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T Amemiya

Publications and source records attributed to T Amemiya.

At least 37 records · Page 2Linked to original sources
PubMed2001

Applying secondary ion mass spectrometry to the analysis of elements in goblet cells of conjunctiva.

We investigated the location of elements in the goblet cells of rat conjunctiva by analyzing ion images produced by secondary ion mass spectrometry (SIMS) and comparing them with those produced by energy dispersive X-ray analyser (EDX). Conjunctivas of normal Spraque-Dawley rats were quenched in propane prechilled liquid nitrogen. Semi-thin sections were made with a cryo-ultramicrotome, freeze-dried, carbon-coated and observed under a light microscope, SIMS and scanning electron microscope (SEM). In the element analysis by SIMS, images of positive ions were examined with an O2+ primary ion source and images of negative ions with a Ga+ ion source. The same sections were observed and analysed with SEM-EDX. Morphological features and images of elements with SIMS and EDX were compared. Na, Mg, K, and Ca were detected as positive ions and OH, CN, P, S, and Cl as negative ions with SIMS, but C, N, O, Na, Mg, P, S, Cl, K, and Ca were detected with EDX. The spatial resolution of SIMS in element location was higher than that of EDX. Many elements were clearly located in the goblet cells on ion images by SIMS. Element ion images were demonstrated more densely in goblet cells than in other parts within conjunctiva and by SIMS compared to EDX. SIMS is a useful method for the detection of elements and their locations in ocular tissues and cells.

Animals↗
PubMed2001

Improved nonpenetrating trabeculectomy with trabeculotomy.

PURPOSE: To examine surgical effects and complications of improved nonpenetrating trabeculectomy with trabeculotomy in glaucoma patients. METHODS: Glaucoma patients in two medical institutions underwent nonpenetrating trabeculectomy with sinusotomy with or without trabeculotomy, and the results were compared retrospectively in the two groups by evaluation of final intraocular pressure, drug score, and occurrence of postsurgical complications. RESULTS: Of the 63 eyes of 51 patients in this study, 31 were treated with nonpenetrating trabeculectomy with sinusotomy without trabeculotomy and 32 eyes were treated with nonpenetrating trabeculectomy with sinusotomy and trabeculotomy. The mean follow-up period was 17.0 months. The clinical features in both groups were similar in terms of age, presurgical intraocular pressure (P = 0.96), and presurgical drug score. The eyes treated with nonpenetrating trabeculectomy with sinusotomy without trabeculotomy had significantly reduced intraocular pressures from 21.0 +/- 4.3 (mean +/- SD) to 15.8 +/- 6.3 mm Hg (P = 0.0003) and drug scores from 2.4 +/- 1.2 to 1.6 +/- 1.1 without postsurgical complications. The eyes treated with nonpenetrating trabeculectomy with sinusotomy and trabeculotomy had significantly reduced intraocular pressures from 22.3 +/- 7.5 to 12.5 +/- 2.3 mm Hg (P < 0.0001) and drug scores from 2.5 +/- 1.9 to 0.9 +/- 1.3 without postsurgical complications. Thus, the eyes treated with nonpenetrating trabeculectomy with sinusotomy and trabeculotomy had significantly lower intraocular pressures (P = 0.016) and drug scores than did those treated with nonpenetrating trabeculectomy with sinusotomy without trabeculotomy. CONCLUSION: The authors obtained satisfactory results in reducing intraocular pressure by the combination of nonpenetrating trabeculectomy, sinusotomy, and trabeculotomy.

Adult↗
PubMed2001

[Standard values of inter-inner canthal, inter-outer canthal, and inter-pupillary distances in normal Japanese infants and children].

UNLABELLED: PURPOSE AND MATERIALS: We studied inter-inner canthal distance(DIC), inter-outer canthal distance (DOC), and inter-pupillary distance (PD) in 1,006 normal Japanese infants and children to establish the normal ratio of DIC/PD and DOC/DIC for the diagnosis of congenital anomalies such as Waardenburg syndrome. RESULTS: DIC, DOC, and PD increased significantly from one month after birth to 12 years of age. DIC and DOC were stable but PD increased from 13 years of age to 15 years of age in junior high school. The DIC/PD and DOC/DIC averages were 0.61 and 2.73, respectively, one month after birth and 0.63 and 2.69 at three months after birth. On the other hand, DIC/PD and DOC/DIC were stable at 0.55-0.59 and 2.45 from 8 to 15 years of age. CONCLUSION: Since there have been no reports on standard values of DIC, DOC and PD in infants, we established the standard values in this study. These values are expected to be very useful in the diagnosis of neural crest cell migration anomalies, such as Waardenburg syndrome.

Adolescent↗
PubMed2001

Retinal vascular changes and systemic diseases: corrosion cast demonstration.

The purpose of the present study is to clarify the specific retinal vascular changes in rat models of single spontaneous or hereditary systemic diseases. We used Wistar Kyoto (WKy) rats 6 months of age as normal controls, 24-month-old Wistar Kyoto rats in studies of aging, 16-month-old spontaneously hypertensive rats (SHR), 18-month-old rats with inherited hypercholesterolemia (RICO) for arteriosclerosis, and 18-month-old Otsuka Long-Evans Tokushima Fatty (OLETF) rats for diabetes mellitus. Retinal vascular corrosion casts were made and observed with a scanning electron microscope. The retinal vessels were also examined with a transmission electron microscope. Specific changes in the retinal vessels were: narrowing and thin thread-like capillaries in aging; capillary tortuosity, irregularity and narrowing in hypertension; straightening in hypercholesterolemia; and loop formation and microaneurysms in diabetes mellitus. These specific changes in the retinal vessels in each systemic disease can be clearly and easily revealed in a three-dimensional fashion by corrosion casts followed by scanning electron microscopy.

Aging↗
PubMed2001

Corrosion cast demonstration of choroidal vasculature in normal Wistar Kyoto rat.

No previous attempt has been made so to demonstrate the details of the choroid vascularization in the rat. This paper describes the choroidal vascular pattern of the normal Wistar Kyoto rat using the corrosion cast method. 6-month-old normal Wistar Kyoto rats were used. Vascular casts prepared by our previously described technique were observed with a Hitachi S-2360N scanning electron microscope. Corrosion casts of the entire choroidal vasculature showed that the ophthalmic artery branched into two main ciliary arteries: the nasal and temporal arteries, which extend forward to form the iridociliary circle. Further the inferior ciliary artery arises from the temporal ciliary artery. In the posterior eye segment these arteries form four to seven branches supplying the adjacent choriocapillaris. There are different arrangements of choriocapillaris. The larger veins formed four vortex veins, one in each quadrant, draining blood from the anterior region of the choroid or iris. Venous blood from the central region, peripapillary choroid and sometimes optic nerve head is drained by smaller veins, which run more or less directly into the posterior ciliary veins. In conclusion corrosion casts and SEM can show the details of the choroidal vascular architecture. These three-dimensional (3-D) findings of choroidal vessels of the rat are very useful for the study of choroid vascular abnormalities in various pathological conditions.

Animals↗
PubMed2000

Analysis of Galpha protein recognition profiles of angiotensin II receptors using chimeric Galpha proteins.

Receptors with a heptahelical structure initiate signal transduction by interacting with specific Galpha proteins. The aim of this study was to analyze the ability of type 1 (AT1) and type 2 (AT2) angiotensin receptors to recognize the receptor coupling regions of Galpha proteins using our previously described technique (Ikezu, T., Okamoto, T., Komatsuzaki, K., Matsui, T., Martyn, J.A.J., Nishimoto, I., 1996. Negative transactivation of cAMP response element by familial Alzheimer's mutants of APP. EMBO J. 15, 2468-2475; Komatsuzaki, K., Murayama, Y., Giambarella, U., Ogata, E., Seino, S., Nishimoto, I., 1996. A novel system that reports the G-proteins linked to a given receptor: a study of the type 3 somatostatin receptor. FEBS Lett. 406, 165-170). Chimeric Galphas protein constructs, whose receptor binding regions contained sequences from the four major families of Galpha proteins (Galphaq, Galphai, Galpha12, Galphas), were cotransfected with AT1 or AT2 receptors in COS cells, then stimulated with angiotensin II (Ang II). Changes in cellular cAMP were assayed on cell lysates by enzyme immunoassay. In the case of the Galphaq family, cotransfection of AT1 with Galpha11/Galphas, Galpha14/Galphas, Galpha16/Galphas, elicited significant increases in cAMP after agonist stimulation. Confirmatory results were found using an independent [35S]GTPgammaS binding assay. Further examination using chimeric G proteins for Galpha12 proteins and Galphai family proteins provided evidence that the AT1 receptor can recognize sequences from Galpha12, Galphai1/i2, Galphaz, Galphao, while both receptors interacted with Galphai3. These results provide a Galpha protein recognition database for both AT1 and AT2 receptors, which may be important for understanding the full spectrum of cellular responses mediated by the hormone Ang II.

3T3 Cells↗
PubMed2000

Genetically distinct autosomal dominant posterior polar cataract in a four-generation Japanese family.

PURPOSE: To describe the clinical findings of a form of posterior polar cataract in a large Japanese family and to determine whether the posterior polar cataract is causally related to other autosomal dominant cataracts with known genes, chromosomal locations, or both. METHODS: Systemic and ocular histories were obtained and comprehensive ophthalmic examinations were performed in 15 of 37 members of the Japanese family. The posterior polar cataract was transmitted in an autosomal dominant manner through four generations. Although there is some variation in the degree of opacification, the posterior polar cataract in this family is characterized by progressive disk-shaped posterior subcapsular opacities. Genetic linkage analysis was performed with 41 polymorphic microsatellite markers located in chromosomal regions known for linkage to cataracts. Genomic DNA extracted from the 15 individuals was amplified by polymerase chain reaction, the genotype at the marker loci was determined in each family member, and the lod score was calculated at each locus. RESULTS: Significant linkage of the posterior polar cataract was ruled out from the following 10 loci or chromosomal regions: 16q22 and 1p36, to which two forms of autosomal dominant posterior polar cataract have been assigned: 1q21-q25, 2q33-q35, 13cen, 17p13, 17q11-q12, 17q24, 21q22, and 22q, which are the regions responsible for other autosomal dominant congenital cataracts. CONCLUSIONS: This study confirms the genetic heterogeneity of autosomal dominant posterior polar cataracts and demonstrates that the posterior polar cataract in this Japanese family is phenotypically and genetically distinct from previously mapped cataracts.

Adolescent↗
PubMed2000

The eye and nutrition

Purpose: To examine the effect of vitamins and trace elements on ocular tissue.Materials and Methods: Rats or mice were fed diets deficient in the trace elements Zn, Cu, Mn, Se, Mg, and Cr or in vitamins A, B(12), C, and E. In some rats Al and vitamin A were injected in excessive amounts. We studied the conjunctiva, cornea, retina, and optic nerve with a light microscope, transmission and scanning electron microscopes, an energy dispersive X-ray analyzer, and an ion microscope. Histochemical, cytochemical, and immunohistochemical techniques were applied to the pathological specimens.Results: Deficiencies of Zn, Cu, Mn, and vitamins A, C and E caused a loss of goblet cells in the conjunctiva and a prominent decrease of microvilli and microplicae in the conjunctiva and cornea. The elements in the goblet cells were changed in these conditions. In addition, epithelial cells showed poor fibrous development and abnormal distribution of chromatin in the nucleus.Zn, Cu, Mn, and vitamins A and E deficiencies caused photoreceptor cells to degenerate and disappear. Se deficiency reduced the horizontal and amacrine cells. Vitamin B(12) deficiency reduced nerve fibers in the nerve fiber layer of the retina. Mg deficiency induced multifocal necrosis in the retinal pigment epithelium and apoptotic nuclear changes in the photoreceptor cells. Cr deficiency showed abnormal phagocytosis of the photoreceptor outer segment discs in the retinal pigment epithelium. Vitamin B(12) was found to be related to the circadian rhythm in the retina.Deficiencies of Zn, Cu, Mn, and vitamins A, B(12), and E induced degeneration and disappearance of myelin lamellae in the myelinated optic nerve fibers.In hypervitaminosis A, lipid droplets appeared in the retinal pigment epithelium and alcohol dehydrogenase disappeared in the retinal pigment epithelium and photoreceptor outer segments. Excessive Al was toxic to the retina, which showed disappearance of photoreceptor cells. Al deposits were seen in dendrites and neurons in the outer plexiform layer.Zn seemed to be necessary for corneal epithelial cell wound healing.Discussion: Trace elements usually are contained in enzymes, which have many metabolic functions. They are related to synthesis and breakdown of many substances. Some trace elements such as Zn, Cu, Mn, and Se and vitamins including vitamins A, C, and E prevent peroxidation of lipids. Some vitamins have an affinity for specific tissues such as epithelial cells, nerve fibers, and neuronal cells and are needed for cell differentiation, development, and maintenance.Conclusion: Cu, Zn, Mn, Se, Mg, and Cr and vitamins A, B(12), C, and E are necessary for maintenance of cellular structure and metabolism.

Journal Article↗
PubMed2000

No involvement of lipid mediators in a guinea pig model of ultrasonically nebulized distilled water-induced bronchoconstriction.

An inhalation of ultrasonically nebulized distilled water (UNDW) induces bronchoconstriction only in asthmatics, but the mechanism underlying the response is not fully understood. We have reported that bronchoconstriction occurs immediately after UNDW is inhaled 20 min after an antigen challenge in guinea pigs. Our aim was to examine the role of lipid mediators in this response. Passively sensitized guinea pigs were anesthetized and artificially ventilated. A sulfidopeptide leukotriene receptor antagonist, KCA-757, and platelet-activating factor antagonists, Y-24180 and E6123, were administered i.v. 15 min after an aerosolized antigen challenge, and UNDW was inhaled 5 min later. KCA-757, Y-24180, or E6123 did not, significantly alter the UNDW-induced bronchoconstriction. Together with our previous data that thromboxane A2 receptor antagonists did not influence the UNDW-induced bronchoconstriction, the present results suggest that lipid mediators are not involved in the UNDW-induced bronchoconstriction in our guinea pig model.

Animals↗
PubMed2000

An autosomal dominant posterior polar cataract locus maps to human chromosome 20p12-q12.

We assigned the locus for a previously reported new type of autosomal dominant posterior polar cataract (CPP3) to 20p12-q12 by a genome-wide two-point linkage analysis with microsatellite markers. CPP3 is characterized by progressive, disc-shaped, posterior subcapsular opacity. The disease was seen in 10 members of a Japanese family and transmitted in an autosomal dominant fashion through four generations. We obtained a maximum lod score (Zmax) of 3.61 with a recombination fraction (theta) of 0.00 for markers D20S917, D20S885 and D20S874. Haplotype analysis gave the disease gene localization at a 15.7-cM interval between D20S851 and D20S96 loci on chromosome 20p12-q12. Since the BFSP1 that encodes the lens-specific beaded filament structural protein 1 (filensin) has been mapped around the CPP3 region, we performed sequence analysis on its entire coding region. However, no base substitution or deletion was detected in the CPP3 patients. The mapping of the CPP3 locus to 20p12-q12 not only expands our understanding of the genetic heterogeneity in autosomal dominant posterior polar cataracts but also is a clue for the positional cloning of the disease gene.

Base Sequence↗
PubMed2000

Influence of alpha-adrenoceptor blockade on antigen- and propranolol-induced bronchoconstriction in guinea-pigs in vivo.

1. Beta-adrenoceptor antagonists, such as propranolol, can provoke severe bronchoconstriction only in asthmatic subjects. Recently, we developed a guinea-pig model of propranolol-induced bronchoconstriction (PIB) and the purpose of this study was to investigate the role of alpha-adrenergic nerve pathways in this reaction. 2. Phentolamine administered after an antigen challenge did not inhibit PIB; however, its administration before the antigen challenge significantly inhibited the antigen-induced bronchoconstriction and also bronchoconstriction induced by methacholine inhalation. 3. We conclude that the alpha-adrenergic nerve system is not involved in the development of PIB following allergic reaction in our guinea-pig model.

Administration, Inhalation↗
PubMed2000

Cardiopulmonary complications during gastroscopy in patients with chronic respiratory failure undergoing long-term home oxygen therapy.

BACKGROUND AND STUDY AIMS: Gastric ulcer and hemorrhage are major complications in patients with chronic respiratory failure, but upper GI endoscopy tends to be avoided because of possible cardiopulmonary events. This study was designed to evaluate hypoxemia and subsequent cardiac complications during gastroscopic procedures in patients with chronic respiratory failure undergoing long-term home oxygen therapy (LHOT). PATIENTS AND METHODS: Gastroscopy was carried out in 10 patients undergoing LHOT and 10 age-matched control subjects without pulmonary diseases. Oxygen saturation and cardiac arrhythmias before and during gastroscopy were monitored. Patients were given 10 mg intramuscular scopolamine butylbromide and local anesthesia using 100-300 mg lidocaine gel 15 minutes before the procedure. Each patient continued to receive oxygen via a nasal cannula in the same dosage as their daily use. RESULTS: Decrease in oxygen saturation during endoscopic procedure was significantly greater in patients undergoing LHOT (from 95.9+/-0.9 to 93.4+/-1.7%) compared with control subjects (from 96.7+/-0.4 to 96.2+/-0.4%). There was a significant correlation between the degree of hypoxemia and the oxygen dosage required for their daily treatment in the patients (r = 0.727, P<0.02). CONCLUSIONS: These results indicate that the degree of respiratory failure influences the degree of decrease in oxygen saturation during gastroscopy. It is suggested that use of the nasal route for oxygen supply may be one of the major causes of the hypoxemia.

Aged↗
PubMed2000

Bromomalonic-acid-induced transition from trigger wave to big wave in the Belousov-Zhabotinsky reaction

The Marangoni effects on chemical waves in the ferroin-catalyzed Belousov-Zhabotinsky reaction were studied. The main purpose of the present study was to understand the mechanism of the big wave, an accelerative chemical wave involving surface-tension-driven fluid motions. Spatiotemporal variations of surface tension caused by a chemical wave were measured using the Wilhelmy method. The transition from conventional trigger waves to big waves, due to a concentration change of bromomalonic acid, was observed. The strong surface activity of the bromomalonic acid which was responsible for the transition was also observed. It led to an acceleration of the big waves through the Marangoni effect.

Journal Article↗
PubMed2000

Effect of thromboxane synthase inhibitor, CS-518, on propranolol-induced bronchoconstriction in guinea pigs.

Beta-adrenoreceptor antagonists, such as propranolol, can provoke severe bronchoconstriction in asthmatic subjects. Recently we developed an animal model of propranolol-induced bronchoconstriction and investigated the involvement of chemical mediators in this reaction. The purpose of this study was to elucidate the role of thromboxane A2 in the development of propranolol-induced bronchoconstriction after allergic bronchoconstriction. Passively sensitized guinea pigs were anesthetized and treated with diphenhydramine hydrochloride and were then artificially ventilated. Propranolol at a concentration of 10 mg/ml was inhaled 20 min after an aerosolized antigen challenge. A potent and selective thromboxane A2 synthase inhibitor, CS-518, in doses of 0.01, 0.1 and 1 mg/kg and vehicle were administered intravenously 15 min after the antigen challenge. Another study was performed in naive guinea pigs; ascending doses of methacholine (12.5, 25, 50, 100 and 200 microg/ml) were inhaled for 20 sec at 5-min intervals, 10 min after intravenous administration of CS-518. Propranolol inhaled 20 min after the antigen challenge caused bronchoconstriction in sensitized guinea pigs. CS-518 administered 15 min after the antigen challenge significantly inhibited propranolol-induced bronchoconstriction in a dose-dependent manner, while CS-518 did not influence the dose-dependent response to inhaled methacholine in naive guinea pigs. We conclude that thromboxane A2 contributes to the development of propranolol-induced bronchoconstriction following allergic reaction in our guinea pig model.

Adrenergic beta-Antagonists↗
PubMed1999

X-ray microanalysis of melanin granules of retinal pigment epithelium and choroid in hereditary copper deficient mice (macular mice).

The role of trace elements in vivo has not been completely clarified. Trace elements were studied in melanin granules in the retinal pigment epithelium (RPE) and choroid of hereditary copper-deficient macular mice as a model of Menkes' disease. The analysis of elements in these melanin granules was done by new methods: freeze-embedding and an energy dispersive X-ray microanalysis (EDX). We used 14-day- and 1-month-old male hemizygote macular mice for the experiments and normal litter-mates as controls. Melanin granules in RPE and choroid contained sulfur, chloride, calcium, iron, copper and zinc. Calcium and copper were especially abundant in 14-day-old hemizygote macular mice, although there were few melanin granules in their RPE. The fact that copper was most abundant in the melanin granules in the RPE of 14-day-old macular mice suggests that the synthesis of melanin granules in the RPE and choroid of the hemizygote macular mice cannot be completed because of the lower activity of copper-containing enzymes such as tyrosinase and the abnormal copper distribution in various organs. Therefore, the melanin granules in the RPE and choroid of hemizygote macular mice are irregular in shape and few in number. Large amounts of copper concentrated in melanin granules in the RPE and choroid of hemizygote macular mice might induce quantitative abnormalities of trace elements.

Aging↗
PubMed1999

Optic nerve changes in manganese-deficient rats.

In the present study the changes in the optic nerve due to dietary manganese (Mn) deficiency has examined in Wistar Kyoto rats, since there is a lack of information on the significance of manganese in the optic nerve. After 5 months on a Mn-deficient diet, the optic nerve was examined by light and transmission electron microscopy. The serum manganese level of the deficient rats was significantly lower than that of the controls. The light microscopic findings showed significantly fewer myelinated axons in the Mn-deficient rats and Mn-recovery rats than in the control group, and there were obviously more oligodendrocytes in the recovery rats. Ultrastructural findings were: significantly decreased diameters and lamellae of myelinated axons in the optic nerves of the Mn-deficient rats and abnormal mitochondria in the axons. Rats fed a normal diet for 3 months after 5 months on a Mn deficient diet had a normal serum manganese level, but no change in the abnormal morphology of the myelinated axons. It is concluded that the optic nerve needs manganese for the maintenance of its cell structure.

Animals↗
PubMed1999

Pterygium with bulbar conjunctival hemorrhages.

BACKGROUND: This study was carried out to describe the clinical features and electron-microscopic characteristics of the capillaries in pterygium with conjunctival hemorrhage. METHODS: We compared the clinical findings in Japanese and Tunisian primary pterygia and in pterygium with and without bulbar conjunctival hemorrhages. The capillary fine structures of pterygium with bulbar conjunctival hemorrhages were studied by electron microscopy and compared with those without bulbar conjunctival hemorrhages. RESULTS: Conjunctival hemorrhages were noted in 16.4% of Tunisian patients but not in any Japanese patients. The former pterygia were significantly larger, more vascular and more frequently hyperemic than the latter. Pterygia with bulbar conjunctival hemorrhages were more hyperemic than without hemorrhages. Electron microscopy revealed interruptions of the endothelial cells and basement membrane of the capillaries in the pterygia with bulbar conjunctival hemorrhages, with blood cells escaping through the endothelial interruptions. CONCLUSION: Conjunctival hemorrhage in pterygia may be caused by fragility of the endothelial cells and basement membrane in the capillaries, which easily induces hemorrhage when the eyes are irritated by rubbing or by conjunctival foreign bodies. Pterygium with conjunctival hemorrhage is more frequently found in Tunisians than in Japanese.

Adult↗