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A Negi

Publications and source records attributed to A Negi.

At least 55 records · Page 3Linked to original sources
PubMed1999

Analysis of transthyretin amyloid fibrils from vitreous samples in familial amyloidotic polyneuropathy (Val30Met).

The aim of the present study was to analyze the forms of wild type and mutated monomeric transthyretin (Val30Met) in the amyloid fibrils of patients with familial amyloidotic polyneuropathy by electrospray ionization mass spectrometry (ESI-MS). The solubility of amyloid fibrils from the vitrectomized samples was examined to determine the appropriate solution for ESI-MS. ESI-MS analysis revealed that heterozygotic Val30Met amyloid fibrils contained 14.6 +/- 7.5% normal TTR. In all samples, 3 different types of variant ATTR could be identified: Full length ATTR, and -57, and -157 (or 156) Da from ATTR Val30Met were found. The two peaks showing -57, and -157 (or 156) Da from ATTR Val30Met corresponded to the -Gly, and -Gly-Pro sequences of ATTR Val30Met from the N-terminal. The results illustrate the heterogeneity of ATTR amyloid deposits and this method may be very useful for analyzing amyloid fibrils in ATTR related amyloidosis.

Aged↗
PubMed1999

Some vagaries of neonatal lumbar epidural anaesthesia.

Regional anaesthesia and analgesia offer unique advantages of reduction in general anaesthesia requirements and the demands on NICU resources while improving the general outcome. We assessed the feasibility of continuous lumbar epidural analgesia in 20 neonates for various major surgical procedures lasting from 60-260 min. The babies were aged 18 h to 34 days. They were born at a gestational age of 31-40 weeks. We had difficulty in passing the epidural catheter from the lumbar route in two patients, so we had to resort to the caudal route. The problems associated with the placement of the catheter from the lumbar route are discussed. The analgesia was provided for up to 72 h. Nineteen of the babies could be extubated in the operating theatre. They were awake but comfortable at the time of extubation. There were no complications due to the technique. Subsequent to this study, epidural analgesia either by lumbar or caudal route has become the routine in our hospital for all major thoraco-abdominal surgical procedures in neonates.

Age Factors↗
PubMed1998

Morphological changes of choriocapillaris in experimentally induced chick myopia.

BACKGROUND: To clarify the mechanism of chorioretinal atrophy, the morphological changes in choriocapillaris (CC) in myopic chick eyes were investigated. METHODS: Form deprivation myopia was induced in 40 chicks by unilateral eyelid suturing. Vascular corrosion casts of the choroidal vasculature were examined with scanning electron microscopy (SEM). Structural changes in CC capillaries were also examined with transmission electron microscopy (TEM). RESULTS: SEM examination of the casts showed that the CC capillaries in the contralateral control eyes formed an extremely dense network with round or oval intercapillary meshes, whereas the capillaries in the myopic eyes were less dense with wider and more irregular intercapillary meshes. As evidenced with morphometrical analysis, CC in the myopic eyes 4 weeks and older exhibited significantly lesser density and capillary diameter and significantly greater center-to-center distance between adjacent intercapillary meshes than in the control eyes. With TEM, most of the capillaries in the myopic eyes were found to be almost devoid of endothelial fenestrations and had narrowed lumina, particularly evident after the 4th week. CONCLUSION: These results suggest that the decreased CC density caused in myopic chick eyes may be due partly to capillary atrophy and partly to overall stretch of the capillary network caused by abnormal enlargement of the myopic eyes.

Animals↗
PubMed1998

Lacquer crack lesions in experimental chick myopia.

BACKGROUND: Lacquer crack lesion (LCL) is a complication of human pathologic myopia, accompanied by loss of retinal pigment epithelium (RPE) and break of Bruch's membrane. The present paper describes comparable lesions occurring in prolonged experimental myopia in the chick. METHODS: Form-deprivation myopia was induced by unilateral eyelid suturing on the 1st day after hatching. Bruch's membrane in NaOH hydrolyzed preparations and vascular corrosion casts of the choroidal vasculature were examined with scanning electron microscopy. Histological changes in the retina and choroid were also examined with light and transmission electron microscopy. RESULTS: Pale and linear lesions were found in the myopic chick eyes at the age of 8 weeks. In the lesion area, Bruch's membrane was totally broken up and the network of choriocapillaries was totally ruptured with highly atrophied marginal capillaries. The retina was continuous, but was depressed to form a groove in the lesion with the apparently intact inner retina and degenerated photoreceptor cells. Attenuated fibroblasts encompassed the outer circumference of the lesion. RPE cells were scattered in the tissue space inside the fibroblastic investment and also in the choroidal stroma without their polarity. CONCLUSION: The formation of LCL was suggested to be a result of passive stretch exerted upon Bruch's membrane and the capillary network due to abnormal enlargement of the myopic eyes. These results may promote further understanding of the mechanism regarding the development of human lacquer cracks.

Animals↗
PubMed1998

Phacoemulsification, intraocular lens implantation, and trabeculotomy to treat pseudoexfoliation syndrome.

PURPOSES: To determine the long-term risk/benefit ratio of phacoemulsification and intraocular lens (IOL) implantation combined with trabeculotomy to manage eyes with pseudoexfoliation syndrome and co-existing cataract. SETTING: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine; Kurihara Eye Clinic; Departments of Ophthalmology, Tenri Hospital, Kumamoto University, and Matsue Red Hospital; Nagata Eye Clinic, Japan. METHODS: This multicenter retrospective study comprised 49 eyes of 36 patients with pseudoexfoliation syndrome and co-existing cataract who had the combined procedure for uncontrolled intraocular pressure (IOP) (> 21 mm Hg) even on antiglaucoma medication. RESULTS: After a mean follow-up of 20.0 months +/- 13.2 (SD), IOP in all 49 eyes was well controlled (< or = 21 mm Hg). Mean IOP at the final examination was 14.6 +/- 2.6 mm Hg on a mean of 0.9 +/- 0.8 glaucoma medications. Complications included an IOP spike in 11 eyes and fibrin exudation in 1 eye. CONCLUSION: Phacoemulsification and IOL implantation combined with trabeculotomy was an effective treatment for patients with pseudoexfoliation syndrome and cataract.

Aged↗
PubMed1998

Lecithin-bound superoxide dismutase in the prevention of neutrophil-induced damage of corneal tissue.

PURPOSE: To evaluate the effects of a lipophilic analog of superoxide dismutase (SOD) in the prevention of polymorphonuclear leukocyte (PMN)-induced damage to corneal epithelial cells in vitro and in bacterial corneal ulcers in vivo. METHODS: Immortalized human corneal epithelial cells (T-HCEC) were cocultured with human PMNs activated with N-formyl-methionyl-leucyl-phenylalanine for 18 hours, after which lactate dehydrogenase (LDH) activity of the supernatant was measured as a marker of cellular damage. The inhibitory effects of lecithin-bound SOD (PC-SOD) and unmodified SOD, as well as PMNs pretreated with anti-CD 18 monoclonal antibody, were compared with untreated control. The retention of each drug on the ocular surface of healthy volunteers was measured by flow cytometry using brush cytology samples. The protective effects of a 0.1% solution of PC-SOD on Pseudomonas aeruginosa corneal infection in guinea pigs were assessed by inflammatory grading scores and histology. RESULTS: Both PC-SOD and SOD effectively suppressed PMN-induced LDH release in T-HCEC in a dose-dependent manner. LDH release was also attenuated when PMNs were pretreated with anti-CD 18 antibodies, suggesting that adhesion molecules were involved in the process. Brush cytology of conjunctival samples showed that PC-SOD was retained longer on the ocular surface compared with unmodified SOD. PC-SOD significantly prevented excessive tissue damage by infiltrating PMNs in P. aeruginosa corneal infection, whereas in control eyes, perforation of the cornea occurred by 6 days. CONCLUSIONS: PC-SOD was effective in attenuating PMN-related tissue damage to corneal tissue both in vitro and in P. aeruginosa infection in guinea pigs.

Animals↗
PubMed1997

Subacute sclerosing panencephalitis and chorioretinitis.

This is a case report of a 10-year-old boy with subacute sclerosing panencephalitis (SSPE). He initially developed visual disturbance and macular degenerative changes of the right eye at the age of 8 years, followed by chorioretinitis of the left eye, and his neurological symptoms deteriorated rapidly from the age of 10 years. He was diagnosed as having SSPE, as judged on cerebrospinal fluid examination for measles virus RNA by reverse transcription-polymerase chain reaction (RT-PCR), at the second stage of Jabbour's classification on admission. Although high intensity lesions were observed in the right occipital and temporal lobes, especially around the optic radiation, on T2-weighted brain MRI before the start of intrathecal interferon-alpha (IFN-alpha) therapy, they had disappeared at about two months after the treatment. Chorioretinitis (and/or macular degeneration) should be considered in the differential diagnosis of SSPE, permitting early IFN therapy.

Child↗
PubMed1997

Influence of the sensory retina on healing of the rabbit retinal pigment epithelium.

PURPOSE: To compare the healing process of the retinal pigment epithelium (RPE) with and without the overlying sensory retina. METHODS: A dome-shaped retinal detachment was created in the pigmented rabbit eye by injecting balanced salt solution into the subretinal space. The detached retina was partially removed with a vitrector; in some eyes, the detached retina was removed completely. RPE about 1.5 mm in diameter was removed from Bruch's membrane and aspirated through the retinal break. All eyes were examined morphologically. RESULTS: Independent of the sensory retina, 4 days postoperatively the RPE wound was covered by immature RPE cells that gradually formed an epithelial-like sheet by 2 weeks postoperatively. In eyes with overlying sensory retina, regenerated RPE cells similar to normal RPE cells formed a monolayer in most areas. The RPE-photoreceptor outer segment interface gradually organized. In eyes with no sensory retina, the regenerated RPE cells were longer, mounded, and their microvilli were shorter and disorganized. The RPE cells were multilayered in some areas and often had a tubuloacinar structure. CONCLUSIONS: The RPE wounds healed rapidly, independent of the presence of the overlying sensory retina, up to 2 weeks after RPE removal. Reconstruction of the RPE monolayer and the apical morphology of regenerated RPE cells were influenced by the sensory retina.

Animals↗
PubMed1997

Cytoplasmic Ca2+ mobilization and Ca(2+)-dependent membrane currents in dispersed bovine ciliary muscle cells.

PURPOSE: The dependence of plasmalemma Ca2+ influx and Ca2+ release from intracellular stores on Ca2+ activated K+ channels of bovine ciliary muscle (CM) cells were examined. METHODS: The nystatin-perforated patch clamp technique for the measurement of membrane currents and a microscope based fura-2 fluorescence imaging of [Ca2+]i were applied to CM cells freshly dissociated with collagenase and identified with smooth muscle-specific alpha-isoactin. RESULTS: At holding voltages (VH) of > -60 mV, CM cells showed spontaneous transient outward currents (STOCs) and caffeine (> 10(-4) M) induced large transient outward currents (ICAF). Both STOCs and ICAF were abolished by tetraethylammonium chloride (10(-3) M) and charybdotoxin (10(-7) M), but not by apamin (10(-6) M), suggesting that both currents are mediated by Ca(2+)-activated K+ channels similar to those with medium (MK) or large (BK-type) conductance. Both STOCs and ICAF were gradually abolished in the nominally Ca(2+)-free and Co(2+)-containing solutions but were resistant to L-type Ca2+ channel blockers, including nicardipine, verapamil and diltiazem and a N-type channel blocker, omega-contoxin. The [Ca2+]i-elevation during high K+ (100 mM)-depolarization was prevented by Ca(2+)-free and Co(2+)-containing solutions but not by nicardipine. CONCLUSIONS: These results suggest that CM cells possess MK or BK type-like Ca(2+)-activated K+ channels and that L-type Ca2+ channels play minor roles for the maintenance of Ca(2+)-dependent responses in contrast to other types of smooth muscle cells.

Actins↗
PubMed1997

Ocular manifestations of familial amyloidotic polyneuropathy type I: long-term follow up.

AIMS: To obtain precise information on ocular manifestations of familial amyloidotic polyneuropathy (FAP) type I, the incidence of five main ocular manifestations--abnormal conjunctival vessels (ACV), keratoconjunctivitis sicca (KCS), pupillary abnormality, vitreous opacity, and glaucoma, were compared through long term follow up. METHODS: Ocular examinations were performed in 37 FAP type I patients (Met30) from once to 12 times over a period of 1 to 12 years and 7 months. RESULTS: The following incidences were observed on initial examination of each patient with FAP: ACV in 75.5%, pupillary abnormalities in 43.2%, KCS in 40.5%, glaucoma in 5.4%, and vitreous opacity in 5.4%. All ocular manifestations increased with the progression of FAP, and the incidence of ACV reached 100% during follow up: this may be helpful in the diagnosis of FAP. CONCLUSION: Since no precise statistical ocular study on FAP with long term follow up has been performed, this report may provide important information to help elucidate the mechanism of the amyloid distributing process in the amyloid targeted organs of FAP and to provide the natural course of ocular manifestations of FAP.

Adult↗
PubMed1997

Orbital pseudotumors: value of short inversion time inversion-recovery MR imaging.

PURPOSE: To evaluate magnetic resonance (MR) signal intensities of orbital pseudotumors on short inversion time inversion-recovery (STIR) images and to predict the effect of treatment. MATERIALS AND METHODS: Sequential MR examinations were performed in 17 patients with orbital pseudotumors, before and after treatment. All patients underwent MR imaging with T1- and T2-weighted spin-echo or fast spin-echo sequences, and STIR sequences with two 0.5-T systems. Quantitatively and qualitatively, the differences in signal intensities among three therapeutic response groups (good, mild, and no responses) were analyzed for each pulse sequence. RESULTS: Quantitatively, both contrast and contrast-to-noise ratio on STIR images corresponded well to the results of response to therapy for all background markers; contrast and contrast-to-noise ratio values in the good response group were the largest, while those in the no response group were the smallest (P < .0001). Qualitatively, the signal intensities of the lesions in the good response group were interpreted as hyperintense to the cerebral cortex in 14 (93%) or 11 (73%) of 15 lesions by two observers, respectively, while in the no response group, both observers assessed 16 (89%) of 18 lesions as hypo- or isointense to the muscle (P < .0001). CONCLUSION: STIR images showed a variety of signal intensities in the lesions, and the signal intensities on the STIR images helped predict the response to the therapy in orbital pseudotumors.

Adult↗
PubMed1997

Trabeculotomy combined with phacoemulsification and implantation of an intraocular lens for the treatment of primary open-angle glaucoma and coexisting cataract.

BACKGROUND AND OBJECTIVE: The authors previously reported the usefulness of trabeculotomy ab externo for the treatment of primary open-angle glaucoma in adult patients. In an attempt to elucidate the long-term risk-to-benefit ratio of this surgical modality in combination with cataract surgery, the authors conducted a retrospective study of the surgical effects and complications of a triple procedure: phacoemulsification, implantation (of an intraocular lens), and trabeculotomy (PIT). PATIENTS AND METHODS: The authors conducted a retrospective study of patients treated with PIT at multiple hospitals. Intraocular pressure (IOP) and visual function data were obtained from patients after PIT as an initial surgical treatment in cases where antiglaucoma medications failed to resolve uncontrolled IOP (higher than 21 mm Hg). Included in this study were 96 eyes of 64 patients with primary open-angle glaucoma and coexisting cataract. The mean follow-up period was 22.6 +/- 14.7 months (range 3-56 months). RESULTS: In 94 (98%) of the 96 eyes, the IOP was well controlled, having achieved a level of 21 mm Hg or lower at the final examinations. The mean preoperative IOP of the 33 eyes that underwent the triple procedure using a single flap method (PIT-I) was 24.3 +/- 3.9 mm Hg, with an average of 2.1 +/- 1.1 medications. At the final examinations, the mean IOP had dropped to 16.0 +/- 1.2 mm Hg, with an average of 1.2 +/- 1.2 medications. The mean preoperative IOP of the 63 eyes that underwent the triple procedure using a double flap method (PIT-II) was 26.2 +/- 6.2 mm Hg, with an average of 1.9 +/- 1.2 medications. At the final examination, the mean IOP for this group was 15.6 +/- 2.9 mm Hg, with an average of 1.0 +/- 0.9 medications. CONCLUSION: The long-term results from this multicenter study showed that the triple procedure, PIT, can be useful and effective as an initial surgical treatment for open-angle glaucoma in glaucoma patients with coexisting cataract.

Adult↗
PubMed1996

Trabeculotomy ab externo, cataract extraction, and intraocular lens implantation: preliminary report.

PURPOSE: To compare the results of a triple procedure using either extracapsular cataract extraction (ECCE) or one of two phacoemulsification techniques combined with trabeculotomy ab externo and intraocular lens (IOL) implantation. SETTING: Kyoto University Hospital, Kyoto, Japan, and Nagata Eye Hospital, Nara, Japan. METHODS: In this comparative study, 25 eyes with primary open-angle glaucoma had ECCE combined with trabeculotomy ab externo and IOL implantation and 22 had the same procedure using phacoemulsification instead of ECCE. Of the eyes that had phacoemulsification, 10 had a single-flap and 12 had a double-flap procedure. RESULTS: All 22 eyes that had phacoemulsification had a postoperative IOP of 21 mm Hg or less, as did all ECCE eyes except 2. Although the self-sealing incision might have caused the higher incidence of IOP spikes in the immediate postoperative period, IOPs in the phacoemulsification groups were lower after 3 months. Results were similar in the single-flap and double-flap phacoemulsification groups. There were no significant complications. CONCLUSION: Cataract extraction by phacoemulsification or ECCE combined with IOL implantation and trabeculotomy ab externo is a safe, effective treatment for patients with coexisting glaucoma and cataract.

Aged↗
PubMed1996

Regional specification of motoneurons along the anterior-posterior axis is independent of the notochord.

Cek8 and low affinity NGF receptor (LNGFR) are expressed at high levels on the chick spinal motoneurons of the brachial and lumbar segments from embryonic day (E) 5 to E7, but weakly on the motoneurons of the non-limb-innervating segments. We determined by means of heterotopic neural tube transplantation, that the expression of these molecules was already intrinsically determined at E2. We used these spatiotemporal specific molecules as markers of motoneuron subpopulations. To analyze how motoneurons acquire regional specification along the anterior-posterior (A-P) axis and in the transverse plane, we observed the expression of these molecules on ectopic motoneurons induced by implanting a supernumerary notochord or floor plate at E2. The ectopic motoneurons induced by the graft obtained from either the thoracic or lumbar segments had the same expression profile as the normal motoneurons at each A-P level. These findings suggest that regional specification of motoneurons, at least of Cek8 and LNGFR expression, is independent of the notochord and the floor plate and that the whole neural tube appears to be committed to differentiate into the motoneuron subtypes along the A-P axis at the operative stages.

Animals↗
PubMed1995

Long-term results of non-filtering surgery for the treatment of primary angle-closure glaucoma.

BACKGROUND: We previously reported the effectiveness of goniosynechialysis and trabeculotomy ab externo for adult-onset glaucoma. In this study, we performed non-filtering surgery on patients with primary angle-closure glaucoma and studied the long-term outcome of this treatment. METHODS: Included in this study were 35 eyes of 25 patients with primary angle-closure glaucoma, each of which had an intraocular pressure greater than 20 mmHg with maximal tolerated antiglaucoma medication, even after laser iridotomy or surgical iridectomy. Of these 35 eyes, 22 underwent trabeculotomy and 13 underwent goniosynechialysis. All patients were followed up for at least 18 months. RESULTS: In 21 (95%) of 22 eyes after trabeculotomy, and in 12 (92%) of 13 eyes after goniosynechialysis, intraocular pressures were well controlled at or below 21 mmHg at the final examination. However, in two of the 21 eyes in which trabeculotomy was a success, and in four of the 12 eyes in which goniosynechialysis was successful, the procedure had to be repeated before adequate control of pressure was achieved. CONCLUSION: Our results show that intraocular pressure in most cases of primary angle-closure glaucoma can be controlled by restructuring of the physiologic aqueous outflow route by means of goniosynechialysis or trabeculotomy, and that filtering surgery is not necessary.

Aged↗
PubMed1995

Antiviral effect of oryzacystatin, a proteinase inhibitor in rice, against herpes simplex virus type 1 in vitro and in vivo.

Oryzacystatin (OC) is the first-described cystatin originating from rice seed; it consists of two molecular species, OC-I and OC-II, which have antiviral action against poliovirus in vitro (H. Kondo, S. Ijiri, K. Abe, H. Maeda, and S. Arai, FEBS Lett. 299:48-50, 1992). In the experiments reported here, we investigated the effects of OC-I and OC-II on the replication of herpes simplex virus type 1 (HSV-1) in vitro and in vivo. HSV-1 was inoculated onto monolayers of monkey kidney epithelial cells (CV-1 cells) at a multiplicity of infection of 0.1 PFU per cell. After adsorption of the virus onto cells, the cultures were incubated in the presence of either OC-I or OC-II in the concentration range of 1.0 to 300 microM, and the supernatant virus yield was quantitated at 24 h. The effective concentration for 90% inhibition of HSV-1 was 14.8 microM, while a cytotoxic effect on CV-1 cells without infection of HSV-1 was not observed below 500 microM OC-I. Therefore, the apparent in vitro chemotherapeutic index was estimated to be more than 33. In the mouse model of HSV-1-induced keratitis and encephalopathy, topical administration of OC-I to the mouse cornea produced a significant decrease in virus production in the cornea (mean virus yields: 3.11 log10 PFU in the treated group and 4.37 log10 PFU in the control group) and significant improvement in survival rates (P = 0.01). The in vivo antiherpetic effect of OC-I was comparable to that of acyclovir, indicating that topical treatment of HSV-1 infection in humans with OC-I might be possible. Our data also suggest the importance of some thiol proteinases, which may be derived from either the host's cells or HSV-1, during the replication process of HSV-1.

Animals↗
PubMed1994

Surgical results of trabeculotomy ab externo for developmental glaucoma.

OBJECTIVE: To elucidate long-term surgical outcome of trabeculotomy ab externo in the treatment of developmental glaucoma. PATIENTS: Included in this retrospective study are 116 eyes of 71 patients with developmental glaucoma. We classified patients into three groups based on their age: congenital (33 eyes), existing before age 2 months; infantile (31 eyes), occurring from ages 2 months to 2 years; and juvenile (52 eyes), age 2 years or older. RESULTS: A life-table analysis showed that the total success probabilities at 5 and 10 years with one or more trabeculotomy ab externo operations were, respectively, 92.5% +/- 2.7% and 76.5% +/- 6.2%. The success probability of patients with congenital glaucoma (60.3% +/- 15.9%) was significantly lower than it was for those with infantile (96.3% +/- 3.6%) or juvenile (76.4% +/- 7.5%) glaucoma (P < .01 for both). CONCLUSIONS: Surgical results of trabeculotomy ab externo remain effective for a long time. Congenital glaucoma has the worst prognosis, and infantile glaucoma has a better prognosis than does juvenile glaucoma.

Adolescent↗