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Biomedical subjects

A Kanai

Publications and source records attributed to A Kanai.

At least 73 records · Page 4Linked to original sources
PubMed1998

Mitochondrial DNA mutations in Japanese patients with optic neuropathy unassociated with a mutation at nucleotide position 11,778.

We examined for mitochondrial DNA (mtDNA) mutations at nucleotide positions(nt) 3460, 14,484, 9438, 9804, and 15,257 in ten Japanese patients with idiopathic optic neuropathy unassociated with a mutation at nt11,778. The mtDNAs were amplified by polymerase chain reaction (PCR), the products were digested with restriction enzymes, and the sizes of the fragments were analyzed on 8% polyacrylamide gel. Of the ten patients, one had an mtDNA mutation at nt3460 and another patient had a mutation at nt14,484. We suggest that mtDNA mutations in Japanese patients with optic neuropathy unassociated with a mutation at nt11,778 should be further investigated.

Adolescent↗
PubMed1998

Visual function in retinitis pigmentosa related to a codon 15 rhodopsin gene mutation.

To determine the phenotype of a Japanese family in which retinitis pigmentosa cosegregates with a rhodopsin gene mutation, i.e. an asparagine-to-serine change at codon 15 (Asn-15-Ser), 5 affected and 5 unaffected members of one pedigree underwent several ophthalmic examinations as well as Ganzfeld electroretinography (ERG) and multifocal ERG. Genomic DNA samples were analyzed by PCR amplification, sequencing and restriction enzyme digestion. A codon 15 rhodopsin gene mutation (Asn-15-Ser) was found in all affected members. The region of pigmentary degeneration was localized in the lower hemiretina, and visual field defects corresponded to the retinal pigmentary changes. Scotopic ERG amplitudes, rather than photopic ERG amplitudes, were reduced. Multifocal ERG revealed a low magnitude of response density, even for the upper hemiretina, which showed no bony corpuscle pigmentation. Visual function in sectorial retinitis pigmentosa associated with rhodopsin gene codon 15 mutation is on the basis of the rod-cone dystrophy, regardless of differences in phenotypic expression.

Adult↗
PubMed1998

[Inhibitory effects of matrix metalloproteinase inhibitor on corneal neovascularization].

We evaluated the inhibitory effects of matrix metalloproteinase inhibitor (MMPI) on corneal neovascularization in vivo. MMPI drops in the right eye and MMPI basic drops in the left eye were administrated six times per day after wearing a large polymethylmethacrylate-hard contact lens (PMMA-HCL) and intralamellar transplantation of a basic fibroblast growth factor (basic-FGF) containing polymer disk. We observed the status of corneal neovascularization with a slit lamp biomicroscopically after two weeks. Corneal buttons were also investigated histologically with light and electron microscopes. The findings of both investigations showed MMPI eye drops tended to inhibit the corneal neovascularization.

Animals↗
PubMed1998

Homozygotic patient with betaig-h3 gene mutation in granular dystrophy.

PURPOSE: This study investigated patients with granular dystrophy and identified a homozygotic patient and his family with a mutation in the betaig-h3 gene. METHODS: Genomic DNAs were extracted from leukocytes of the peripheral blood of the proband, his parents, and his grandmother. All had granular dystrophy. Genomic DNAs from 50 unrelated normal volunteers were used as controls. Exon 4 of betaig-h3 gene was amplified and analyzed by direct sequence. Clinical data were collected. RESULTS: A single-base-pair transition was detected. This was a substitution of G to A of the second nucleotide position of codon 124 in the betaig-h3 gene that led to a replacement of histidine for arginine (Arg124His, CGC-->CAC). This mutation was the precise one previously reported for Avellino dystrophy. Although the proband was homozygotic for the mutant alleles, his grandmother, and parents were heterozygotic for these alleles. No sequence modification in the codon 124 from 50 nonaffected control individuals was detected. Clinical findings of the proband were severe. Keratectomies were performed for both his eyes 5 times for a 24-year period. His grandmother and parents showed mild clinical symptoms, had a few annular granules in the subepithelial stroma, and maintained good visual acuities. CONCLUSION: Arg124His mutation of the betaig-h3 gene was found in a pedigree with granular dystrophy. This mutation was the precise one previously reported for Avellino dystrophy. This fact shows an existence of Avellino form in Japanese. Homozygotic patient for mutant gene showed severe symptoms and an early onset.

Adolescent↗
PubMed1998

Corneal marginal ulcer in relapsing polychondritis: treatment with keratoepithelioplasty.

This article describes a case of corneal marginal ulcer caused by relapsing polychondritis (RPC) that was treated with keratoepithelioplasty. The patient underwent keratoepithelioplasty with lamellar keratoplasty in the left eye. No relapse occurred in the nasal side in which corneal lenticules were grafted, whereas vascular invasion developed in the temporal side in which no lenticules were grafted. Keratoepithelioplasty was an effective surgical procedure to prevent a recurrence of corneal marginal ulcer in a patient with RPC.

Adult↗
PubMed1998

[Trial of new intraocular lens power calculation following phototherapeutic keratectomy].

We reviewed the SRK-II method and introduce a new equation to calculate the intraocular lens (IOL) power for eyes which underwent laser phototherapeutic keratectomy (PTK). The Gullstrand series was used to determine the power and the radius of curvature of planoconvex IOLs which alter the focal point from the cornea to reach the conjugate point on the retina. The radius of anterior corneal curvature (R), axial length (AXL), predicted postoperative anterior chamber depth (ACD), and lens thickness (LT) were employed in the following formula to calculate the IOL refractive power: K = R/7.7, DC = 337. 5/R, VC = 1,000/DC*1.336 where VC is the posterior vertex focal length. A1 = -(VC-ACD), B1 = AXL-0.5* K-ACD-0. 103 LT, S = 1/A1 + 1/B1; this determined the diopter (D) of IOL in liquid to be (D) = 1,000/(1/S)* 1.336. In eyes which underwent PTK, the keratometric value prior to cataract surgery was not applied. Instead, R' defined as R-dT, where R is the radius of corneal curvature prior to PTK and dT the amount of corneal tissue removed, was introduced. Further, the corneal thickness before cataract surgery (CT') was defined as CT-dT where CT is the corneal thickness prior to PTK. Although it is important to select a lens that has an acurate predicted anterior chamber depth, the new equation appears to be more useful than the SRK-II formula.

Cataract Extraction↗
PubMed1998

[Relationship between visual field loss and retinal nerve fiber layer thickness in open-angle glaucoma].

We studied the correlation between retinal nerve fiber layer thickness and visual field loss in 117 eyes of 62 patients with open angle glaucoma using the Aulhorn Classification as modified by Greve. We divided the peripapillary area into four quadrants [superior (S), inferior (I), temporal (T), nasal (N)] and the total (T0), and measured the peripapillary retinal nerve fiber layer thickness (NFLT) with a confocal scanning laser polarimeter (Nerve Fiber Analyzer). We also obtained the relative ratios (mean ratios) of the total circumference to the nasal quadrant (T0/N), the superior to the nasal quadrant (S/N), the temporal to the nasal quadrant (T/N), the inferior to the nasal quadrant (I/N), the total to the temporal quadrant (T0/T), the superior to the temporal quadrant (S/T), the nasal to the temporal quadrant (N/T), and the inferior to the temporal quadrant (I/T). Significant decreases were observed in the mean ratios to the temporal quadrant, i.e., T0/T, S/T, and I/T, in stages I to VI when compared with stage 0. However, no significant differences were observed among stages I to VI. These results suggest that these parameters may not precisely reflect the progression of the disease, but may aid differential diagnosis of the early stage (stage 0) from the middle and late stages (stages I to VI).

Female↗
PubMed1998

[Relationship between the retinal nerve fiber layer thickness and the effect of aging in normal eyes].

We studied the correlation between the thickness of the retinal nerve fiber layer and the role of age in 155 normal eyes of 83 subjects without significant ocular diseases. Subjects with a refractive error exceeding +/- 5 diopters were excluded. We divided the peripapillary area into four quadrants: superior (S), inferior (I), temporal (T), and nasal (N). We measured peripapillary retinal nerve fiber layer thickness (NFLT) in these four quadrants and in the total area (T(o)) using a confocal scanning laser polarimeter (Nerve Fiber Analyzer), and determined the correlation coefficients. The retinal nerve fiber layer thickness of the total area and of the four quadrants was not significantly associated with an increase in age. Since changes in the thickness were small in the nasal and temporal quadrants, we measured the relative ratios of the thickness in each quadrant to that in the nasal and temporal quadrants. The ratio of the total area to the nasal quadrant (T(o)/N), the superior to the nasal quadrant (S/N), the inferior to the nasal quadrant (I/N), the total area to the temporal quadrant (T(o)/T), the superior to the temporal quadrant (S/T), and the inferior to the temporal quadrant (I/T) was significantly associated with an increase in age. Multiple comparison in each age group revealed no age-related significant decreases in any of the parameters. These findings suggest that these parameters may reflect the degree of aging in normal eyes, but age-related abnormality in the retinal nerve fiber layer thickness may be small.

Adult↗
PubMed1997

FK506-binding proteins regulate smooth muscle contractility by altering neurotransmitter release.

To determine the roles of FK506-binding proteins, receptors for the immunosuppressant FK506, in tachykinin release, we examined the effects of the FK506 derivative ascomycin, [3S-[3R[E(1S,3S,4S)],4S,5R,8S,9E,12R,14R,15S,16R,18S,1 9S,26aR]]-8-ethyl- 5,6,8,11,12,13,14,15,16,17,18,19,24,25,26,26a-hexadecahydro- 5,19-dihydroxy- 3-[2-(4-hydroxy-3-methoxycyclohexyl)-1-methylethenyl]-14,16- dimethoxy- 4,10,12,18-tetramethyl-15,19-epoxy-3H-pyrido[2,1-c][1,4]oxaazacyclotr icosine -1,7,20,21(4H,23H)-tetrone, on the contractility of the rabbit iris sphincter muscle. Ascomycin (10(-7) to 10(-5) M) caused concentration-dependent contractions, which were greatly attenuated by preexposure to rapamycin (10(-5) M), a FK506 receptor antagonist. Similarly, this contractile effect was abolished by preexposure to FK888 (10(-6) M), a tachykinin receptor antagonist, and to capsaicin (10(-5) M), a tachykinin-depleting agent. L-type voltage-dependent Ca2+ channel blockers, nicardipine (10(-5) M) and verapamil (5 x 10(-5) M), inhibited the ascomycin-induced contraction, but the N-type channel blocker omega-conotoxin (10(-6) M) did not. These results suggest that ascomycin stimulates tachykinin release by its binding to FK506-binding proteins and the subsequent activation of L-type Ca2+ channels. Thus, FK506-binding proteins may regulate muscle contractility by altering transmitter release from peripheral tachykininergic nerves.

Animals↗
PubMed1997

A hemizygous A to CC base change of the CHM gene causing choroideremia associated with pinealoma.

BACKGROUND: Although mutations of the CHM gene have been reported in the Caucasian patients with choroideremia, there have been no such reports in non-Caucasian patients. We analyzed the CHM gene in a Japanese patient with choroideremia associated with pinealoma. METHODS: The method for screening was a nonradioisotopic modification of single-strand conformation polymorphism (SSCP) analysis. The PCR products from the patient and the carrier were screened and directly sequenced using an automated DNA sequencer. The PCR product of the carrier was also subcloned into a vector and the subcloned products were sequenced. RESULTS: SSCP analysis showed an identical abnormal band shift in the patient and the carrier. Direct sequence analysis showed a hemizygous A to CC mutation at nucleotide 1608 of the CHM gene in the patient, suspected to result in the absence or truncation of the predicted CHM protein. The sequence using both the PCR product and the subcloned DNA of the carrier showed both wild-type and mutant bands indicating a heterozygote. CONCLUSION: The hemizygous mutation was detected in a patient and the heterozygous pattern in his mother, the carrier, suggesting that this mutation caused the disease.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Effects of the immunosuppressant cyclosporin A on neurotransmitter release from peripheral non-adrenergic, non-cholinergic nerves.

This study was undertaken to determine the effect of the immunosuppressant cyclosporin A on neurotransmitter release from non-adrenergic, non-cholinergic nerves (tachykininergic nerves) in the rabbit iris sphincter muscle. Cumulative application of cyclosporin A (0.1 to 10 microM) caused a slow onset of contraction in a concentration-dependent manner. Both FK888 (1 microM) and capsaicin (10 microM), a substance P receptor antagonist and a substance P-depleting agent, respectively, inhibited the contractile effect of cyclosporin A, whereas atropine (1 microM) had no effect. Both cyclosporin A and capsaicin (10 microM) stimulated the release of substance P-like immunoreactivity in the iris. Neither the sodium channel blocker tetrodotoxin (1 microM), the N-type voltage-dependent Ca2+ channel blocker omega-conotoxin GVIA (1 microM) nor the P-type channel blocker omega-agatoxin IVA (0.2 microM) affected cyclosporin A (1 microM)-induced contraction. In contrast, the L-type Ca2+ channel blocker nicardipine (10 microM) inhibited this contractile effect. These results suggest that cyclosporin A stimulates substance P-like tachykinin release by activating L-type voltage-dependent Ca2+ channels, resulting in contraction of the rabbit iris sphincter muscle.

Animals↗
PubMed1997

The level of erythrocyte aldose reductase is associated with the severity of diabetic retinopathy.

To examine whether the level of erythrocyte aldose reductase is a risk factor for the severity of diabetic retinopathy, the enzyme level in 97 non-insulin-dependent diabetes mellitus (NIDDM) patients was measured by the two-site enzyme-linked immunosorbent assay. Based on the results of fundus photography and biomicroscopy, the severity of retinopathy was classified among NIDDM patients of more than 10 years. The level of erythrocyte aldose reductase was significantly higher in the patients with active proliferative retinopathy than in those with nonproliferative or quiescent proliferative retinopathy. Multivariate logistic regression analysis demonstrated that the level of erythrocyte aldose reductase was an independent risk factor for active proliferative retinopathy (odds ratio, 1.28; 95% confidence interval, 1.01-1.61). The results suggest that a high level of erythrocyte aldose reductase in NIDDM patients may affect the prognosis of diabetic retinopathy. Patients with high enzyme levels would need to be closely followed up in the management of the retinal complication.

Adult↗
PubMed1997

Effect of topical tranilast and corticosteroids on subepithelial haze after photorefractive keratectomy in rabbits.

BACKGROUND: Tranilast (trade name Rizaben), an anti-allergic drug with anti-inflammatory effects, is thought to inhibit synthesis of extracellular matrix of fibroblasts through the suppression of TGF-beta. We evaluated the effect of topical tranilast on the subepithelial haze that developed after excimer laser keratectomy and its effect was compared with that of betamethasone eye drops METHODS: Excimer laser keratectomy (phototherapeutic keratectomy mode) was performed with the Nidek EC-5000 excimer laser on 16 rabbit corneas (eight rabbits). From the second postoperative day, topical 2% tranilast was instilled in the right eye and the control solution in the left eye, four times daily. Until the fourth week after the operation, we measured the densitometric values of scattered light intensity of the subepithelial haze with an anterior ocular analyzer, EAS-1000 (Nidek). At the fifth postoperative week, light and electron microscopy and immunohistochemistry with an antibody to TGF-beta were also performed. RESULTS: Densitometric values of the subepithelial haze in the corneas treated with 2% tranilast were slightly less than those of the subepithelial haze in the control corneas. However, the values of the subepithelial haze in the betamethasone-treated corneas were significantly less than those in control corneas. Histochemical examinations revealed that topical tranilast had a small effect on the subepithelial haze after excimer laser keratectomy in rabbits. CONCLUSION: Topical 0.1% betamethasone can limit the amount of subepithelial haze and tranilast may inhibit development of subepithelial haze by the suppression of TGF-beta.

Administration, Topical↗
PubMed1997

[Thoracic epidural anesthesia for cholecystectomy in a patient after Fontan procedure].

A 12 year-old boy who had received modified Fontan procedure was scheduled for cholecystectomy. Anesthesia was maintained with thoracic epidural anesthesia (Th8-9) and O2-N2O-sevoflurane under mechanical ventilation through the endotracheal tube. Transeshophageal echo cardiography and mixed venous oxygen saturation (SvO2) were used for hemodynamic monitoring. The combined use of epidural anesthesia and volatile anesthetics decreased central venous pressure, left ventricular end diastolic volume, left ventricular ejection fraction and SvO2. These hemodynamic problems were easily solved by infusion therapy and a low dose of dopamine. On the other hand, there were also some hemodynamic benefits such as inhibition of tachycardia and suppression of an increase in pulmonary vascular resistance due to surgical stress. Moreover, patient returned to normal spontaneous breathing with complete analgesia during the early phase after surgery. CVP and SvO2 increased to preoperative values in the recovery room. From these results, we conclude that satisfactory results can be obtained with epidural anesthesia for upper abdominal surgery after Fontan procedure.

Anesthesia, Epidural↗
PubMed1997

Adsorption of levocabastine eye drops by soft contact lenses and its effects in rabbit eyes.

PURPOSE: We evaluated the adsorption of levocabastine (LEV) eye drops onto soft contact lenses in rabbit eyes to confirm the safety of this antihistaminic and antiallergic agent. METHODS: Low- and high- water-content soft contact lenses were placed on the eyes of three rabbits for each type of soft contact lens (total: six rabbits) for 8 hours daily. LEV eye drops and physiological saline solution (used as a control) were instilled into the experimental eye and the fellow eye at a dosage of 0.1 mL per eye, at 1 hour intervals, eight times daily, for 6 consecutive days. Severity of possible eye injury was evaluated before soft contact lens insertion and after removal. RESULTS: After completion of the study, the amounts of LEV and the preservative benzalkonium chloride (BAK) adsorbed onto the soft contact lenses were assayed using high-performance liquid chromatography. There were no significant differences between the experimental solution and the control solution using Draize's method scores or slit lamp evaluation. CONCLUSION: LEV and BAK accumulated only slightly in the soft contact lenses, leading us to conclude that LEV eye drops could be used safely by soft contact lens wearers for about 1 week.

Adsorption↗
PubMed1997

[The ultrastructure of lens capsule abnormalities in Alport's syndrome].

The ultrastructure of lens capsule abnormalities in Alport's syndrome is reported. An anterior lens capsule from a 29-year-old patient with lenticonus who was affected by Alport's syndrome was obtained at phacoemulsification. The histopathological findings showed decreased thickness of the anterior lens capsule and there were many vertical capsular dehiscences localized at the inner part of the lens capsule. Almost every dehiscence was limited to the inner two-thirds of the capsule. One should be cautious in attempting intraocular lens implantation into the lens capsule, since the lens capsule may be fragile in this disease.

Adult↗
PubMed1997

[Correlation analysis between visual acuity and sitting postural parameters of young students].

The relationship between failing eyesight and the sitting posture of young students while studying was studied quantitatively. Among the 19 students who participated in this study, 9 were classified as emmetropic and 10 were myopic. The mean age was 13.2 +/- 2.2 (mean +/- standard deviation) years. Viewing distance, neck angle, viewing angle, vertical gaze direction, and ocular surface area while studying were measured from the lateral and frontal view images of video recordings of the posture. Viewing distance, accommodative power, neck angle, viewing angle, near point, and log transformed visual acuity showed significant differences between these two groups (p < 0.001). Viewing distance of myopes (15.0 +/- 1.9 cm) (mean +/- standard desviation) is shorter than that of emmetropes (30.2 +/- 4.1 cm). Accommodative power of myopes was lower than that of emmetropes. Correlation analysis revealed that the viewing distance of students significantly correlates to neck angle, viewing angle, accommodative power, near point, and visual acuity (p < 0.01). It can be surmised that the failing eyesight of young students results from postural problems such as shortness of viewing distance and increased neck flexion.

Accommodation, Ocular↗