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Biomedical subjects

A Sawada

Publications and source records attributed to A Sawada.

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

Effects of hypoxia and post-hypoxic recovery on chick retinal pigment epithelium potentials and light-evoked responses in vitro.

PURPOSE: To determine the cellular mechanisms involved in the hypoxia-induced alteration of the retinal pigment epithelium (RPE) potentials and the light-evoked responses of the RPE in chicks. In addition, to determine the mechanisms involved in the recovery of the RPE during the post-hypoxic period. METHODS: In vitro preparations of chick retina-RPE-choroid were studied by potassium-selective microelectrodes placed in the subretinal space. In addition, single-barrel microelectrodes were used to obtain intracellular recordings from the RPE cells. The perfusate was bubbled continuously with 95% oxygen and 5% carbon dioxide for the control condition and replaced by 95% nitrogen and 5% carbon dioxide to induce hypoxia. RESULTS: Hypoxia induced a significant reduction of the trans-tissue potential which was found to result from the depolarization of the apical membrane of the RPE. This depolarization was induced by an increase of subretinal [K+]o. The c-wave was also markedly decreased or abolished during hypoxia. There were two phases of post-hypoxic recovery: an initial small increase in the trans-tissue potential resulting from a basal membrane depolarization followed by an apical membrane hyperpolarization. The trans-tissue potential and the c-wave also were supernormal in two phases during this post-hypoxic period. The c-wave amplitude was temporarily elevated (263.7 +/- 77.4% of pre-hypoxic control) because of the enhanced trans-epithelial c-wave and without a light-evoked decrease in subretinal [K+]o. CONCLUSIONS: The trans-tissue potential and the c-wave were markedly decreased during hypoxia. During the post-hypoxic period, both potential recovered with transient supernormalities in two phases. The results suggested that the hypoxic changes resulted directly from changes of the RPE membranes and indirectly from a change in the subretinal [K+]o but were not mediated by the light-evoked decrease in subretinal [K+]o.

Animals↗
PubMed1998

Three paediatric cases of primary sclerosing cholangitis treated with ursodeoxycholic acid and sulphasalazine.

We present here three paediatric patients with primary sclerosing cholangitis. In case 1, the serum gamma-glutamyl transpeptidase was decreased only temporarily by ursodeoxycholic acid (UDCA) treatment and 34 months later, sulphasalazine was added because of microscopic colitis. The enzyme level decreased with dual therapy. Similarly, in case 3, first diagnosed as autoimmune hepatitis, the transpeptidase levels remained elevated for 18 months during treatment with UDCA, prednisolone and mizoribin. The enzyme decreased only after a diagnosis of primary sclerosing cholangitis complicated with ulcerative colitis was established and sulphasalazine was introduced. Case 2 also had Crohn's colitis and was put on UDCA and sulphasalazine from the start. The enzyme level was normalized within 1 month and has remained normal for the following 5 years. Liver biopsies were analysed repeatedly in these three patients. In case 1, periductal fibrosis remained unchanged while being treated by UDCA. There appeared to be no progression in liver cirrhosis in case 3 while being treated by UDCA, prednisolone, and mizoribin. In case 2, who has been treated with both UDCA and sulphasalazine from the start, periductal fibrosis and portal fibrosis were remarkably improved 45 months later. We suggest that sulphasalazine in addition to UDCA might be a viable treatment for children with primary sclerosing cholangitis.

Adolescent↗
PubMed1998

An image analysis study of cataract development after trabeculectomy with mitomycin C.

We prospectively measured quantitative changes in the crystalline lens after trabeculectomy with mitomycin C. Twenty-four eyes in 24 trabeculectomy cases were consecutively enrolled in the study. The enrollment criteria consisted of: phakic eye, no history of intraocular surgeries and no corneal opacification. The transparency of the lens was measured and analyzed by EAS-1000 preoperatively, then 1 and 3 months postoperatively. Changes occurred primarily in the anterior part of the lens, especially in the anterior subcapsular region. The multivariate regression analysis demonstrated an association of cataract development with age, myopic refraction, difference in preoperative and postoperative IOP and systemic hypertension.

Adult↗
PubMed1998

Vibration acceleration magnitudes of hand-held tools and workpieces.

The magnitudes of the hand-transmitted vibration, 297 hand-held tools and workpieces were measured at workplaces. The tools were used mainly in construction and manufacturing industries. The current standard for the measurement of hand-transmitted vibration has been based on the frequency-weighted acceleration of dominant axis method. According to the proposal of ISO/CD5349-1, the results of measurements (462 points) were recalculated by the method of the frequency-weighted acceleration sum. There is 32% of difference in average value between the acceleration sum and the dominant axis method.

Acceleration↗
PubMed1998

A novel mutation of the down-regulated in adenoma gene in a Japanese case with congential chloride diarrhea. Mutations in brief no. 198. Online.

Congenital chloride diarrhea (CLD) is an autosomal recessive disease characterized by excretion of watery stool with a high chloride content. Pathogenesis of CLD is a deficient absorption of chloride in exchange for bicarbonate in the ileum and the colon. In 1996, it was reported that 36 patients with CLD had mutations in the down-regulated in adenoma (DRA) gene; 32 Finnish patients had a three base deletion (951delGGT), 2 Polish patients had a one base mutation (371AtoT) and 2 Polish patients had a one base deletion (344delT). In this study we analyzed the DRA gene in a Japanese boy patient with CLD and in members of his family. The patient was found to have a two base deletion (TT) at nucleotide 1526-1527 within codon 509 which results in a frameshift leading to a permature stopping at codon 517. The patient was homozygous for the deletion, his parents and brother were heterozygous, and his sister was normal. This is the first case of CLD identified to carry a mutation of the DRA gene in Asia.

Adenoma↗
PubMed1998

Age and increased incidence of "forward bowing" of the iris in normal eyes.

PURPOSE AND METHODS: The incidence of forward bowing of the iris, width of the iridocorneal angle, and distance between the apex of the angle and the scleral spur were studied using high-frequency (50 MHz) ultrasound B-scan images in 90 normal eyes from Japanese volunteers. RESULTS: The incidence of forward bowing of the iris, defined as a 120-micron anterior shifting of the posterior profile of the iris, increased from 0% in subjects under 31 years old to 50% in subjects 71 years of age and older. The iridocorneal angle was significantly narrower and the distance between the apex of the angle and the scleral spur was significantly less in eyes with forward bowing. Of the risk factors (age, axial length, sex, and corneal curvature), age (p = 0.0005) was the most significant risk factor for forward bowing of the iris. CONCLUSION: Forward bowing of the iris is not uncommon in the elderly. Half of the Japanese subjects in this study 71 years of age and older had this condition, even though they had no optic nerve atrophy or elevation in intraocular pressure (IOP) at the time of examination.

Adult↗
PubMed1997

Role of screening for hepatitis C virus in children with malignant disease and who undergo bone marrow transplantation.

BACKGROUND: Children with malignant disease who received multiple blood transfusions before the clinical definition of hepatitis C virus (HCV) require evaluation for HCV infection. STUDY DESIGN AND METHODS: The role of HCV infection in 54 children with primary malignant disease was evaluated in terms of the following aspects: prevalence of HCV infection, distribution of HCV subtype, the benefit of screening of blood donors, and the presence of chronic liver disease. The benefit of screening for HCV in a subset of patients who underwent bone marrow transplantation (BMT) was also evaluated. RESULTS: Seventeen patients (31.4%) of 54 tested were seropositive in a second-generation HCV antibody test. Thirteen patients (24.0%) were also positive for circulating HCV RNA. HCV subtype 1b and HCV subtype 2b were found in six and two patients, respectively. Multiple HCV genotypes were present in two patients. One of these two patients had relatively progressive liver disease. Before the introduction of blood screening with a second-generation HCV antibody test, 15 of 35 patients seroconverted, whereas none of 7 patients seroconverted after the screening was used (p = 0.032). For patients who underwent BMT, the screening drastically decreased the seroconversion rate, from 7 of 11 patients to 0 of 6 (p = 0.016). CONCLUSION: A considerable number of children with primary malignant disease who received multiple blood transfusions became infected by HCV before HCV screening was used. Patients who underwent BMT were at high risk for HCV infection. Screening with a second-generation HCV antibody test has proven to be remarkably beneficial in preventing HCV infection in these children.

Adolescent↗
PubMed1997

The nurse shortage problem in Japan.

This article discusses the serious problem of the shortage of about 50,000 nurses in Japan today. If efficient measures to solve it are not adopted by administrators, it is clear that the shortage will become still more alarming in the future, in a society with more people in advanced years and in which the numbers in the younger generation will decrease from now on. The main factors behind the Japanese nursing labour shortage are, among others: a rapid increase in the number of hospital beds between 1986 and 1989, poor working conditions; and nurses' low social position in their places of work. Behind these factors, there has always been a contempt for the art of nursing in our society. Why has Japanese society made light of nursing? Three points can be identified: traditional discrimination against women; our disregard for a religious mentality; and our short history of hospital nursing. To overcome these problems, we must first of all change fundamentally our sense of values, such as love for one another and compassion. We must now reconstruct a caring culture in our society.

Cultural Characteristics↗
PubMed1997

Progressive retinitis-encephalitis due to ganciclovir-resistant cytomegalovirus associated with aplastic anemia.

A 29-year-old woman with aplastic anemia who complained of visual disturbances and pain in the right eyeball was diagnosed as having cytomegalovirus (CMV) retinitis based upon the characteristic retinal changes and isolation of CMV. She received treatment with ganciclovir (GCV), and the retinitis initially responded for several months. However, the patient was found to have CMV lesions in the left eye followed by neurological symptoms. The CMV isolated just before her death was approximately 20 times more resistant to GCV than that isolated previously, suggesting that the GCV-resistant CMV had developed during the long-term treatment with GCV.

Adult↗
PubMed1997

Appositional angle closure in eyes with narrow angles: an ultrasound biomicroscopic study.

PURPOSE: To demonstrate appositional angle closure using ultrasound biomicroscopy under dark room conditions, to investigate patterns of appositional closure, and to correlate those patterns with the angle topology in eyes with narrow angles. METHODS: Forty-six eyes that met the study criteria, from 46 individuals, were examined by ultrasound biomicroscopy under dark room and illuminated conditions. RESULTS: In 40 of the 46 eyes (87.0%), appositional closure was identified by ultrasound biomicroscopy. Two distinct patterns of angle closure were seen: type B, in which closure starts from the bottom of the angle, and type S, in which closure starts in the vicinity of Schwalbe's line. In type B, the iris root was located closure to the chamber angle than in type S. CONCLUSIONS: Ultrasound biomicroscopy performed under dark room conditions is a useful technique for identifying appositional angle closure in eyes with narrow angles. The topology of the iris root is related to the pattern of the appositional angle closure.

Adult↗
PubMed1997

Use of antifibrosis agents and glaucoma drainage devices in the American and Japanese Glaucoma Societies.

PURPOSE: To investigate practice patterns among glaucoma subspecialists in the American Glaucoma Society (AGS) and the Japanese Glaucoma Society (JGS), regarding use of antifibrosis agents and glaucoma drainage devices. METHODS: An anonymous survey incorporating 10 clinical situations was mailed to all AGS and JGS members in December 1995. RESULTS: Half of the AGS (105 of 210), and JGS (25 of 50) members returned surveys. Most respondents (51-87%) preferred trabeculectomy with adjunctive mitomycin for all 10 clinical situations. Mitomycin concentrations varied from 0.1 to 0.8 mg/ml (range of means for 10 situations 0.31-0.39 mg/ml) and intraoperative application times ranged from 5 s to 7 min (range of means for 10 situations 2.5-4.6 min). Preferences for either no antifibrosis agent (up to 39%) or 5-fluorouracil (up to 29%) were highest in primary trabeculectomy. Thirty-seven percent to 64% of AGS members used glaucoma drainage devices, especially after complicated postsurgical glaucomas (after penetrating keratoplasty, scleral buckling, or pars plana vitrectomy) and in neovascular glaucoma, but few JGS members used them. Large differences between university- and private practice-based AGS members were found only in mitomycin use for primary trabeculectomy (33% vs. 52%, respectively; p = 0.07) and for complicated postsurgical glaucomas (46% vs. 70%, respectively; p = 0.03). CONCLUSIONS: Trabeculectomy with mitomycin was the preferred surgical procedure among AGS and JGS members in the clinical situations surveyed. Mitomycin concentration and time of application varied widely. Many respondents used 5-fluorouracil or no antimetabolite in primary trabeculectomy. Glaucoma drainage devices were widely used for complicated glaucomas in the United States.

Chemotherapy, Adjuvant↗
PubMed1997

Different responsiveness to nitric oxide-cyclic guanosine monophosphate pathway in cholinergic and tachykinergic contractions of the rabbit iris sphincter muscle.

PURPOSE: In the rabbit iris sphincter muscle, sodium nitroprusside (SNP), a nitric oxide (NO) donor, inhibits cholinergic contraction but does not affect tachykinergic contraction in vitro. The objectives of the current study were to clarify the mechanism for the different responsiveness to NO in cholinergic and tachykinergic muscular contractions, and to examine whether the mechanism for NO-induced inhibition of cholinergic muscular contraction is operative in vivo. METHODS: Iris sphincter muscle was dissected from the rabbit eye pretreated with or without endotoxin (lipopolysaccharide, LPS) in vivo. Cyclic guanosine monophosphate (cGMP) content in the iris sphincter muscle was determined by radioimmunoassay. The motor activity of the ring-shaped iris sphincter muscle was measured isometrically. Sodium nitroprusside, carboxy-2-phenyl-4,4,5,5,-tetramethyl-imidazoline-1-oxyl-3-oxide (C-PTIO, a scavenger of NO radicals), and 8-bromo cGMP (a permeable cGMP analogue) were administered between the first and second administrations of carbachol and neurokinin A, both of which had caused sustained contraction in the iris sphincter muscle. RESULTS: Sodium nitroprusside inhibited the contraction of the iris sphincter muscle caused by carbachol but had no effect on the contraction caused by neurokinin A. Application of C-PTIO significantly reduced SNP-induced cGMP accumulation in the muscle, as well as the SNP-induced inhibition of muscular contraction caused by carbachol. Neither carbachol nor neurokinin A influenced SNP-induced cGMP accumulation in the muscle. Induction of 8-bromo-cGMP significantly diminished the muscular contraction caused by carbachol but not that caused by neurokinin A. In vivo pretreatment of the eye with LPS increased, in a time-dependent manner, the cGMP accumulation in the iris sphincter muscle, which was significantly inhibited by pretreatment of NG-nitro-L-arginine methyl ester (an inhibitor of NO synthesis) in vivo. CONCLUSIONS: These results demonstrate that in rabbits the increase in cGMP accumulation induced by NO in the iris sphincter muscle is involved in the cholinergic contraction but not in the tachykinergic contraction, suggesting that different sensitivities to cGMP are essential for the different responsiveness to NO. Furthermore, the results of this study showed that the NO-cGMP pathway is operative in vivo and regulates iris sphincter muscle tone, at least when the eyes are infected with bacteria.

Animals↗
PubMed1997

Appositional angle closure in eyes with narrow angles: comparison between the fellow eyes of acute angle-closure glaucoma and normotensive cases.

PURPOSE: To identify topologic features of eyes with acute primary angle-closure glaucoma before an attack as compared with those features in normotensive cases, assuming that untreated fellow eyes of acute primary angle-closure glaucoma are candidates for an acute attack. METHODS: A total of 50 eyes (12 fellow eyes of acute primary angle-closure glaucoma and 38 normotensive cases with a closure-possible narrow angle) were prospectively examined by ultrasound biomicroscopy under dark-room conditions. All eyes were examined before surgical or laser intervention and had normal pupillary reaction without any topical drugs. Four predetermined angle locations per eye were examined. Parameters regarding the chamber angle configuration were measured and compared between the two groups. RESULTS: Appositional angle closures were observed in 27 locations in fellow eyes and in 48 locations in normotensive eyes with a closure-possible narrow angle. The incidence was statistically different between the two groups (69.2% in the fellow eyes and 48% in the normotensive eyes). Appositional angle closures beginning at the entrance of the angle were more frequently detected in the fellow eye group. The distance between the iris root and the bottom of the angle was significantly different between the two groups. CONCLUSION: The fellow eyes of acute primary angle-closure glaucoma have different topologic features from normotensive narrow-angled eyes and a higher incidence of appositional closure that may predispose these eyes to an imminent acute attack.

Acute Disease↗
PubMed1996

Ultrasound biomicroscopic findings of acute angle-closure glaucoma in Vogt-Koyanagi-Harada syndrome.

PURPOSE: We studied a case of Vogt-Koyanagi-Harada syndrome with transient shallow anterior chamber and increased intraocular pressure as initial manifestations. METHODS: We examined the patient using ultrasound biomicroscopy and speculated on the mechanisms of increased intraocular pressure. RESULTS: Ultrasound biomicroscopic examinations revealed the swollen ciliary body with anterior rotation and supraciliary space at the time of increased intraocular pressure. CONCLUSIONS: We confirmed that the swollen ciliary body with anterior rotation and supraciliary space caused transient angle-closure glaucoma in this patient with Vogt-Koyanagi-Harada syndrome.

Acute Disease↗
PubMed1996

Prevention of visual field defect progression with brovincamine in eyes with normal-tension glaucoma.

PURPOSE: A prospective investigation of the effect of brovincamine fumarate, a Ca2+-channel blocker, on visual field changes in normal-tension glaucoma (NTG). METHODS: A total of 28, age- and field-matched, patients with NTG were allocated randomly to either brovincamine fumarate (20 mg 3 times daily) or placebo (3 times daily). The patients were followed at least every 4 months for a minimum of 2.5 years, and visual field examinations were carried out at least every 6 months. The mean follow-up periods (+/-standard deviation) were 39.1 +/- 8.7 months in the brovincamine-treated group and 37.9 +/- 10.1 months in the placebo group. Stepwise discriminant analyses were performed to separate the patients who showed improvement of their visual fields from those who failed to improve in the brovincamine-treated group, and to identify factors that may determine the visual field prognosis of all patients with NTG enrolled in the study. RESULTS: In the brovincamine-treated group, six patients showed visual field improvement, whereas none showed improvement in the placebo group using the Statpac 2 linear regression analysis. Discriminant analyses identified better cold recovery rate and higher initial systolic blood pressure to be significantly contributory to a favorable outcome in the brovincamine-treated group, and the use of brovincamine, better cold recovery rate, and higher initial systolic blood pressure were identified to be significantly contributory to a favorable prognosis in all subjects. CONCLUSION: Brovincamine seems to have a favorable effect on visual field in at least some patients with NTG.

Administration, Oral↗
PubMed1996

Primary low cerebrospinal fluid pressure syndrome with galactorrhea: findings at MR imaging.

A case of primary low cerebrospinal fluid (CSF) pressure syndrome with galactorrhea is reported. Magnetic resonance imaging demonstrated diffusely enhanced meninges, edematous brain, and enlarged pituitary gland. Coincidental enlargement of pituitary gland and edematous brain due to low CSF pressure compressed the pituitary portal system. The low-perfused anterior lobe of pituitary gland would be the mechanism of galactorrhea.

Adult↗
PubMed1996

Autosomal dominant cone-rod dystrophy associated with a Val200Glu mutation of the peripherin/RDS gene.

OBJECTIVE: Mutations of the peripherin/RDS gene have been reported in several kinds of retinal dystrophy, and they show a variety of manifestations. The authors identified a novel Val200Glu mutation of the peripherin/RDS gene in a Japanese family with autosomal dominant cone-rod dystrophy (CRD). This report describes a genotype-phenotype correlation of the Val200Glu mutation. PATIENTS AND METHODS: Fifteen members of one Japanese family with autosomal dominant CRD were screened for mutations in the peripherin/RDS and ROM 1 genes. Clinical features were identified by visual acuity, visual field testing, fundus examination, and electroretinography. RESULTS: A Val200Glu mutation was found in all of the affected family members examined and was segregated with the disease. No patient had a mutation in the ROM 1 gene. Phenotypic characteristics of each affected member in this family showed intrafamilial similarity. Characteristic features included cone function more severely impaired than rod function and degenerative change in the macular region associated with peripheral retinal degeneration. CONCLUSION: The mutation at codon 200 of the peripherin/RDS gene causes both cone and rod degeneration. The Val200Glu mutation results in a type of autosomal dominant CRD.

Adult↗