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Biomedical subjects

T Amemiya

Publications and source records attributed to T Amemiya.

At least 91 records · Page 5Linked to original sources
PubMed1997

Metastasis of breast carcinoma to eyelid and orbit of a postmenopausal woman: good response to tamoxifen therapy.

We report a case of metastatic eyelid and orbital carcinoma in a postmenopausal woman 8 years after mastectomy for cancer. MRI scan T1-weighted images with fat suppression revealed an intraconal lesion surrounding the left optic nerve in addition to the left lid tumor. Excision biopsy demonstrated tumor cells in an Indian file pattern. We diagnosed metastasis of breast carcinoma to the eyelid and orbit. Therapy with tamoxifen reduced eyelid and orbital metastases of carcinoma of the breast. Metastatic breast carcinoma should be listed as one of the causes of lesions of the eyelids.

Adenocarcinoma↗
PubMed1997

Peptide leukotrienes mediate acetaldehyde-induced bronchial hyper-responsiveness in guinea-pigs.

BACKGROUND: We previously reported that inhaled acetaldehyde, a metabolite of ethanol and a main factor in alcohol-induced asthma, causes bronchial hyper-responsiveness (BHR) in asthmatics. However, the mechanisms are unclear. OBJECTIVE: The purpose of this study was to investigate a role of a peptide leukotriene (LT) in acetaldehyde-induced BHR. METHODS: Effects of LT antagonists, ONO-1078 (0.1-1.0 mg/kg) and ICI-198, 615 (0.03-0.3 mg/kg), on acetaldehyde-induced bronchoconstriction and BHR to inhaled methacholine were examined using a modified Konzett-Rössler method in guinea pigs. RESULTS: Acetaldehyde at 0.8 mg/ml, which failed to induce significant changes in Pao (pressure at the airway opening), enhanced an increase in Pao induced by subsequent inhalations of ascending doses (50-200 micrograms/ml) of methacholine, suggesting a potentiating effect of acetaldehyde on bronchial responsiveness. Although ONO-1078 had no inhibitory effect on bronchoconstriction caused by ascending doses (5.0-20 mg/ml) of acetaldehyde, ONO-1078 and ICI-198, 615 reduced the acetaldehyde-induced BHR. CONCLUSION: Acetaldehyde causes BHR via LT release in guinea-pigs.

Acetaldehyde↗
PubMed1997

[Successful use of fluconazole against semi-invasive--pulmonary aspergillosis].

A 53-year-old man was admitted to the hospital because of productive coughing general malaise, and right-sided chest pain. At 41 years of age he was given a diagnosis of gastric cancer, underwent a and gastrectomy, was treated with anti-cancer drugs. At 49 years of age he suffered from atypical mycobacteriosis and received anti-tuberculosis drugs for 1 year. A chest X-ray film showed infiltrative shadows with a cavity in the right upper lung field. Semi-invasive aspergillosis was diagnosed on the basis of the clinical and radiographic findings, positive sputum cultures, and positive serologic tests. After 8 months of therapy with intravenous and oral fluconazole, no pulmonary aspergillosis was evident. Treatment with fluconazole was effective in this case of semi-invasive aspergillosis.

Antifungal Agents↗
PubMed1996

Electron microscopic study of optic nerves of macular mice.

The optic nerve of the macular mouse as a model of Menkes' disease was examined by electron microscopy. Since hemizygote macular mice die at 14 or 15 days of age, they were treated with 50 micrograms CuCl2 per 0.1 ml distilled water at 7 days of age. The optic nerves of 1-month-old hemizygote macular mice treated with copper showed hypomyelination and unmyelinated axons, while 1-month-old heterozygote macular mice had focal demyelination of axons. The number of myelinated axons in treated hemizygotes and heterozygotes was statistically significantly lower than that in the control littermates. Oligodendrocytes form myelin sheaths. Since oligodendrocytes of the hemizygote macular mice may have lower activities of cuproenzymes, such as cytochrome oxidase and superoxide dismutase, hypomyelination is assumed to be caused by the dysfunction of oligodendrocyte.

Animals↗
PubMed1996

Electron microscopic study of retinas of macular mice.

BACKGROUND: Menkes' disease may be due to a lack or deficiency of copper in various organs. The macular mouse is known as a model for Menkes' disease. We examined melanin granules in the retinal pigment epithelium and the activity of cytochrome oxidase, a copper-containing enzyme, in the retinas of macular mice by electron microscopy. METHODS: In the retinas of hemizygote macular mice we demonstrated cytochemically (oxidative polymerization of diaminobenzidine to an osmophilic reaction product) the activity of cytochrome oxidase. The distribution of melanin granules in the retinal pigment epithelium related to the activity of another copper-containing enzyme, tyrosinase was also studied. Stereological methods were applied to obtain quantitative data. RESULTS: In the retinal photoreceptor inner segments of the macular mouse, the mitochondria were more numerous than in normal litermates and they appeared swollen. There were fewer melanin granules in the retinal pigment epithelium of macular mice than in that of normal littermates. The cytochrome oxidase activity was significantly lower in the macular mice than in the controls. CONCLUSION: Macular mice have lower activity of cytochrome oxidase and fewer melanin granules than do normal mice. Both changes may be related to copper deficiency. These results correspond to the retinal changes seen in patients with Menkes' disease.

Animals↗
PubMed1996

Immunohistochemical localization of basic fibroblast growth factor, platelet derived growth factor, transforming growth factor-beta and tumor necrosis factor-alpha in the pterygium.

Some fibroangiogenic factors have recently been shown to play potential roles in fibrovascular diseases. The aim of this study was to examine whether there is any relationship between growth factors and pterygium genesis. Twenty-three primary pterygia and 4 normal conjunctiva specimens were analyzed by indirect immunohistochemistry using specific antibodies against basic fibroblast growth factor (b-FGF), platelet derived growth factor (PDGF), transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha). Positive immunostaining of these growth factors was located in the epithelial cells, endothelial cells of vessels, basement membranes of vessels and epithelium, fibroblasts and infiltrating inflammatory cells in the pterygium. In the normal conjunctiva, positive immunolabeling for TGF-beta and PDGF was much weaker than in the pterygium. We conclude that growth factors may interact directly or indirectly in the pathogenesis of pterygium although proof of this awaits further studies.

Antibodies, Monoclonal↗
PubMed1996

Histologic study of living response to artificially synthesized hydroxyapatite implant: 1-year follow-up.

We implanted artificially synthesized hydroxyapatite spheres into the orbits of 13 rabbits after enucleation. The spheres were removed 1, 2, 3, 6, and 12 months after implantation and examined by light and scanning electron microscopy. Tissue breakdown and exposure of the artificially synthesized hydroxyapatite implants were not observed. Month after month, fibrovascular tissues gradually invaded the pores of the artificially synthesized hydroxyapatite spheres deeper and deeper. Although the hydroxyapatite we used was completely artificially synthesized, we observed a mild foreign-body reaction around the artificially synthesized hydroxyapatite spheres. After 12 months, however, relief of the foreign-body reaction had occurred. Hydroxyapatite spheres for orbital implants after enucleation without scleral enveloping are appropriate.

Animals↗
PubMed1996

Involvement of NK2 receptors rather than NK1 receptors in bronchial hyperresponsiveness induced by allergic reaction in guinea-pigs.

1. In this study, the role of neuropeptides in antigen-induced bronchoconstriction and bronchial responsiveness in guinea-pigs was evaluated by use of phosphoramidon, the inhibitor of neutral endopeptidases (NEP), the NK1 receptor antagonist, FK888, and the dual NK1/NK2 receptor antagonist, FK224. The role of endogenous tachykinins in bronchial hyperresponsiveness induced by inhaled capsaicin was also observed with FK888 and FK224. 2. Allergic bronchoconstriction and bronchial responsiveness was evoked by inhalation of ovalbumin (OA), and increasing doses of methacholine were inhaled at 5-min intervals for 30 min after OA challenge in passively sensitized and artificially ventilated guinea-pigs. Animals were treated with a 30 s inhalation of phosphoramidon (10(-3)M) or saline 10 min before the OA challenge. FK888 (1.0 or 10 mg kg-1) or FK224 (1.0 or 10 mg kg-1) was administered intravenously 5 min before the OA challenge. 3. Treatment with phosphoramidon did not alter the increase in the lateral pressure at the tracheal tube (Pao) caused by OA inhalation or the increase in bronchial response to methacholine following the allergic reaction. Pretreatment with FK224 did not inhibit the increase in Pao after antigen provocation but did significantly inhibit antigen-induced bronchial hyperresponsiveness in a dose-dependent manner, while FK888 did not affect either allergic bronchoconstriction or post-allergic bronchial hyperresponsiveness. 4. Histamine, 25, 50, 100 or 200 micrograms ml-1 was inhaled for 20 s at 5-min intervals in non-sensitized guinea-pigs which were pretreated with inhalation of subthreshold dose of capsaicin (10(-7) M). FK888 or FK224, each at a dose of 0.1 or 1.0 mg kg-1, or vehicle was given to guinea-pigs intravenously 3 min before inhalation of capsaicin. The capsaicin inhalation significantly potentiated bronchial responsiveness to histamine, compared with control. The capsaicin-induced bronchial hyperresponsiveness was completely blocked by FK224 in a dose-dependent manner but not by FK888. 5. These results suggest that NK2 receptors rather than NK1 receptors may play an important role in bronchial hyperresponsiveness induced by antigen challenge as well as capsaicin while tachykinins do not play a primary role in the acute bronchospasm elicited by antigen challenge in passively sensitized guinea-pigs.

Animals↗
PubMed1996

Ultrastructure of retina of manganese-deficient rats.

PURPOSE: To elucidate some biologic functions of manganese in the retina. METHODS: Three-week-old weanling Wistar Kyoto rats were used. Manganese-deficient rats were fed a manganese-deficient solid diet containing 0.23 mg manganese/100 g diet and all other nutrients. Control rats were fed a solid diet with 2.9 mg manganese/100 g diet. The retinas were examined by electron microscopy in the 12th, 18th, and 30th months of experimentation. RESULTS: There was a statistically significant decrease in the plasma manganese levels in manganese-deficient animals compared to controls. In rats fed a manganese-deficient diet for 12 months, photoreceptor cells showed karyopyknosis-like changes of nuclei and a decrease in size and number of outer segments. Rats fed a manganese-deficient diet for 18 months showed a complete loss of photoreceptor cells, and the inner nuclear layer nuclei came in direct contact with the retinal pigment epithelium. Rats with manganese deficiency of 30 months showed invasion by capillaries and processes of Müller-like cells from the sensory retina into the retinal pigment epithelium. In the sensory retina, Müller-like cells proliferated, and neural cells disappeared. CONCLUSIONS: Because manganese is related to Mn superoxide in the mitochondrial matrix and to protein and glycogen metabolism, manganese deficiency may disturb the renewal of photoreceptor outer segment discs, and the decrease in antioxidant action caused by a lower level of Mn superoxide dismutase may accelerate the damage to photoreceptor cells. After neural cell loss, Müller-like cells may proliferate. Manganese appears to be essential for maintaining photoreceptor cells.

Animals↗
PubMed1995

Circadian rhythm in the retinal pigment epithelium related to vitamin B12.

The wake-sleep rhythm is a typical circadian rhythm. It has been reported that severely disturbed wake-sleep rhythms are improved by the administration of vitamin B12. This study was designed to clarify whether vitamin B12 is universally related to the circadian rhythm. Three-week-old male Wistar Kyoto rats were fed a vitamin B12 deficient diet for 3 months. Then some of them were given intraperitoneal injections of vitamin B12. We counted phagocytized lamellar structures in the retinal pigment epithelium after the start of exposure to light in negative electron microscopic films. In vitamin B12 deficient rats, the maximum number of phagocytized lamellar structures in the retinal pigment epithelium appeared 3 hours after the start of light exposure, while in the control and vitamin B12 injected groups the peak occurred at 2 hours. This difference suggests that the retinal circadian rhythm is closely related to the level of vitamin B12.

Animals↗
PubMed1995

Corrosion cast demonstration of retinal vasculature of normal Wistar-Kyoto rats.

Plastic corrosion casts of the rat retinal vasculature were studied by scanning electron microscopy. This technique demonstrated the entire retinal vasculature of the rat. The retinal blood vessels supplying the rat's retina have a definite and fairly constant pattern. At the disk there are usually six main artery and vein branches that run symmetrically towards the periphery. Veins are wider and more tortuous. The characteristic arrangement of endothelial cell nuclear indentations clearly differentiates arteries from veins. Retinal arteries have side-arm and dichotomous branchings. The number of vessel branches is greater on the nasal side than on the temporal side of the retina. The vein-over-artery crossing phenomenon is more frequent than the artery-over-vein. Retinal capillaries appear tortuous and are arranged cylindrically in two layers. The superficial network of capillaries comes essentially from arterioles, while deep layer capillary networks are more regularly and densely arranged and are mainly connected with venules. The inner and the outer capillary networks have interconnections, vertical runs and short vascular bridges. Within the retina there are regional variations in capillary pattern and distribution. More regular, dense and rich capillary networks are observed in the peripheral area than at the posterior pole area. No arteriovenous shunts were seen. The study of such plastic casts makes possible a more accurate assessment of some aspects of vascular abnormalities. These findings will be helpful in further investigations of retinal vascular abnormalities.

Animals↗
PubMed1995

Retinal vascular changes during aging in Wistar Kyoto rats. Application of corrosion cast and scanning electron microscopy.

Retinal vasculature changes during aging in normal Wistar Kyoto rats maintained to longevity without known diseases were studied by corrosion casts and scanning electron microscopy (SEM). Six-month-old rat retina showed regular running and arrangement of retinal blood vessels. In 18-month-old rats, a definite morphological change was moderate tortuosity of the vessels, especially at the posterior pole of the retina. In 24-month-old rats, the retinal arteries and veins were very tortuous and narrow, and their calibers were irregular. In some animals occlusion of the veins and localized constriction of the arteries and veins were evident in the vascular casts. Neither arteriovenous crossing defects nor microaneurysms were seen. Retinal capillaries showed marked changes: localized narrowing, constriction, bead-like features, caliber irregularity and occlusion. The corrosion cast method with SEM can demonstrate the details of the capillary networks in the rat retina. The findings demonstrated appear to be related to aging.

Aging↗
PubMed1995

[A case of chronic persistent cough caused by gastro-esophageal reflux].

Although gastro-esophageal reflux (GER) is one of the major causes of chronic persistent cough (CPC) in the USA and in Europe, it is a rare cause of CPC in Japan. We report a rare case of CPC caused by GER, in which treatment with an H2-blocker or with a proton pump inhibitor was successful. A 65-year-old woman had complained of coughing for over 25 years. Her coughing was not alleviated by treatment with a bronchodilator (beta 2-adrenoceptor agonist), an anti-allergic agent, a corticosteroid, or a sedative. GER was considered as a possible cause of her coughing because exacerbation of the coughing was associated with the development of gastrointestinal symptoms (heartburn). Fiberoptic esophagoscopy showed esophagitis and esophageal herniation of the sliding type. Twenty four-hour monitoring of distal esophageal pH showed that the coughing occurred when the pH dropped below 4, and that the pH was less than 4 for about 7% of the whole monitoring time. An H2-blocker or a proton pump inhibitor completely eliminated the symptoms. Therefore, CPC caused by GER was diagnosed. We found that coughing could be induced by instillation of 0.1 N hydrochloric acid at the distal esophagus, and that the coughing was partially inhibited by inhalation of an anti-muscarinic agent (ipratropium bromide) and by esophageal instillation of 4% xylocaine. These data support the "reflex theory". Although CPC caused by GER is rare in Japan, we should remember that GER can be a cause of CPC even in Japanese patients.

Aged↗
PubMed1995

[A study of living response to artificially synthesized hydroxyapatite implant in the rabbit orbit].

We implanted artificially synthesized hydroxyapatite (a-HA) spheres into the orbits of sixteen rabbits after enucleation. The spheres were removed 1, 2, 3, and 6 months after implantation and examined by light and scanning electron microscopy. Tissue breakdown and exposure of a-HA implants were not observed in any case. As time passed, fibrovascular tissue gradually invaded the pores of the HA spheres deeper and deeper. Although the HA used was completely artificially, we observed a mild foreign body reaction around the a-HA sphere. HA spheres are appropriate for orbital implants after enucleation without scleral enveloping.

Animals↗