Biomedical subjects

T Amemiya

Publications and source records attributed to T Amemiya.

At least 73 records · Page 4Linked to original sources

PubMed1998

Cough receptor sensitivity to capsaicin and tartaric acid in patients with Mycoplasma pneumonia.

There has been no detailed study of cough sensitivity during acute lower respiratory infection. The aim of this study was to clarify cough sensitivity in Mycoplasma pneumonia, which is a well known acute lower respiratory infection with persistent nonproductive cough. We examined cough sensitivity to inhaled capsaicin and tartaric acid in both the acute and the convalescent phases of Mycoplasma pneumonia, cell differentials in bronchoalveolar lavage fluid, and pathologic findings of transbronchoscopic bronchial biopsy specimens. Although dry cough was observed in all patients during Mycoplasma pneumonia, cough sensitivity in the acute phase [capsaicin: 19.8 (GSEM, 0.214) microM, tartaric acid: 0.26 (GSEM, 0.356) M] were not enhanced compared with those in both control subjects [capsaicin: 27.9 (GSEM, 1.24) microM, tartaric acid: 0.316 (GSEM, 0.079) M] and patients in the convalescent phase [capsaicin: 15.7 (GSEM, 0.219) microM, tartaric acid: 0.50 (GSEM, 0.326) M] when all symptoms including cough had disappeared. The percentage of lymphocytes and neutrophils in bronchoalveolar lavage fluid BALF was significantly greater than in the control subjects, and lymphocyte-dominant bronchitis was observed in biopsied specimens. We conclude that cough threshold to inhaled capsaicin or tartaric acid was not enhanced during acute Mycoplasma pneumonia with lymphocyte-predominant bronchitis. This is the first report examining cough sensitivity in patients with acute lower respiratory infection with pneumonia.

Adult↗

PubMed1998

Growth factors in cultured pterygium fibroblasts: immunohistochemical and ELISA analysis.

BACKGROUND: In order to study growth factors in the pathogenesis and recurrence of pterygium, we grew pterygium tissues in culture and compared fibroblasts from primary and from recurrent pterygia with reference to the fibroangiogenic growth factors basic fibroblast growth factor (b-FGF), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-beta) and tumor necrosis factor alpha (TNF-alpha). METHODS: We used indirect immunohistochemical procedures against human b-FGF, PDGF, TGF-beta and TNF-alpha. As controls, we used cultured normal human conjunctival fibroblasts. A serum-free conditioned medium (CM) from confluent fibroblasts derived from primary and recurrent explants was assessed by enzyme-linked immunosorbent assay to determine the level of the above-mentioned growth factors. RESULTS: Immunoreactivity of b-FGF was stronger in recurrent than in primary pterygium fibroblasts. PDGF immunolabeling was stronger in primary than in recurrent pterygium fibroblasts. TGF-beta and TNF-alpha immunolabeling was weak in both pterygia. All these growth factors were very sparse in normal conjunctival fibroblasts. Basic-FGF and TGF-beta 1 were found in the CM from both primary and recurrent pterygium, while PDGF and TNF-alpha were not detectable. CONCLUSION: The strong immunoreactivity and the release of b-FGF in cultured fibroblasts of recurrent pterygia suggest that fibroblasts may play an important role in the recurrence of pterygium.

Adult↗

PubMed1998

A partial involvement of histamine in ultrasonically nebulized distilled water-induced bronchoconstriction in guinea-pigs.

1. Inhalation of ultrasonically nebulized distilled water (UNDW) can induce bronchoconstriction only in asthmatics, but mechanisms of the response are not well known. We recently reported a guinea-pig model of UNDW-induced bronchoconstriction (UNDW-IB) in which UNDW induces bronchoconstriction when UNDW is inhaled 20 min after a challenge with aerosolized ovalbumin (OA) in passively sensitized, anaesthetized and artificially ventilated guinea-pigs. 2. To elucidate the role of histamine in the UNDW-IB, we examined the effects of antihistamines, diphenhydramine hydrochloride (DH) and chlorpheniramine maleate (CP), and measured histamine content in bronchoalveolar lavage fluid (BALF) in the animal model. 3. DH in doses of 0.1, 1.0 and 10 mg kg(-1) and CP in doses of 0.01, 0.1 and 1.0 mg kg(-1) administered intravenously 15 min after the OA challenge partially reduced the UNDW-IB at 1 and 2 min after the UNDW inhalation in a dose-dependent manner. Histamine content in BALF recovered 10 min after the UNDW inhalation following the OA provocation was significantly increased compared with that after saline inhalation and before the UNDW inhalation following the OA challenge. 4. Intravenous atropine in a dose of 0.5 mg kg(-1) or inhaled disodium cromoglycate in concentrations of 1 and 10 mg ml(-1) did not alter the UNDW-IB. 5. These results suggest that histamine is involved in part in the UNDW-IB in our animal model.

Administration, Inhalation↗

PubMed1998

Role of tachykinins in distilled water-induced bronchoconstriction in guinea-pigs.

BACKGROUND: An inhalation of ultrasonically nebulized distilled water (UNDW) induces bronchoconstriction only in asthmatics, but the mechanism underlying the response is not fully understood. We recently showed that bronchoconstriction occurs immediately after UNDW is inhaled 20min after an aerosolized antigen challenge in passively sensitized guinea-pigs. OBJECTIVE: This study was conducted to examine the role of tachykinins in this response. METHODS: Passively sensitized animals were anaesthetized and artificially ventilated, and changes in pressure at the airway opening (Pao) were measured as an overall index of airway narrowing. A tachykinin NK1 and NK2 dual receptor antagonist, FK224, and a tachykinin NK1 selective antagonist, FK888, were intravenously administered 15 min after the antigen challenge. The effects of capsaicin desensitization and a neutral endopeptidase inhibitor, phosphoramidon, were also examined. RESULTS: FK224 and FK888 significantly (P < 0.05 and P < 0.05, respectively) reduced the time course curve of the increase in Pao caused by UNDW inhalation in a dose-dependent manner. The percentage increase in Pao from the preantigen challenge value at 1 min after the UNDW inhalation was 267.4+/-17.1, 358.0+/-33.7 and 412.4+/-27.6% with 10 mg/kg of FK224, 1.0 mg/kg of FK224 and vehicle, respectively, (P<0.01 between 10 mg/kg of FK224 and vehicle) and the value was 254.4+/-48.5% with 10 mg/kg of FK888, 327.1+/-57.6% with 1.0 mg/kg of FK888 and 418.5+/-39.0% with vehicle, respectively (P < 0.05 between 10 mg/kg of FK888 and vehicle). The capsaicin desensitization, but not phosphoramidon, significantly reduced the UNDW-induced increase in Pao. CONCLUSION: These results suggest that tachykinins, at least substance P, are involved in a part of the UNDW-induced bronchoconstriction in our guinea-pig model.

Animals↗

PubMed1998

TNP-470 (a fungus-derived inhibitor of angiogenesis) reduces proliferation of cultured fibroblasts isolated from primary pterygia: a possible drug therapy for pterygia.

PURPOSE: To study drug therapy for pterygium, especially the effect of a fumagillin analog, TNP-470, a potent anti-angiogenic compound, on the growth of cultured fibroblasts obtained from primary pterygia and normal human conjunctiva. METHODS: Cultured pterygium fibroblasts (PF) were exposed to different concentrations of TNP-470 every other day for 7 days (Treatment A) and to a single dose before 4 days of culture (Treatment B). Human normal conjunctival fibroblasts (HCF) were treated with TNP-470 every other day for 7 days. The cells were observed daily by phase contrast microscopy. Cell proliferation was assessed by counting cells with a hemocytometer. Trypan blue uptake was used to determine cell viability at harvest. RESULTS: TNP-470 induced a significant inhibition of PF and HCF proliferation in a dose-dependent manner (P < .0001). At the lowest dose of TNP-470 (100 pg/ml), the cumulative inhibitory effect of TNP-470 was more potent than the sustained inhibitory effect observed by treatment B in one high dose. Nevertheless, the cytotoxic effect was dose-dependent and more marked after treatment A than after treatment B. After washing out of the drug, partial reversibility was observed at doses lower than 5 mg/ml with a significant increase of viability. HCF were less sensitive to TNP-470 and doses less than 5 mg/ml were not cytotoxic. CONCLUSIONS: TNP-470 appears to have a marked inhibitory effect on PF proliferation, and it may be of considerable value in the prevention of pterygium growth and recurrence.

Aged↗

PubMed1998

Superoxide dismutases in retinal degeneration of WBN/Kob rat.

PURPOSE: To examine the relationship between retinal degeneration and superoxide dismutase (SOD) in the degenerative retina of the WBN/Kob rat. METHODS: The retinas of 4-week-old and 10-month-old WBN/ Kob rats were examined with immunohistochemistry and immunoblotting. Wistar Kyoto rats were used as controls. RESULTS: Retinal degeneration began 4 weeks after birth. Four-week-old WBN/Kob rats showed no manganese superoxide dismutase (Mn-SOD) immunoreactivity in the photoreceptor inner segments or copper-zinc superoxide dismutase (CuZn-SOD) immunoreactivity in the outer nuclear layer or photoreceptor inner segments. Control 4-week-old Wistar Kyoto rats showed positive immunoreactivities at these sites. CONCLUSIONS: The retinal degeneration of WBN/Kob rats begins in the outer retina. The lack of SODs in the outer retina may contribute to retinal degeneration in the WBN/Kob rats.

Animals↗

PubMed1998

Necrotizing bronchial aspergillosis as a cause of hemoptysis in sarcoidosis.

The case history is presented of a patient with recurrent massive hemoptysis caused by necrotizing bronchial aspergillosis associated with sarcoidosis. The involved segments (right IX and X) were resected for treatment of the life-threatening hemoptysis. Histologic examination of the resected specimen confirmed the diagnosis. Necrotizing bronchial aspergillosis is a rare variant form of invasive pulmonary aspergillosis and has not been described previously as a cause of hemoptysis in sarcoidosis.

Aspergillosis↗

PubMed1998

Orbital tumor in acute myeloid leukemia associated with karyotype 46,XX,t(8;21)(q22;q22): a case report.

Orbital tumor formation in acute myeloid leukemia (AML) is rare as an initial symptom. Furthermore, orbital granulocytic sarcoma (myeloid sarcoma) in pediatric patients is uncommon. We describe a 5-year-old Japanese girl with a left orbital mass as an initial symptom of AML, the mass revealed by computed tomography. Peripheral blood and bone marrow pictures and a chromosomal analysis disclosing 46,XX,t(8;21)(q22;q22) showed AML (M2 according to the French-American-British classification). She was treated with antileukemic chemotherapy systemically. Three weeks after the initiation of chemotherapy, the orbital tumor regressed markedly. AML as an initial symptom of the orbital mass should be fully considered in a differential diagnosis, even in the absence of typical leukemic symptoms, and chromosomal analysis and immunophenotypical analysis may explain the pathogenesis of the extramedullary leukemic tumor.

Acute Disease↗

PubMed1998

Choroidal coloboma in two members of a family.

A family with choroidal coloboma is reported. A 43-year-old Japanese woman with choroidal coloboma including the optic disk and extending to the inferior half of the fundus in both eyes had horizontal nystagmus, microcornea and mild cortical cataract in both eyes. Her 40-year-old younger sister had choroidal colobomas in both eyes and also a horizontal nystagmus, microcornea in both eyes and a mature cataract in the left eye. They had no systemic abnormalities. Their parents and 2 younger sisters showed neither ocular nor systemic abnormalities. Choroidal coloboma with iris coloboma has been reported frequently, but familial choroidal coloboma without involvement of the iris and with no systemic abnormalities is rare.

Adult↗

PubMed1998

Lens and retinal changes in the WBN/Kob rat (spontaneously diabetic strain). Electron-microscopic study.

Male WBN/Kob rats represent a spontaneously diabetic strain with hyperglycemia, cataracts, nephropathy, neurophathy, pancreatic fibrosis and hyperlipemia. Cataracts and retinal changes in WBN/Kob rats were examined by light and electron microscopy to evaluate the ocular complications. Lens opacity was present in the posterior subcapsular and center of the anterior cortex of male 14-month-old WBN/Kob rats. Light and transmission electron microscopy showed swelling and irregularity of lens fibers. Scanning electron microscopy revealed that lens fibers were irregular and had many granules and bulging processes of various sizes on the cortical side of the opacified region. The nuclear side of the opacified region showed spongy changes and complete absence of lens fibers. Electron microscopy showed retinal degeneration in the photoreceptor outer segments of 1-month-old male WBN/Kob rats. Light microscopy showed thin outer segments and outer nuclear layers in 5-month-old rats, and electron microscopy revealed severe degeneration in the outer segments. The retinas of 11-month-old rats were thinner; the outer plexiform layer was very thin; the photoreceptor cell nuclei in the outer nuclear layer had decreased to one layer and were almost in contact with the inner nuclear layer nuclei, while the visual cells had disappeared. Retinal degeneration had progressed even further in 14-month-old rats, and very few photoreceptor cell nuclei remained. The retinal capillary lumens were small, and their pericytes had thickened basement membranes. The basement membranes of retinal capillaries from WBN/Kob rats were significantly thicker than those from control Wistar rats (p < 0.0001). Although this rat has spontaneous diabetic features, such as cataracts, its retinal changes look more degenerative.

Animals↗

PubMed1998

Development of emulsion type new vehicle for soft gelatin capsule. I. Selection of surfactants for development of new vehicle and its physicochemical properties.

Screening of surfactants was carried out to develop an oil in water (o/w) emulsion type new vehicle for a soft gelatin capsule (SGC), using polyethyleneglycol 400 (PEG 400) as hydrophilic phase and medium chain triglyceride (Miglyol 810), propyleneglycol dicaprylate (Sefsol 228) or soybean oil as hydrophobic phase (PEG 400: hydrophobic phase: surfactant = 87:10:3) and by means of simple homogenization. Polyoxyethylene (20) cetylether (BC-20TX), which can form homogeneous and viscous white gels using the above hydrophilic and hydrophobic phase combination, was selected as a model surfactant for developing the new vehicle. Using Miglyol 810 as hydrophobic phase, a model new vehicle formulation (PEG 400:water:Miglyol 810: BC-20TX = 77:10:10:3) was prepared, and its physicochemical properties were evaluated. The particle size distribution of the new vehicle, after diluting about 3000 times with water, ranged from about 0.5 to 50 microns. Furthermore, the new vehicle had thixotropic property at room temperature (about 25 degrees C) and temperature-dependent gel-sol transforming property with the transformation temperature of about 37 degrees C. These properties meet the requirement for encapsulation of the new vehicle in SGC and suggest that it can be expected to form the o/w emulsion state in the aqueous environment in the stomach. The rheological properties would also make it advantageous for use in other dosage forms such as suppository, cataplasm or liniment.

Capsules↗

PubMed1998

Low-dose basic fibroblast growth factor and vascular endothelial growth factor for angiogenesis in canine acute hindlimb insufficiency.

Basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have shown strong angiogenetic effects in ischemic animals; however, whether such a beneficial effect could be achieved using low doses remains to be determined. The effects of identical low-level doses of these substances on the creation of collateral circulation in canine acute hind limb insufficiency were evaluated. Anesthetized dogs that had undergone left femoral artery occlusion received 20 microg (2 microg/kg) intravenous boluses of either bFGF or VEGF 3 times at 2-day intervals for the first week only, animals on vehicle saline injection served as controls. All groups, control (n=8), bFGF-treated (n=8), and VEGF-treated (n=6) underwent angiography, blood flow measurement (in ml/min) on the day of ligation (day 0), and at 7, 14 and 28 days, then underwent ischemic limb muscle biopsy at 28 days. Angiogenic-treated groups showed remarkable enhanced collateral circulation at 7 days, which was maintained up to 28 days, and the main collateral source artery of the angiogenic-treated groups dilated by 14 days. Many neovascularized arterioles in specimens of the angiogenic groups were recognized without any tissue edema or necrosis. Even low doses of bFGF or VEGF were enough to augment collateral circulation with no side-effects, and short treatment after acute ischemia was effective. Low-dose bFGF or VEGF may be therapeutical effective options in patients with acute lower limb vascular disease.

Animals↗

PubMed1998

Anticoagulation therapy and ocular surgery.

BACKGROUND AND OBJECTIVE: It is not rare for patients receiving anticoagulant therapy to undergo ocular surgery; however, there are no clear guidelines with reference to the operative management of the eye. This study examines the complications in patients receiving anticoagulant therapy who undergo ocular operations and suggests a management regimen for these patients. PATIENTS AND METHODS: The authors retrospectively analyzed 52 patients receiving anticoagulant therapy who underwent ocular surgery between 1993 and 1995. Data included sex, age, reason for anticoagulant therapy, operative procedure, complication rate, and length of time anticoagulant therapy was stopped or reduced prior to surgery. To show the base-line complication rate at their institution, data of patients not receiving anticoagulation therapy were added. RESULTS: Ticlopidine hydrochloride, an antiplatelet drug, was administered to 24 patients. Warfarin sodium was administered to 8 patients, heparin was administered to 8 patients, and other anticoagulants were administered to 20 patients. There were no significant differences in complications between the groups that stopped or reduced anticoagulant therapy and those that did not, but speech disturbance due to thrombotic complication occurred in 1 of 10 patients in whom ticlopidine hydrochloride was stopped or reduced. Hemorrhagic complications occurred in 50% of those who continued ticlopidine hydrochloride, but in none of those who discontinued it (P = .019). There was a significant difference in hemorrhagic complications after cataract surgery between the phacoemulsification, aspiration, and intraocular lens implantation (PEA + IOL) and the planned extracapsular cataract extraction and intraocular lens implantation (PECCE + IOL) groups that continued the drug (P = .0011). No patients showed visual acuity reduction due to hemorrhagic complications. CONCLUSIONS: To avoid life-threatening systemic complications, one need not always stop anticoagulant therapy before performing only cataract surgery. Cataract surgery in patients receiving ticlopidine hydrochloride should be performed with PEA + IOL via a small sclerocorneal or a corneal incision. In cataract surgery for patients receiving anticoagulant therapy, hemorrhagic complications are more frequent than in patients not receiving anticoagulant therapy.

Adult↗

PubMed1997

In vivo intravascular laser photodynamic therapy in rabbit atherosclerotic lesions using a lateral direction fiber.

BACKGROUND AND OBJECTIVE: This study was performed to evaluate the possibility of inducing regression of atherosclerotic foci by photodynamic therapy (PDT) using hematoporphyrin derivative (HpD). STUDY DESIGN/MATERIALS AND METHODS: Atherosclerotic rabbits were divided into four groups: A (n = 6) and C (n = 6) were given 5 mg/kg of HpD intravenously; Groups B (n = 4) and D (n = 4) were not. Twenty-four hours after HpD administration, the aortae of groups A and B were exposed to 200 mw output argon dye laser beam at 630 nm for 10 minutes; groups C and D were exposed to 400 mw for 5 minutes. Three rabbits from groups A and C and two rabbits from groups B and D were sacrificed immediately after laser photoradiation, being named groups A 0, C 0 and groups B 0, D 0, respectively. Groups A 7, C 7, and Groups B 7, D 7 were sacrificed 7 days after the photoradiation. RESULTS: In groups A 7 and C 7, most intimal cells and endothelial cells had become necrotic and disappeared, and a loss of intima was observed. No such changes were found in groups B 7, D 7. CONCLUSION: The above data suggest that PDT caused effective regression of the atherosclerotic lesions.

Animals↗

PubMed1997

Manganese and copper-zinc superoxide dismutases in the developing rat retina.

To determine whether superoxide dismutases (SODs) may be connected with cellular differentiation in the retina, we studied these enzymes by immunolocalization and immunochemical quantitative analysis in developing rat retinas. Four days after birth, manganese superoxide dismutase (Mn-SOD) and copper-zinc superoxide dismutase (CuZn-SOD) immunoreactivities were observed in the neural retina but not in immature neuroblasts. In 9-day-old rats, Mn-SOD immunoreactivity was located in the ganglion cell layer, inner plexiform layer, some cells of the inner nuclear layer, outer plexiform layer, and photoreceptor inner segments differentiated from immature neuroblasts. CuZn-SOD immunoreactivity was found in the same sites except the photoreceptor inner segments. The immunohistochemical staining in 9-day-old rat retinas was the same as in adult retinas. Our quantitative analysis showed increased SODs when retinal cell differentiation ceased. Our results suggest that the concentration of SODs in retinal neuroblasts is too low that immunoreactivity of SODs cannot be visualized. When the differentiation of retinal neuroblasts progresses, SODs appear to be increased in mature retinal cells to protect them from oxidative stress induced by light exposure when the eyes are open.

Animals↗

PubMed1997

Vascular changes in retinas of spontaneously hypertensive rats demonstrated by corrosion casts.

The changes in the capillary network of the retina in spontaneously hypertensive rats (SHR) were demonstrated by scanning and transmission electron microscopy. Corrosion casts with scanning electron microscopy provided a three-dimensional view of the microvasculature of the rat retina and could detect the conspicuous features of the retinal vasculature in SHR. In general, when hypertension lasted for 6-7 months in SHR, tortuosity of the retinal vessels was noted, and later the SHR retina showed increased tortuosity and generalized narrowing of the vessels, localized constriction of the veins, arteriovenous crossing defects, and marked capillary changes, such as caliber irregularity, narrowing, bead-like capillaries, loop formation and localized obliteration. At a later stage, when the blood pressure had been sustained for a long time, there was marked capillary constriction which first affected the superficial capillary network, then scattered capillary network constriction and finally capillary dropout. Transmission electron microscopy revealed narrow capillary lumina and thin endothelium with scarce cytoplasmic components and damaged pericytes. These morphological changes in the capillary network were probably due to structural damage to the endothelial cells, facilitated possibly by compression of the precapillary arterioles. The severity of these changes was usually proportional to the degree and duration of hypertension. These findings indicate that the retinal capillary changes are probably related to hypertension.

Animals↗

PubMed1997

Parameter estimation and dosage adjustment in the treatment with vancomycin of methicillin-resistant Staphylococcus aureus ocular infections.

The susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) to vancomycin (VC) is excellent, but excessive dosing of VC leads to severe side effects. In this study, we present a way of administration planning for each patient based on personal data. To this end, we employed the Sawchuck-Zaske equation to calculate VC clearance (CL) and volume of distribution (Vd) on the basis of three different plasma concentrations of VC, and we used CL and Vd values as prior information before employing the parameter estimation and dosage adjustment program to treat a patient with postsurgical endophthalmitis caused by MRSA and a patient with acute dacryocystitis also caused by MRSA. They had good remissions without any severe side effects.

Acute Disease↗

PubMed1997

Cavernous sinus thrombosis secondary to abdominal wall abscess.

An 84-year-old Japanese woman had cavernous sinus thrombosis (CST) due to abdominal wall abscess. The diagnosis was delayed because abdominal wall abscess is an unfamiliar cause of CST, but a definite diagnosis was reached with the use of magnetic resonance imaging. We started intravenous antibiotic therapy against gram-positive and gram-negative organisms and the patient responded well, although the diagnosis was delayed.

Abdominal Abscess↗