Bilateral giant macular hole.
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Diagnostic Techniques, Ophthalmological↗
Biomedical subjects
S Kusaka
Publications and source records attributed to S Kusaka.
Retinal changes after retinal translocation surgery with scleral imbrication in dog eyes.
PURPOSE: To examine retinal changes induced by scleral imbrication during retinal translocation surgery in dog eyes. METHODS: Fifteen dogs were anesthetized and underwent retinal translocation surgery. After lensectomy and vitrectomy, an intentional retinal detachment was created, and the upper temporal sclera around the equator was imbricated with five mattress sutures. Translocated distances were calculated by pre- and postoperative photographs. At 1, 2, and 4 weeks after the surgery, the retina was studied by TdT-dNTP terminal nick-end labeling (TUNEL) and immunohistochemistry of peanut agglutinin (PNA) lectin and glial fibrillary acidic protein (GFAP). RESULTS: The retina was translocated by a mean distance of 0.53 +/- 0.30 disc diameters or 959 +/- 543 micrometer. Retinal folds were created around the optic disc in all eyes. Histologic examination of the retinal folds 1 week after the surgery showed many TUNEL-positive cells in the outer nuclear layer, loss of photoreceptor cells, and shortening of the outer and inner segments. A strong immunoreactivity to GFAP was detected in the folds of the retina. CONCLUSIONS: . The results demonstrated that retinal translocation surgery by scleral imbrication inevitably caused retinal folds as a postoperative complication, and the retina within the folds showed extensive loss of photoreceptor cells. It is recommended that the foveal translocation surgery be planned to avoid involving the fovea in the retinal folds.
Animals↗
Expression and polarized distribution of an inwardly rectifying K+ channel, Kir4.1, in rat retinal pigment epithelium.
1. In the eye, different substances and ions including potassium (K+) are transported between neural retina and choroid via the subretinal space. Inwardly rectifying K+ channels (Kir) on the apical membrane of retinal pigment epithelial (RPE) cells are thought to play an essential role in K+ transport in the subretinal space. 2. Single-channel recordings from the apical membrane of RPE cells exhibited functional expression of a Kir channel with properties identical to those of Kir4.1, while recordings from the basolateral membrane showed no detectable Kir channel currents. 3. The expression of Kir4.1 mRNA in RPE cells was confirmed by RT-PCR analysis and in situ hybridization. Furthermore, using immunohistochemistry, we found that Kir4.1 was prominently expressed in RPE cells and localized specifically on the processes on their apical membrane. 4. Developmental studies revealed that expression of Kir4.1 started to appear 10 days or later after birth in RPE cells, in parallel with the maturation of retinal neuronal activity as represented by the a- and b-waves of the electroretinogram. 5. These data suggest that Kir4.1 is one of the Kir channels involved in RPE-mediated control of K+ ions in the subretinal space.
Animals↗
Plasma-induced changes in the physiology of mammalian retinal glial cells: role of glutamate.
Plasma can leak into the nervous system when the vascular endothelial barrier is compromised. Although this occurs commonly, little is known about the effects of plasma on the function of cells in the central nervous system. In this study, we focused on the responses of glial cells, which, because they ensheathe the blood vessels, are the first cells exposed to leaking plasma. We used the perforated-patch configuration of the patch-clamp technique to assess the effects of plasma on freshly dissociated bovine and human Müller cells, the principal glia of the retina. To monitor the function of Müller cells in situ, we recorded electroretinograms from isolated retinas. We found that plasma activates an electrogenic glutamate transporter and inhibits inward-rectifying K+ channels, as well as a transient outward current. Glutamate, a normal constituent of the blood, mimicked these effects. Unlike our recent findings with serum, which contains molecules generated by the clotting process, plasma neither activated a nonspecific cation conductance nor inhibited the slow P(III) component of the electroretinogram, which is generated by Müller cells responding to light-evoked changes in the extracellular potassium concentration ([K+]o). Taken together, our observations indicate that a leakage of serum into the retina compromises the regulation of [K+]o by Müller cells; however, when plasma enters the retina at sites of a breakdown in the blood-retinal barrier, these glia can maintain K+ homeostasis while reducing the potentially neurotoxic levels of glutamate.
Animals↗
Analysis of vitrectomy for idiopathic macular hole by optical coherence tomography.
PURPOSE: To evaluate foveal structure after vitrectomy for idiopathic macular hole in relation to postoperative visual outcome. METHODS: Optical coherence tomography was performed postoperatively to assess retinal thickness at the foveal center in patients who underwent vitrectomy, posterior hyaloid membrane removal, and perfluoropropane gas tamponade for idiopathic macular hole. Thirty-seven eyes of 36 patients documented to have achieved anatomic hole closure by optical coherence tomography were included in the study. RESULTS: Increased visual acuity significantly correlated with greater foveal thickness assessed at a median of 5 months postoperatively (Spearman analysis; R = .453, P = .005). CONCLUSION: Visual outcome after anatomic closure of macular holes by vitrectomy is closely related to the structure of the center of the fovea postoperatively.
Aged↗
Synthetic studies of an 18-membered antitumor macrolide, tedanolide. 5. Stereoselective synthesis of the C13-C23 part via condensation of two fragments, C13-C17 and C18-C21, by taking advantage of the 3,4-dimethoxybenzyl protecting group.
An efficient and stereoselective synthesis of the C13-C23 part (8) was achieved starting from methyl (R)- and (S)-3-hydroxy-2-methylpropionates (9) via coupling of the C13-C17 aldehyde (6), prepared by Evans asymmetric aldol reaction, with the C18-C21 iodoalkene (5b) by taking advantage of the 3,4-dimethoxybenzyl protecting group.
Anti-Bacterial Agents↗
[Aspergillosis following influenza A infection].
An 83-year-old man had an influenza-like upper respiratory infection that progressed to pneumonia and respiratory insufficiency during a period two weeks. After admission, anti-influenza A antibody increased 32-fold and antibiotic treatment had little effect on the pneumonia. Aspergillus antigen was detected from his serum and pleural effusion, however, culture of sputum was negative for aspergillus. Administration of amphotericin B reduced the serum level of aspergillus antigen, however he died due to the progression of respiratory insufficiency and bloody sputum. Aspergillus infection is generally thought to occur in immunocompromised hosts, but this patient had no apparent immunosuppressive conditions except for his age before the influenza A infection. His WBC and lymphocyte count temporally decreased to 2,000 x 10(6)/L (lymphocytes 160 x 10(6)/L) followed by aspergillus infection. This temporally reduction of lymphocytes is thought to have been responsible for the aspergillus infection. Complications of influenza infection are sometimes fatal and vaccination against influenza seems necessary in high risk individuals such as elderly people.
Aged↗
Serum-induced changes in the physiology of mammalian retinal glial cells: role of lysophosphatidic acid.
1. With a breakdown of the vascular-CNS barrier, serum enters the nervous system. Although this is a frequent pathophysiological event, knowledge of the effects of serum on the function of the nervous system is limited. In this study, we examined the effects of serum on the activity of ion channels in Müller cells: the principal glia of the retina. 2. Freshly dissociated Müller cells from the bovine and human retina were studied with the perforated-patch configuration of the patch clamp technique. In other experiments, electroretinograms (ERGs) were recorded from isolated rat retinas. 3. Perforated-patch recordings revealed that serum induced a calcium-permeable, non-specific cation (NSC) current. Approximately 40 s after induction of this current, an outwardly rectifying K+ current was also detected. Sensitivity to charybdotoxin and margatoxin indicated that this K+ current was due to the activation of Kv1.3 channels. This increase in the Kv1.3 current was dependent on extracellular calcium. 4. The NSC and Kv1.3 currents were activated by serum in 100% and 95% of the sampled Müller cells, respectively. Also, in a minority (21%) of the cells, the inwardly rectifying K+ current was inhibited slightly. These changes in ion channel activity were associated with depolarization of the Müller cells. 5. We hypothesized that activation of NSC channels would reduce the siphoning of K+ via the Müller cells. Consistent with this idea, ERGs from isolated retinas showed serum-induced reductions in the slow PIII component, which is generated by Müller cells responding to light-evoked changes in the extracellular K+ concentration. 6. Lysophosphatidic acid (LPA), a component of serum, had effects on Müller cells that were qualitatively similar to those induced by serum. 7. Our observations demonstrate that exposure to serum alters the activity of multiple types of ion channels in Müller glial cells of the mammalian retina. When there is a breakdown of the blood-retina barrier, LPA may be one of the serum-derived molecules which regulates the physiology of Müller cells.
Animals↗
Anatomic and functional recovery of the fovea after foveal translocation surgery without large retinotomy and simultaneous excision of a neovascular membrane.
PURPOSE: To document the anatomic and functional recovery of the fovea after foveal translocation surgery with scleral shortening and simultaneous excision of a neovascular membrane in a patient with age-related macular degeneration. METHOD: Case report. RESULTS: The visual acuity of a 54-year-old woman with age-related macular degeneration improved from 20/200 to 20/50 after excision of subretinal neovascular membrane and foveal translocation surgery in the right eye. Fixation shifted inferonasally 0.6 disk diameters, corresponding to the direction of foveal translocation, as shown by scanning laser ophthalmoscope microperimetry. Postoperative optical coherence tomography through fixation disclosed normal foveal concavity and intact retinal pigment epithelium. CONCLUSION: Anatomic and functional recovery of the fovea was confirmed in a patient with age-related macular degeneration after foveal translocation surgery with scleral shortening and simultaneous excision of a neovascular membrane.
Female↗
Tangential vitreous traction observed in optic disc pit maculopathy without apparent serous detachment.
The authors describe a rare case of a patient with an optic pit that was accompanied by a cyst-like change in the macula without serous retinal detachment. A 38-year-old woman with a 10-year history of visual impairment in her right eye was referred to the authors' clinic. The best-corrected visual acuity was 20/200 in the right eye, and ophthalmoscopy showed a cyst-like change in the macula with tangential traction by the surrounding vitreous. The patient was treated with vitrectomy and the posterior vitreous was separated from the retina during the procedure. After the surgery, the cyst-like region disappeared and the corrected visual acuity improved to 20/40. The authors suggest that tangential vitreous traction played an important role in the pathogenesis of the optic pit maculopathy.
Adult↗
Intracellular ATP activates inwardly rectifying K+ channels in human and monkey retinal Müller (glial) cells.
1. In the vertebrate retina, the inwardly rectifying K+ (KIR) channels of the Müller (glial) cells are pathways for the redistribution of excess extracellular K+. Due to this role in K+ homeostasis, the activity of Müller cell KIR channels is likely to have significant functional consequences for the retina. In this study we asked whether intracellular ATP regulates the function of KIR channels expressed by Müller cells, the principal glia of the retina. 2. Freshly dissociated Müller cells from the human and monkey (Macaca fascicularis) retina were studied with various configurations of the patch-clamp technique. 3. Whole-cell recordings from Müller cells revealed that a run-down of the inwardly rectifying K+ current (IK(IR)) was prevented if the pipette solution contained Mg-ATP. Chemical ischaemia induced by inhibitors of glycolysis and oxidative phosphorylation caused a nearly 10-fold reduction in the IK(IR)) that was fully restored when metabolically inhibited Müller cells were internally perfused with ATP. 4. In recordings from membrane patches of fresh primate Müller cells, we found that inward-rectifying channels with a conductance of 20 pS in 100 mM Ko+ were the predominant type of KIR channel. In excised patches these 20 pS KIR channels were activated when Mg-ATP was at the cytoplasmic surface. Experiments with inside-out patches indicated that the activity of the 20 pS KIR channels can be maintained by ATP synthesized at sites located close to the channel. 5. The inability of the non-hydrolysable ATP analogue 5'-adenylylimidodiphosphate (AMP-PNP) to prevent the run-down of IK(IR))and the Mg2+ dependence of the ATP effect on KIR channels are consistent with a mechanism of activation requiring the hydrolysis of ATP. 6. These observations suggest that the metabolic state of a Müller cell regulates the activity of its 20 pS KIR channels and thus influences the function of the glial cell in maintaining K+ homeostasis in the retina.
Adenosine Triphosphate↗
Molecular mass of poly[(R)-3-hydroxybutyric acid] produced in a recombinant Escherichia coli.
Poly[(R)-3-hydroxybutyric acid] (PHB) was produced at 37 degrees C by a recombinant Escherichia coli harboring the Alcaligenes eutrophus biosynthesis phb-CAB genes in Luria-Bertani media containing glucose at 10-30 g/l at different pH values and the time-dependent changes in the molecular mass of PHB were studied. PHB polymers accumulated within cells while glucose was present in the medium. The number-average molecular mass of PHB decreased with time during the course of PHB accumulation, and the values for PHB were markedly dependent on the cultivation conditions of the E. coli, ranging from 0.5 MDa to 20 MDa. Under specific conditions (pH 6.0), E. coli produced PHB with an extremely high molecular mass (20 MDa). It has been suggested that a chain-transfer agent is generated in E. coli cells during the accumulation of PHB.
Acyltransferases↗
Response of the extramedullary lung plasmacytoma with pleural effusion to chemotherapy.
An elderly patient with extramedullary lung plasmacytoma and subsequent pleural effusion is described. The presence of abnormal plasma cells in the pleural fluid led to diagnosis. Histologically similar conditions such as multiple myeloma and solitary myeloma of bone were ruled out by clinical evaluation. These neoplasms usually occur in the head and neck area and are not characterized by paraprotein accumulation. Few cases in the lung have been reported. We describe a case of extramedullary plasmacytoma of the lung with plasmacytoma-induced pleural effusion and the presence of monoclonal paraprotein in both the serum and urine. Chemotherapy with melphalan was effective in reducing the size of the plasmacytoma, and pleurodesis was used to manage the pleural effusion.
Aged↗
Spontaneous disappearance of traumatic macular holes in young patients.
PURPOSE: To report the disappearance of traumatic macular hole in three eyes of three patients. METHODS: Clinical data of the patients were reviewed. RESULTS: The three patients were relatively young, ranging in age from 12 to 18 years old. In one eye of each patient, a small traumatic macular hole was observed at the first visit. Visual acuities ranged from 20/100 to 20/40. The macular holes resolved spontaneously 3 to 4 months after the trauma, and final visual acuity improved to 20/20 in all patients. CONCLUSION: Small traumatic macular holes in young patients can resolve spontaneously, and this can be associated with good visual recovery.
Accidents, Traffic↗
Reopening of macular holes in highly myopic eyes with retinal detachments.
BACKGROUND: Gas tamponade with or without vitrectomy is commonly used to treat retinal detachment resulting from a macular hole in a highly myopic eye. Redetachment of the retina occurs frequently, however, and the pathogenesis of redetachment is unclear. One possible mechanism leading to redetachment is tangential traction caused by an epiretinal membrane of the posterior retina. METHODS: Eleven consecutive highly myopic eyes with retinal detachment resulting from a macular hole were treated by vitrectomy, gas or silicone oil tamponade, and removal of an epiretinal membrane. Surgical outcomes and clinical characteristics of these patients were reviewed. RESULTS: An epiretinal membrane was found to be present in all eyes. Of 11 eyes, removal of an epiretinal membrane was complete in six eyes, and macular holes remained closed in all 6 eyes. In five of the 11 eyes, removal of the epiretinal membrane was incomplete. In four of these five eyes, the macular hole reopened. CONCLUSION: Reopening of the macular holes most likely were caused by tangential traction of the remaining epiretinal membranes. It seems that it is important to remove epiretinal membranes as completely as possible during vitrectomy for retinal detachment resulting from a macular hole in a highly myopic eye.
Aged↗
[Treatment of full-thickness macular holes with autologous serum].
A total of 29 eyes in 28 patients with stage 2 to 4 idiopathic full-thickness macular hole were treated with autologous serum. Autologous serum (20-30 microliters) was placed over the macular hole followed by injection of 16% perfluoropropane gas. Postoperatively, twenty-eight eyes (97%) had flattening of the macular hole, and the hole was invisible in 27 eyes (93%). Twenty-two eyes (76%) showed visual improvement of at least two lines or more. Preoperative factors such as good visual acuity, earlier stage, and younger age were correlated with postoperative good visual acuity. These results suggest the benefit of autologous serum in the treatment of full-thickness macular holes.
Adult↗
[Long-term visual recovery after scleral buckling of macula-off retinal detachments].
We retrospectively investigated long-term visual recovery in 32 macular reattached eyes which had been followed up for more than five years after surgery. In 17 eyes (53%), the best-corrected visual acuity at 5 years after surgery was > or = 2 lines better than best-corrected visual acuity at 3 months postoperatively. For these 17 eyes, the mean visual acuity continued to improve for up to 10 years after surgery. In the other 15 eyes, visual acuity changes were within 1 line. Improvement of long-term postoperative visual acuity was found to be statistically correlated with younger age, no or mild myopia (< -5D) and shorter duration of macular detachment (< or = 30 days). Surgeons should be aware that the visual function of reattached retinas may recover in the long-term, especially in eyes with these features.
Adolescent↗
cGMP-mediated effects on the physiology of bovine and human retinal Müller (glial) cells.
1. Whole-cell currents of freshly dissociated or cultured Müller cells from human and bovine retinas were studied using the perforated-patch and standard whole-cell recording techniques. 2. We found that internal perfusion of cGMP or external exposure to 8-bromo-cGMP activated a calcium permeable, non-selective cation current in Müller cells, the principal glial cells of the retina. In addition, the activity of calcium-activated potassium channels increased markedly. These currents were minimally affected by cAMP. 3. Molecular studies using the reverse transcription-polymerase chain reaction demonstrated that human müller cells in culture contain transcripts closely related to the rod cyclic nucleotide-gated (CNG) channel. 4. Since guanylate cyclase is a known target for nitric oxide (NO), we tested the effect of NO donors on Müller cell currents. These agents induced currents that were qualitatively similar to those activated by cGMP. 5. Our experiments support the idea that the NO-cGMP pathway regulates the physiology of Müller cells and may play a role in integrating neuron-glia interactions in the retina.
8-Bromo Cyclic Adenosine Monophosphate↗