). The inflammation was observed in all eyes and the value of inflammation was quantified as the average inflammatory cell number in each microscopic field (cells per fields). A moderate degree of inflammation was induced by methods B (28.3 cells per field) and C (27.5 cells per field) and a minimal degree of inflammation was induced by method A (11.2 cells per field). We evaluated the retinal function by measuring an electroretinogram (ERG). The amplitudes of the ERG were depressed in all eyes treated with AdCALacZ. This depression was manifested most by methods B and C, and least by method A. The deterioration in the ERG findings seemed to correlate with the intensity of inflammation. Our study showed that an intravitreal injection with an adenoviral vector can transfer the genes to the neural retinal cells and therefore a vitrectomy and the subsequent removal of the adenoviral vector, can thus significantly improve the transfection efficiency and also reduce the degree of functional damage.

Adenoviridae↗
PubMed1998

Targeted gene transfer to corneal endothelium in vivo by electric pulse.

A novel method of in vivo targeted gene transfer to intentionally selected areas of the corneal endothelium was developed. Plasmid DNA with the lacZ gene coding for beta-galactosidase was injected into the anterior chamber of adult Wistar rats, and eight pulses of electricity at intensities ranging from 5 to 40 V/cm were delivered for 50 ms to the cornea with a specially designed electric probe in order to determine the effect of gene transfer on the corneal endothelial cells. Gene expression was visualized by enzymatic color reaction using X-gal in enucleated eyes on days 1, 3, 7, 14 and 21 after gene transfer. The treated eyes were then photographed and the X-gal-positive areas were evaluated by an image analyzer. The ratios of the areas (X-gal-positive area/area of entire corneal endothelium x 100%) were then calculated to determine gene transfection efficiency. The expression of beta-galactosidase was clearly detected in the cytoplasm of the corneal endothelial cells as early as day 1 and lasted until day 21. The most intense gene expression was observed on days 1 and 3 (5.21% on day 1 and 6.45% on day 3). The expression of beta-galactosidase on day 3 was most evident following delivery of 20 V electric pulses (0.09% at 5 V, 0.03% at 10 V, 6.45% at 20 V). beta-Galactosidase expression was limited to the corneal endothelial cells in highly selected areas and no beta-galactosidase expression was detected in any other intra- or axtraocular tissues. In addition, no cell damage was apparent in the cornea and no inflammation was detected in any other intraocular tissues. Thus, low-voltage electric pulses successfully transferred the gene of interest to highly selective areas of the corneal endothelium without inducing any pathological changes. This targeted gene transfer method appears to have great potential for use in gene therapy for ocular diseases.

Animals↗
PubMed1998

Postischemic changes of

Sequential alterations of [3H]nimodipine and [3H]ryanodine binding in gerbils were investigated in selectively vulnerable regions, such as the striatum and hippocampus, 1 h to 7 days after 10 min of transient cerebral ischemia. [3H]Nimodipine binding showed no significant changes in the striatum and hippocampus up to 48 h after ischemia. Seven days after ischemia, however, a severe reduction in [3H]nimodipine binding was observed in the dorsolateral striatum, hippocampal CA1 (stratum oriens, stratum pyramidale and stratum radiatum) and hippocampal CA3 sector. On the other hand, [3H]ryanodine binding showed a significant increase in the hippocampus 1 h after ischemia. Five hours after ischemia, a significant reduction in [3H]ryanodine binding was observed only in the hippocampal CA1 sector. Thereafter, the striatum and hippocampus showed no significant alterations in [3H]ryanodine binding up to 48 h after ischemia. After 7 days, a marked reduction in [3H]ryanodine binding was observed in the striatum and hippocampus which were particularly vulnerable to ischemia. These results demonstrate that postischemic alteration in [3H]nimodipine and [3H]ryanodine binding is produced with different processes in the hippocampus. They also suggest that the mechanism for striatal cell damage caused by transient cerebral ischemia may, at least in part, differ from that for hippocampal neuronal damage. Furthermore, our findings suggest that abnormal calcium release from intracellular stores may play a pivotal role in the development of hippocampal neuronal damage. Copyright Rapid Science Ltd

Journal Article↗
PubMed1998

Effect of NG-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, on neurotransmitter receptor systems in aged rats.

In order to examine the effect of age and nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), we studied the changes on major neurotransmitter receptor systems in 6 (adult) and 24-month-old (aged) Fischer male rats using receptor autoradiography. L-NAME was administrated intraperitoneally in aged rats once a day for 4 weeks. [3H]QNB (quinuclidinyl benzilate), [3H]HC (hemicholinium-3), [3H]muscimol, [3H]SCH 23390 ([N-methyl-3H]R[+]-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-7-ol-benzazepine), [3H]nemonapride and [3H]mazindol were used as markers of muscarinic acetylcholine receptors, high-affinity choline uptake sites, GABAA (gamma-aminobutyric acidA) receptors, dopamine D1 receptors, dopamine D2 receptors and dopamine uptake sites, respectively. The age-related change in [3H]muscimol binding in the brain was more pronounced than that in [3H]QNB, [3H]HC, [3H]SCH 23390, [3H]nemonapride and [3H]mazindol binding. Chronic treatment (4 weeks) with L-NAME caused no significant changes in [3H]QNB, [3H]muscimol, [3H]SCH 23390 and [3H]nemonapride binding in most areas of aged rat brain, as compared with vehicle-treated aged animals. However, chronic treatment with L-NAME caused a significant reduction in [3H]HC and [3H]mazindol binding in any brain regions of aged rats in comparison with the vehicle-treated aged animals. These results demonstrate that the GABAergic system is more susceptible to aging processes than cholinergic and dopaminergic systems in the brain. Furthermore, our findings suggest that nitric oxide may play some role in the regulation of choline uptake and dopamine uptake systems during aging processes. Copyright 1998 Lippincott Williams & Wilkins

Journal Article↗
PubMed1998

Scanning laser ophthalmoscope microperimetric assessment in patients with successful laser treatment for juxtafoveal choroidal neovascularization.

PURPOSE: To evaluate fixation stability and changes in retinal function in patients with laser scar expansion after successful macular photocoagulation for juxtafoveal choroidal neovascularization (CNV). METHODS: A consecutive series of 35 patients was examined in this prospective study. Only patients who had been successfully treated with laser photocoagulation for juxtafoveal CNV and who could be followed over a period of at least 6 months were enrolled. Fixation stability and localized light sensitivity were examined by microperimetry using a scanning laser ophthalmoscope. Visual acuity was measured 2 weeks and 3 and 6 months after the laser treatment. The correlation between changes in the logarithm of the minimum angle of resolution (LogMAR) visual acuity and the distance between fixation and the center of the fovea was evaluated. RESULTS: Of 22 eyes of 20 patients that underwent data analysis, laser scar expansion was observed in 16 (72.7%). Ten (62.5%) of the 16 eyes had relative scotomas corresponding to the expanded laser scars. Mean laser scar expansion ratio was 28.7% in the ARMD group and 109.2% in the myopia group, a statistically significant difference (P < 0.01). The change in LogMAR visual acuity was significantly correlated with the distance of fixation locus from the center of the fovea (r = 0.76). CONCLUSIONS: Laser scars produced by photocoagulation for juxtafoveal CNV may expand and extend into the fovea, causing secondary retinal dysfunction. Scanning laser ophthalmoscopic assessment may be useful in evaluating fixation stability and subclinical changes in retinal function surrounding the laser scars before visual disturbance appears.

Aged↗
PubMed1998

Pharmacological properties of pteleprenine, a quinoline alkaloid extracted from Orixa japonica, on guinea-pig ileum and canine left atrium.

We have investigated the pharmacological properties of pteleprenine, a quinoline alkaloid, on contractile responses of the guinea-pig ileum and on inotropic responses of the canine left atrium. Although pteleprenine (0.1-1 microM) had no effect on the contraction of the ileum induced by acetylcholine at 10 microM it significantly inhibited acetylcholine-induced contraction of the ileum. Pteleprenine (0.1-10 microM) reduced nicotine induced-contraction of the ileum in a concentration-dependent manner yet had no maximum relaxant effect even at a concentration of 10 microM. From Schild analysis the pA2 of pteleprenine on the guinea-pig ileum was found to be 6.6. The contraction of the ileum induced by 10 microM 1,1-dimethyl-4-phenylpiperazinium, a specific agonist of nicotinic acetylcholine receptors, was concentration-dependently suppressed by 10 nM-10 microM pteleprenine. In contrast, 0.1-10 microM pteleprenine did not antagonize the acetylcholine- and nicotine-induced negative inotropic contractile responses of the canine left atrium. These results show that pteleprenine has inhibitory action against nicotinic acetylcholine receptors in the guinea-pig ileum but not in the canine left atrium. Our findings also suggest that pteleprenine might be a novel lead compound as a nicotinic receptor antagonist.

Acetylcholine↗
PubMed1998

Symptomatic spinal arachnoid cyst triggered by seat belt injury--case report.

A 49-year-old male presented with a symptomatic thoracic intradural arachnoid cyst triggered by seat belt trauma, which appeared within 3 weeks following a traffic accident. The initial symptom was a dull back pain induced immediately after the accident. Three and half months later, magnetic resonance (MR) imaging diagnosed the cystic nature of the lesion consistent with a low intensity on T1-weighted image which extended dorsally between the T-4 and T-6 levels. One month later, MR imaging showed that this cystic mass had enlarged in the anteroposterior direction associated with developing clinical symptoms. The final diagnosis of arachnoid cyst was made based on surgical findings and histological examinations. The spinal arachnoid cyst was probably a congenital arachnoid cyst or diverticula originating from the septum posticum which became enlarged due to sudden increase of intra-abdominal pressure caused by the fastened seat belt during the accident.

Accidents, Traffic↗
PubMed1998

[Risk factors for sudden death during hospitalization].

To determine the risk factors for sudden deaths in hospitalized patients, 209 patients (103 men and 106 women, age 76.7 +/- 12.6 years old, mean +/- S.D.) who died in 1996 were divided into two groups and their records were analyzed. One group, the sudden death group (SD), consisted of 16 patients who had stayed in the hospital for 2 weeks or more before the onset of symptoms that led to death within 24 hours. Those who died more than 24 hours after symptoms began were placed into the non-sudden death group (NSD). Fourteen patients who died within 2 weeks of admission were not analyzed in this study. Comparing the data of the two groups led to the following findings. First, the major causes of death in the SD group were exacerbation of chronic cardiac failure (5 cases), acute cardiac failure (2 cases), exacerbation of chronic respiratory failure (2 cases) and acute respiratory failure (2 cases). Second, patients in the SD group were significantly older than those in the NSD group, and had significantly more prescriptions for digitalis. Third, patients in the SD group had higher levels of hemoglobin and hematocrit, lower levels of BUN and a higher cardiothoracic ratio. Fourth, patients in the SD group had a higher incidence of ST abnormalities and T wave abnormalities in their electrocardiograms. Brugada syndrome or long QT syndrome were not seen in either group. Taken together, these findings suggest that aged patients with cardiac failure and myocardial ischemia may be at higher risk of sudden death.

Aged↗
PubMed1998

Suppression of HIV replication by dominant negative mutants of HIV-1 (review).

Various gag mutants of human immunodeficiency virus type 1 (HIV-1) generated in vitro were evaluated for their potentials to suppress the replication of wild-type (wt) virus. A single-round of wt virus replication in the presence of various mutant proteins was quantitatively monitored by transfection and infection experiments. Out of 38 mutants examined, 15 were demonstrated to interfere with the replication of wt HIV-1 at early and/or late viral replication phase. Some of these mutants were also effective against the replication of wt HIV-2. In this review, we focus on the mutants, which are able to act against a wide variety of HIV, and are very useful for future gene therapy against AIDS.

HIV-1↗
PubMed1998

[A longitudinal cohort study on the relation between physical condition and masticatory ability in the elderly].

The present study was conducted to determine the relation between physical condition and masticatory ability. The subjects were residents over 65 years old living in three different areas in Sagae City. The physical conditions assessed were height, weight, rate of body fat, grip strength, and bone mineral density. Masticatory ability was evaluated by the test jelly method. The results were as follows: 1) There was a difference in physical condition among subjects from the three residential areas. 2) For males, the group who maintained their masticatory ability exhibited better physical condition than those who did not. As for females, however, the physical condition was more strongly affected by age than masticatory ability.

Aged↗
PubMed1998

[Neural protective agents, propentofylline (PPF) could induce apoptotic cell death in the human glioma cells: analysis of Bcl-2 and Bax alpha/Bax beta expressions].

In the previous study, we have shown that propentofylline (PPF) could induce the cellular differentiation and apoptosis-related growth regression in the human glioma cell lines. Its biological functions were partly due to the increasing endogeneous NGF and its high affinity receptor, trk A productions. Although little has been known about the precise machinary regulating the propentofylline induced apoptosis. Recently, we have found that propentofylline could modulate some apoptosis related genes products in the glioma cell lines, i.e. NGF, trk A mRNA levels and Fas protein expressions were increased, whereas bcl-2 mRNA level was decreased. In the present study, we examined the apoptotic signal cascade, especially focusing on the expressing pattern of Bcl-2/Bax gene products. In the normal human astrocyte cells, Bax-beta was markedly expressed, whereas Bcl-2 and Bax-alpha proteins and mRNA were weakly or even nondetectable. Accordingly, Bax beta might be a dominant variant in the normal glial cells, which could have the appropriate balance of proapoptotic (Bax beta) and anti-apoptotic proteins (Bcl-2). In the glioma cells, we showed the over-expressions of Bcl-2 and Bax alpha compared with the normal counterparts. According to Bax dominant theory, Bax, not Bcl-2 may have a major role in regulating apoptosis by means of homodimerization. In might be implied that in the glioma cells, excessive expressions of Bcl-2 and Bax alpha would favor the formation of the Bax alpha/Bax beta heterodimer or the Bax beta/Bcl-2 heterodimer rather than the Bax beta/Bax beta homodimer, which might be presumed to be functional proteins. And finally the increasing relative ratio of Bax alpha/ Bax beta or Bax beta/Bcl-2 to Bax beta/Bax beta could allow the tumor cells to survive. Thus over-expression of the bcl-2 and bax alpha gene renders the glioma cells resistant to apoptosis. In the present study, PPF could promote Bax beta over-expression and Bcl-2 retardative expression in the glioma cells, whereas had no effect on Bax alpha expression. Therefore, PPF might promote apoptotic cell death through the mechanism that restore the glioma cells to the appropriate balance of proapoptotic and anti-apoptotic proteins like as normal astrocytes. Our results indicated that propentofylline might have a potential role as apoptotic modulators in the human glioma cell lines, not only its protective activities against neuronal ischemic damages.

Apoptosis↗
PubMed1998

[Induction of apoptosis through NGF/p75NTR in human glioma cells treated with propentofylline].

Propentofylline (PPF) is a xanthine derivative and it has been reported that PPF stimulated the synthesis/secretion of nerve growth factor (NGF) by cultured astroglial cells. We have reported that PPF induced apoptosis in human glioma cells and as its mechanism, up-regulation of NGF, Fas, Bax beta and down-regulation of Bcl-2 were assumed. Recent studies demonstrated the presence of apoptosis induced via NGF/p75NTR in developmental neuron, oligodendroglia. In the present study, to examine whether signal cascade via NGF/p75NTR participates the apoptosis in human glioma cells treated with PPF, we investigated the immunohistochemical study using anti-mouse monoclonal antibody, immunoprecipitation and northern blot analysis for p75NTR, NF-kappa B in human glioma cells (U251MG, T98G, U87) treated with PPF. We observed the up-regulation of p75NTR, translocation of NF-kappa B to the nucleus after treatment with PPF in these cell lines. According to above results, it is assumed that apoptosis in human glioma cells treated with PPF was induced via NGF/p75NTR.

Apoptosis↗
PubMed1998

[Surgical indications and results of primary pars plana vitrectomy for rhegmatogenous retinal detachments].

To evaluate the efficasy of primary vitrectomy for uncomplicated rhegmatogenous retinal detachment associated with posterior hyaloid separation, a series of 63 eyes were reviewed retrospectively. The criteria for vitrectomy included not only eyes with posterior retinal breaks but also those with multiple peripheral retinal breaks. The reattachment rate was 92.1% (58 eyes) after the initial surgery, and finally this increased to 100%. Of the 46 eyes with macular detachment, good visual rehabilitation, i.e., visual acuity improved by 5 or more lines, was obtained in 71.8% (33 eyes) one month postoperatively. There was no statistically significant difference in the reattachment rate whether an encircling procedure was also done or not. In eyes with lens opacity, cataract surgery was also done and intraocular lenses were implanted uneventfully in all but one myopic case. No serious complications such as proliferative vitreoretinopathy were found throughout the follow-up period except for the high incidence (53.8%) of cataractous progression. The results indicate that vitrectomy, removing the peripheral vitreo-retinal traction directly, is an effective procedure for primary rhegmatogenous retinal detachment. Vitrectomy combined with cataract surgery is also proposed as a valuable strategy in selected cases to maintain visual rehabilitation.

Cataract Extraction↗
PubMed1998

[Long-term results after simple vitrectomy for age-related macular degeneration with vitreous hemorrhage].

We reviewed the cases of 10 eyes with vitreous hemorrhage secondary to submacular hemorrhage associated with age-related macular degeneration, in which vitrectomy was performed without subretinal management. Vitreous hemorrhage occurred within 3 weeks of submacular hemorrhage. After vitrectomy, residual subretinal hemorrhage was rapidly absorbed and choroidal neovascularization was undetectable. After the surgery visual acuity improved over that of submacular hemorrhage in 5 eyes. Mean follow-up was 25 months and final visual acuity was 0.2 or better in 6 eyes (60%). Final visual outcome was highly corelated with the period from subretinal hemorrhage to vitrectomy, the thickness of subfoveal hemorrhage at vitrectomy, position of choroidal neovascularization, and duration of subretinal hemorrhage. Simple virectomy might be effective to stabilize submacular changes and improve visual acuity.

Age Factors↗