Biomedical subjects

S Kishi

Publications and source records attributed to S Kishi.

At least 73 records · Page 4Linked to original sources

PubMed1997

Ciliary detachment after retinal detachment surgery.

PURPOSE: To evaluate the changes in the ciliary body and anterior choroid that occur after retinal detachment surgery. METHODS: Thirty-three eyes with rhegmatogenous retinal detachment were evaluated before and after surgery. An ultrasound biomicroscope was used to observe the ciliary body and anterior choroid. RESULTS: Ciliary detachment was found to be present in 22 eyes (67%) on examination 5-14 days after surgery. The detachment was confined to the pars plana in nine eyes and involved the pars plicata and plana in 13 eyes. The whole circumference of the ciliary body was detached in seven of the 13 eyes. In three of these seven eyes, ophthalmoscopy showed the detachment to extend to the anterior choroid. Ciliary detachment lasted for at least 2 weeks and resolved within 2 months in 19 of 22 eyes. A shallow anterior chamber was observed after surgery in 12 eyes with severe ciliary detachment. Ciliary detachment was more likely to occur in eyes with a large retinal tear, large area of scleral buckling, or in eyes that were treated with solid silicone exoplant. CONCLUSION: Ciliary detachment occurred frequently after retinal detachment surgery using scleral buckling. It was temporary and usually did not result in untoward complications.

Adolescent↗

PubMed1997

Ectopic lacrimal gland of the orbit.

A case of intraorbital ectopic lacrimal gland was evaluated with various radionuclides. CT and MRI with contrast enhancement showed a soft-tissue mass in the orbit. The lesion was gallium-avid, but 18F-FDG PET demonstrated very faint uptake. On early and delayed 201Tl-Cl images, mildly increased uptake and mild retention were observed. Technetium-99m-(V)-DMSA SPECT showed intense accumulation on both the early and delayed images. Technetium-99m-pertechnetate SPECT, demonstrating marked uptake in the lesion, was useful for the differential diagnosis between intraorbital malignancy and this benign lesion. These scintigraphic variations played an important role in the tissue characterization of this uncommon lesion.

Child↗

PubMed1996

Zinc compounds inhibit osteoclast-like cell formation at the earlier stage of rat marrow culture but not osteoclast function.

The effect of zinc compounds on osteoclast-like cell formation in rat marrow culture in vitro was investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone resorbing hormone (1, 25-dihydroxyvitamin D3 and parathyroid hormone [1-34]). Osteoclast-like cell formation was estimated by staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of 1, 25-dihydroxyvitamin D3 (10(-8) M) or parathyroid hormone (PTH; 10(-8) M) induced a remarkable increase in osteoclast-like multinucleated cells (MNC). These increases were clearly inhibited by the presence of zinc sulfate or zinc-chelating dipeptide (beta-alanyl-L-histidinato zinc; AHZ) in the concentration range of 10(-7) to 10(-5) M. The inhibitory effect was seen at the earlier stage of osteoclast-like MNC formation. However, zinc compounds (10(-6) M) did not have an effect on PTH (10(-8) M)-induced osteoclast-like cell formation in the presence of EGTA (5 x 10(-4) M), dibucaine (10(-5) M) or staurosporine (10(-9) M). Moreover, when osteoclasts isolated from rat femoral-diaphyseal tissues were cultured for 24 h in the presence of zinc compounds (10(-7) to 10(-5) M), the compounds did not have an effect on cell numbers or lysosomal enzymes activity (acid phosphatase and beta-glucuronidase) in the cells. The present study clearly demonstrates that zinc compounds inhibit osteoclast-like cell formation at the earlier stage with differentiation of marrow cells.

Acid Phosphatase↗

PubMed1996

The role of the premacular liquefied pocket and premacular vitreous cortex in idiopathic macular hole development.

PURPOSE: To clarify the role of the vitreous in idiopathic macular hole formation. METHODS: We prospectively evaluated the vitreous before and during vitreous surgery in 64 consecutive eyes of 62 patients (stage 1B, four eyes; stage 2, ten eyes; stage 3, 43 eyes; stage 4, four eyes) with macular holes; another three eyes underwent a second vitrectomy. After core vitrectomy, the premacular vitreous cortex was examined by applying gentle suction. The detached posterior hyaloid face was observed under endoilluminiation. RESULTS: We observed in all eyes a liquefied lacuna anterior to the posterior fundus before and during vitreous surgery. The premacular vitreous cortex was extremely thin and elastic upon gentle suction. A premacular ring, the diameter two to four times that of the Weiss ring, was observed in 48 of 57 eyes (84%) with stages 1B, 2, and 3 macular hole. In most cases, the vitreous cortex within the premacular ring either was absent or had a break, resulting in a premacular round defect. The vitreous cortex peripheral to the premacular ring, which was thick and less deformed, never showed a break. In eyes that had undergone a second vitrectomy, we noted residual cortex or an epiretinal membrane around the macular hole. CONCLUSIONS: The premacular vitreous cortex is extremely thin and elastic. It is sharply demarcated by a ring from the thick peripheral vitreous cortex. Tangential traction, which causes macular holes, appears to originate exclusively in the premacular vitreous cortex that forms the posterior wall of the premacular liquefied pocket.

Eye Diseases↗

PubMed1996

Watershed zone in the human peripheral choroid.

PURPOSE: To evaluate the angioarchitecture and the hemodynamics in the peripheral choroid in humans. METHODS: Choroidal circulation was examined in 23 normal eyes and in 7 with equatorial lattice degeneration by wide-angle indocyanine green (ICG) angiography using a scanning laser ophthalmoscope. A hand-held 30-diopter lens was placed in front of the eye to expand the observation angle from the original 40 degrees to 70 degrees. The peripheral temporal choroid and the ora serrata thus could be seen in one frame. RESULTS: An arterial watershed zone was identified in the temporal peripheral choroid in 21 of 30 eyes. This watershed zone was located in a sectorial region posterior to the ora serrata. It did not form a circular belt along the equator. The area anterior to the watershed zone was supplied by peripheral retrograde choroidal arteries. Inflow of dye into the peripheral retrograde choroidal arteries was consistently later than into the more posterior choroid via short posterior ciliary arteries. The terminal branches of peripheral and short posterior ciliary arteries did not form functional anastomoses. Peripheral retrograde choroidal arteries showed wide variations in number and distribution. These arteries originated from recurrent branches of long posterior ciliary arteries in 18 of 21 eyes and from anterior ciliary arteries in 3 eyes. There was no correlation between the watershed zone and equatorial lattice degeneration in location and extent. CONCLUSION: A peripheral watershed zone is a regular feature in the far temporal sector of the choroid. The far peripheral choroid anterior to the watershed zone was perfused by peripheral retrograde choroidal arteries which originated from the long posterior ciliary arteries and/or the anterior ciliary arteries.

Adolescent↗

PubMed1996

[Programmed thymic T cell death and negative selection via Fas and TCR/CD3 complex].

In the immune system of thymic microenvironment, immature T cells are selected by T cell receptor (TCR)-mediated antigen stimulation and most of thymic T cells die by apoptosis. Molecular mechanism for the elimination of autoreactive T cells by apoptotic cell death in thymus is almost unknown, though a differential avidity model for TCR-mediated selection is recently proposed. On the other hand, Fas antigen (Fas), which is apoptosis inducing cell surface receptor, is expressed on antigen stimulated human thymocytes and involved in superantigen-induced negative selection. Recent studies have suggested that CD30 and CD40 ligand (gp39) on thymocytes is also involved in a part of negative selection. Thus, it is likely that the process of negative selection may involve multiple, and to some extent redundant, costimulation signals.

Apoptosis↗

PubMed1996

Membranous nature of premacular vitreous cortex in the human eye.

To characterize the morphologic nature of the premacular vitreous, we examined the posterior vitreous of 24 normal autopsy eyes without posterior vitreous detachment (PVD) by biomicroscopy and scanning electron microscopy (SEM). For biomicroscopic observation, the vitreous was stained with fluorescein and immersed in water. The posterior portion of the eyeball was then desiccated and examined by SEM. The vitreous cortex was extremely thin in the premacular area, and premacular liquefied lacuna was invariably seen in front of the thin vitreous cortex by biomicroscopic observations. In SEM the premacular vitreous cortex appeared to be a cellophane-like membrane overlying the retina at x40 approximately 100 magnification. A meshwork structure could be seen in the cellophane-like membrane at the magnification of approximately x1000. The diameter of fibers in the meshwork was compatible with that of vitreous collagen. We confirmed that the premacular vitreous cortex was of a membranous nature distinct from the vitreous gel in eyes without PVD.

Aged↗

PubMed1996

A multiple gastric ulcer case caused by cytomegalovirus infection.

The patient was a 31 year old male complaining discomfort in the epigastrium. Endoscopy of the upper gastrointestinal tract indicated multiple gastric ulcers. Biopsy specimen taken from the ulcerous region indicated giant cells accompanying intranuclear inclusion bodies in the gastric mucosa. Since the patient tested positive to cytomegalovirus (CMV)-IgM antibody, he was assumed to have gastric ulcers caused by CMV infection. However, the patient was cured without the administration of antiviral agent because no definite immunodeficiency status was observed. The result of present study indicated that endoscopic biopsy is useful for diagnosing gastrointestinal lesion attributable to CMW infection.

Adult↗

PubMed1995

Inhibitory effect of zinc-chelating dipeptide on parathyroid hormone-stimulated osteoclast-like cell formation in mouse marrow cultures: involvement of calcium signaling.

A possible mechanism of zinc action inhibiting the PTH-induced osteoclast-like cell formation in mouse marrow culture system in vitro was investigated. Bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone-resorbing agent parathyroid hormone (1-34) (PTH). Osteoclast-like cell formation was estimated with staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The effect of zinc sulfate (10(-6) M) or beta-alanyl-L-histidinato zinc (AHZ; 10(-6) M) inhibiting the PTH (10(-8) M)-induced osteoclast-like cell formation was clearly seen in the absence or presence of theophylline (10(-4) M). However, zinc compounds did not inhibit the stimulatory effect of dibutyryladenosine 3',5'-cyclic monophosphate (DBcAMP; 10(-4) M) on osteoclast-like cell formation. The stimulating effect of PTH (10(-8) M) on osteoclast-like cell formation was clearly weakened (about 50%) in the presence of EGTA (1.0 mM) or dibucaine (10(-5) M). Phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator (10(-8) to 10(-6) M), clearly stimulated osteoclast-like cell formation. PMA effect was inhibited by the presence of AHZ (10(-6) M) or zinc sulfate (10(-8) M). However, the inhibitory effect of zinc compounds was not seen in the presence of both PTH (10(-8) M) and PMA (10(-6) M). The present findings suggest that zinc compounds inhibit PTH-stimulated osteoclast-like cell formation mediated through the Ca(2+)-dependent activation of protein kinase C.

Animals↗

PubMed1995

Differential effects of transforming growth factor-beta on osteoclast-like cell formation in mouse marrow culture: relation to the effect of zinc-chelating dipeptides.

The effect of transforming growth factor-beta (TGF-beta) on osteoclast-like cell formation in mouse marrow culture in vitro was investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone resorbing agent. Osteoclast-like cell formation was estimated with staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of TGF-beta (10(-13)-10(-11) M) caused a significant increase in the number of osteoclast-like multinucleated cells (MNCs); the maximum effect was seen with 10(-12) MTGF-beta. With a higher concentration (10(-10) M) of TGF-beta, the growth factor dramatically inhibited the 1,25-dihydroxyvitamin D5 [1,25(OH)2D3; 10(-8) M]-induced formation of osteoclast-like MNCs. This inhibitory effect was also seen in the formation of osteoclast-like MNCs stimulated by parathyroid hormone (10(-8) M), prostaglandine E2 (10(-6) M), and interleukin-1 alpha (50 U/ml). The stimulatory effect of TGF-beta (10(-12) M) on osteoclast-like MNCs formation was inhibited by zinc sulfate (10(-6) M) or zinc-chelating dipeptide [beta-alanyl-L-histidinato zinc (AHZ), 10(-6) M]. The stimulating effect of TGF-beta was markedly weakened by the presence of EGTA (0.5 mM), a chelator of Ca2+. The inhibitory effect of zinc compounds was not seen in the presence of EGTA. Moreover, the inhibitory effect of TGF-beta (10(-10) M), zinc sulfate (10(-6) M), or AHZ (10(-6) M) on osteoclast-like MNCs formation was not demonstrated in mature osteoclastic cells, although calcitonin (3 x 10(-8) M) significantly inhibited the osteoclastic formation. The present study demonstrates that TGF-beta has a stimulating and an inhibiting effect on osteoclast-like cell formation in mouse marrow culture, and that zinc can inhibit the stimulatory effect of TGF-beta.

Animals↗

PubMed1995

Tractional elevation of Henle's fiber layer in idiopathic macular holes.

PURPOSE: We sought to clarify the morphologic features of macular hole development. METHODS: Using scanning laser ophthalmoscopy, we examined 47 eyes with macular holes before and after vitrectomy. Cases included three eyes with stage 1B disease (foveal detachment), 14 with stage 2 (break at the fovea), 21 with stage 3 (full-thickness macular hole), and nine with stage 4 (detached operculum), according to Gass's classification. Ten eyes with central serous chorioretinopathy served as controls. RESULTS: Radiating striae of Henle's fibers were seen around the elevated rim of the macular cyst or hole when the intraretinal structures were illuminated by helium-neon laser. Granularity was observed on the macular hole floor. A granular reflex corresponding to the macular break or hole, but no radiating striae were seen by argon blue laser. In 40 eyes in which macular holes were successfully closed by vitrectomy, radiating striae of Henle's fiber layer disappeared, and the normal foveal depression was restored. The ten eyes with central serous chorioretinopathy had a normal foveolar depression and no detectable radiating striae of Henle's fiber layer, despite full-thickness retinal detachment in the macular area. CONCLUSIONS: Tractional elevation of Henle's fiber layer with intraretinal foveolar cyst formation is the initial feature of macular hole development. A macular hole is formed when the anterior cyst wall containing Henle's fiber layer is operculated. Remnants of the photoreceptor cell layer remain on the hole floor in the early stage of macular hole development and subsequently degenerate.

Adult↗

PubMed1995

Infrared angiography of the anterior ocular segment.

We performed angiography with indocyanine green (ICG) and fluorescein using a scanning laser ophthalmoscope (SLO) in the anterior segments of seven normal and 35 diseased eyes. ICG angiography revealed the radical stromal vessels and minor arterial circle in brown irides, which were not detected by fluorescein angiography. High penetration of infrared fluorescence through the pigmented tissue and absence of extravasation of ICG facilitated demonstration of the fine structure of iris rubeosis and its origins from stromal vessels. In 11 diabetic eyes, the iris rubeosis showed three basic patterns of location: along the pupillary margin; originating from the iris root; and arising from stromal radial vessels near the collarette. ICG gonioangiography with SLO showed fine structure of angle rubeosis because of its high resolution and greater depth in focus. Rubeotic vessels in the chamber angle were perfused by neovascular trunks which arose from the iris root in all 12 rubeotic eyes. Rubeosis in the iris and the angle consistently showed no extravasation of the ICG dye, while fluorescein quickly leaked out. ICG angiography with SLO in the anterior ocular segment proved to be a useful means to study the structure and the hemodynamics of normal and newly formed vessels.

Adult↗

PubMed1995

Subsequent epilepsy in very-low-birthweight infants: a long-term follow-up study from birth.

We studied 197 survivors of 290 very-low-birthweight (VLBW, < 1,500 g) infants admitted to our neonatal intensive care unit from 1977 through 1982. The children were all followed until at least age 6 years (mean 10 years 6 months). Eight children (4.1%) had epilepsy: 5 had generalized, 2 had unilateral, and 1 had partial seizures. Two (1.0%) had active and poorly controlled epilepsy. Three had a history of epileptic seizures, but none for > or = 6 years, and 3 were no longer receiving antiepileptic drug (AED) treatment. Most (5 of 8) were severely multiply handicapped. As compared with VLBW children without epileptic seizures and neurodevelopmental abnormalities, VLBW children with epileptic seizures had a gestational age < 27 weeks, a weight < 1,000 g, severe perinatal complications as indicated by an Apgar score of < 4 at 5 min, and the need for long-term oxygen administration.

Apgar Score↗

PubMed1994

Oval defect in detached posterior hyaloid membrane in idiopathic preretinal macular fibrosis.

We examined the vitreous of 71 eyes with idiopathic preretinal macular fibrosis and observed complete posterior vitreous detachment in 48 eyes (68%), partial posterior vitreous detachment in 16 eyes (22%), and no posterior vitreous detachment in seven eyes (10%). Among the 48 eyes with posterior vitreous detachment, we observed that the detached posterior hyaloid membrane had an oval or round defect in 31 eyes (65%) and a break in the premacular area in 12 eyes (25%). The size and the contour of the premacular defects in the posterior hyaloid membrane corresponded to those characteristic of premacular fibrosis. A premacular oval defect in the detached posterior hyaloid membrane indicates that the vitreous cortex is a structural component of idiopathic premacular fibrosis. We postulate that the thin, premacular vitreous cortex, which forms the posterior wall of the premacular liquefied pocket, plays a key role in the development of idiopathic preretinal macular fibrosis in eyes with or without posterior vitreous detachment.

Adolescent↗

PubMed1994

Inhibitory effect of zinc compounds on osteoclast-like cell formation in mouse marrow cultures.

The effect of zinc compounds on osteoclast-like cell formation in mouse marrow culture in vitro was investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone resorbing agent [1,25-dihydroxyvitamin D3, parathyroid hormone (1-34), interleukin-1 alpha or prostaglandin E2]. Osteoclast-like cell formation was estimated by staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of 1,25-dihydroxyvitamin D3 (10(-8) M), parathyroid hormone (10(-8) M), interleukin-1 alpha (50 U/mL) or prostaglandin E2 (10(-6) M) induced a remarkable increase in osteoclast-like multinucleated cells. These increases were inhibited by the presence of zinc sulfate or zinc-chelating dipeptide (beta-alanyl-L-histidinato zinc; AHZ) in the concentration range of 10(-8) to 10(-5) M. The inhibitory effect of AHZ (10(-8) and 10(-7) M) was more intensive than that of zinc sulfate. Furthermore, the presence of Ni2+, Cu2+, Mn2+ or Co2+ (10(-7) and 10(-6) M) did not have an effect on parathyroid hormone (10(-8) M)-induced osteoclast-like cell formation. The present study clearly demonstrates that zinc compounds have a potent inhibitory effect on osteoclast-like cell formation in mouse marrow culture.

Acid Phosphatase↗

PubMed1994

Differential effects of insulin and insulin-like growth factor-I in the femoral tissues of rats with skeletal unloading.

The alteration of bone metabolism in the femur of rats with skeletal unloading for 4 days was investigated. Skeletal unloading was designed using the model of hindlimb hang in rats. Skeletal unloading caused a significant decrease in femoral weight, calcium, and phosphorus contents in the metaphysis but not diaphysis. Also, the unloading induced a significant decrease of zinc content, alkaline phosphatase activity, and deoxyribonucleic acid (DNA) content in the femoral diaphysis and metaphysis. When the femoral-diaphyseal and metaphyseal tissues from normal and skeletal-unloading rats were cultured in the presence of insulin (10(-9) and 10(-8) M) for 24 hours in vitro, the hormonal effect to increase alkaline phosphatase activity and DNA content in the diaphysis, but not metaphysis, was lost in the bone tissues from unloading rats. However, the culture with insulin-like growth factor-I (IGF-I; 10(-8) and 10(-7) M) produced a significant increase of alkaline phosphatase activity and DNA content in both the diaphyseal and metaphyseal tissues from normal and unloading rats. These results demonstrate that skeletal unloading causes an impairment of insulin effect, but not IGF-I effect, on bone metabolism in femoral tissues.

Alkaline Phosphatase↗

PubMed1994

Effect of zinc-chelating dipeptide on bone metabolism in weanling rats: comparison with beta-alanyl-L-histidinato zinc-related compounds.

Rats were orally administered zinc sulfate, di(histidino)-zinc (HZ), beta-alanyl-L-histidinato zinc (AHZ), and di(N-acetyl-L-alanyl-L-histidinato)-zinc (AAHZ) with the doses of 2.75 and 5.50 mg Zn/kg/day for 7 days, and 24 h later they were killed. With the dose of 2.75 mg Zn/kg/day, the administration of AHZ caused a significant increase of zinc content in the femoral diaphysis and a corresponding elevation of alkaline phosphatase activity, deoxyribonucleic acid (DNA), and calcium contents, but similar doses of zinc sulfate, HZ, and AAHZ did not have an appreciable effect on the enzyme activity and DNA content. Moreover, the dose of 5.50 mg Zn/kg/day with AHZ and AAHZ caused an appreciable increase in all zinc compounds observed, whereas zinc sulfate did not have the effect on bone DNA content and HZ had no effect on bone alkaline phosphatase activity. Of the various zinc-chelating dipeptides used, AHZ had a characteristic effect on bone metabolism in weanling rats. Thus, AHZ may have a pharmacological role.

Animals↗

PubMed1994

Effect of zinc-chelating dipeptides on osteoblastic MC3T3-E1 cells: activation of aminoacyl-tRNA synthetase.

The effect of zinc-chelating dipeptides on osteoblastic MC3T3-E1 cells was investigated. As zinc compounds, we used zinc sulfate, AHZ, di(N-acetyl-beta-alanyl-L-histidinato)zinc (AAHZ), and di(histidino)zinc (HZ). Cells were cultured for 72 h in the presence of zinc compounds (10(-8)-10(-5) M). The effect of AHZ (10(-7) and 10(-6) M) to increase protein and deoxyribonucleic acid (DNA) contents in the cells was the greatest in comparison with those of other zinc compounds. Zinc sulfate and HZ at 10(-7) M did not have an effect on the cellular protein content. AHZ (10(-6) M) had a potent effect on cell proliferation, although zinc sulfate (10(-6) M) had no effect. beta-Alanyl-L-histidine (10(-6) and 10(-5) M) did not have an appreciable effect on the cells. Those effects of AHZ (10(-6) M) on osteoblastic cells were completely abolished by the presence of cycloheximide (10(-6) M). AHZ (10(-8)-10(-5) M) directly activated [3H]leucyl-tRNA synthetase in the cell homogenate, whereas the effect of zinc sulfate was seen at 10(-6) and 10(-5) M. The present study suggests that the chemical form of zinc-chelating beta-alanyl-L-histidine (AHZ) can reveal a potent anabolic effect on osteoblastic cells, and that AHZ directly stimulates protein synthesis.

3T3 Cells↗