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Biomedical subjects

Yoshiko Sagara

Publications and source records attributed to Yoshiko Sagara.

13 recordsLinked to original sources
PubMed2006

Hypothermia of 8 degrees C protects cultured retinal pigment epithelial cells and retinal ganglion cells against trypan blue toxicity.

PURPOSE: To determine whether hypothermia of 8 degrees C can protect cultured human retinal pigment epithelial (ARPE-19) cells and rat retinal ganglion cells (RGC-5) against trypan blue (TB) toxicity. DESIGN: Laboratory investigation. METHODS: ARPE-19 cells and RGC-5 were exposed to balanced salt solution as controls, and 0.05% and 0.5% TB at 37 degrees C, and at 8 degrees C for one minute. The percentage of surviving cells was determined by the resazurin test. RESULTS: TB induced a statistically significant decrease in the percentage of ARPE-19 cells surviving at 0.5% TB at 37 degrees C (P < .01). Conversely, TB induced a statistically significant decrease in the percentage of RGC-5 surviving at all conditions except for 0.05% TB at 8 degrees C (0.05% 37 degrees C; P < .05, 0.5% 37 degrees C and 8 degrees C; P < .01). CONCLUSIONS: These results indicate that reducing the temperature to 8 degrees C has a protective effect against the TB toxicity for ARPE-19 cells and RGC-5 in culture.

Animals↗
PubMed2006

Hypothermia protects cultured human retinal pigment epithelial cells against trypan blue toxicity.

PURPOSE: To determine whether trypan blue (TB) is toxic to cultured human retinal pigment epithelial (ARPE-19) cells, and whether hypothermia can protect ARPE-19 cells against TB toxicity. METHODS: ARPE-19 cells were cultured and exposed to balanced salt solution as a control, while other cells were exposed to 0.05, 0.2, and 0.5% TB dye at 37 and 4 degrees C for 5 and 30 min. The percentage of ARPE-19 cells that survived was determined by resazurin 1 day after the exposure. RESULTS: A statistically significant decrease in the percentage of ARPE-19 cells surviving was found after exposure to 0.2 and 0.5% TB at any temperature or for any exposure duration (p < 0.01). The percentage of RPE cells surviving at 0.05% was not significantly different from that of controls except for a 30-min exposure at 37 degrees C. The percentage of cells surviving at 4 degrees C for a 5-min exposure to 0.5% TB and a 30-min exposure to 0.2 and 0.5% was significantly higher than that at 37 degrees C under each condition (p < 0.01 for all). CONCLUSIONS: These results indicate that TB is toxic to human RPE cells, and the toxicity is dose- and exposure duration-dependent. Exposing the cells at 4 degrees C had a protective effect against higher concentrations or longer exposure durations of TB compared to exposure at 37 degrees C.

Cell Count↗
PubMed2006

Recombinant AAV-transduced iris pigment epithelial cell transplantation may transfer vector to native RPE but suppress systemic dissemination.

PURPOSE: To determine whether adenoassociated virus (AAV) vectors transduced into iris pigment epithelial (IPE) cells and transplanted into the subretinal space of rats will transfer the AAV genome to the host cells and whether the vectors are disseminated systemically. METHODS: Recombinant (r)AAV was transduced into rat IPE cells and transplanted into the subretinal space of rats. For the control, rAAVs alone were injected subretinally. The transplanted IPE cells were detected by LacZ staining. Immunohistochemistry, electron microscopy, electroretinography, and fluorescein-dextran angiography were performed. DNA was extracted from various organs and blood and examined for the AAV genome by polymerase chain reaction. RESULTS: No toxicity from rAAV transduction was observed in vitro. LacZ was expressed in the transplanted cells 1 and 2 weeks after transplantation. At 4 and 12 weeks, fewer transplanted cells were detected than at 1 week, and LacZ expression was occasionally detected at the level of host retinal pigment epithelial (RPE) cells. Expression was also detected in ciliary body epithelial cells. The electroretinograms and fluorescein-dextran angiography were only mildly altered. Significantly lower levels of AAV genome were detected in the organs and blood of rats receiving rAAV-IPE cell transplants than with direct intravenous injection of AAV vectors. CONCLUSIONS: AAV-mediated LacZ was expressed in the transplanted cells after subretinal transplantation, and the transplanted IPE cells may transfer the rAAV to host tissues, such as RPE cells, long after the transplantation. This method of gene delivery did not lead to systemic dissemination of the vectors.

Animals↗
PubMed2006

Visual function with acupuncture tested by visual evoked potential.

Visual evoked potential (VEP) testing is used frequently and is an important ophthalmologic physiological test to examine visual functions objectively. The VEP is a complicated waveform consisting of negative waveform named N75 and N135, and positive waveform named P100. Delayed P100 latency and greatly attenuated amplitude on VEP are known characteristics for diagnosing optic nerve disease. Acupuncture has been used to treat wide clinical symptoms with minimal side effects. The confirmation of the efficacy of acupuncture generally relies on subjective symptoms. There is not much scientific evidence supporting the acupuncture treatments for eye diseases up to today. However, the VEP test can evaluate objectively and numerically the efficacy of the treatment by the acupuncture. We analyzed 19 healthy subjects (38 eyes). The P100 latencies in the group of less than 101.7 msec (total average) before acupuncture stimulations were not different than those after treatment (98.2 +/- 3.0 msec, 98.2 +/- 4.0 msec, respectively, p = 0.88, n = 17), but the latencies in those subjects with longer or equal to 101.7 msec were statistically different after acupuncture (104.6 +/- 2.8 msec, 101.9 +/- 3.7 msec, respectively, p = 0.006, n = 21). These results show that the acupuncture stimulation contributes to the P100 latencies of pattern reversal (PR)-VEP to some subjects who have delayed latencies, and this electrophysiological method is a valuable technique in monitoring the effectiveness of acupuncture therapy in the improvements of visual functions. The purpose of this study is to evaluate the physiological effects by acupuncture stimulations using PR-VEP in normal subjects.

Acupuncture Therapy↗
PubMed2005

Targeted disruption of FSCN2 gene induces retinopathy in mice.

PURPOSE: To investigate the morphology and function of photoreceptors in mice with mutation of the FSCN2 gene. METHODS: A mouse line was generated carrying the 208delG mutation (point mutation, or p-type) and another with replacement of exon 1 by the cDNA of a green fluorescent protein (GFP knock-in, or g-type). The expression of retinal mRNA was determined by reverse transcription (RT)-polymerase chain reaction (PCR) and in situ hybridization performed on retinal sections. Morphologic analyses of the retinas were performed by light microscopy (LM) and transmission electron microscopy (TEM) and functional analyses by electroretinogram (ERG). RESULTS: mRNA of FSCN2 was not detected in the retinal mRNA extracted from FSCN2p/p and FSCN2g/g mice. Both FSCN2(+/p) and FSCN2(+/g) mice had progressive photoreceptor degeneration with increasing age detected by LM and structural abnormalities of the outer segment (OS) detected by TEM. Both FSCN2(+/p) and FSCN2(+/g) mice had depressed rod and cone ERGs that worsened with increasing age. CONCLUSIONS: These results indicate that haploinsufficiency of the FSCN2 gene may hamper maintenance and/or elongation of the OS disks and result in photoreceptor degeneration, as in human autosomal dominant retinitis pigmentosa.

Animals↗
PubMed2005

Limitations of three-dimensional reconstructed computerized tomography angiography after clip placement for intracranial aneurysms.

OBJECT: The authors compared the usefulness of three-dimensional (3D) reconstructed computerized tomography (CT) angiography with 3D digital subtraction (DS) angiography in assessing intracranial aneurysms after clip placement. A retrospective review of clinical cases was performed. METHODS: Between May 2001 and May 2003, 17 patients with a total of 20 intracranial aneurysms underwent 3D CT and 3D DS angiography following clip placement. The authors assessed the presence or absence of residual aneurysm necks and stenoocclusive changes in the parent artery and the neighboring artery. The efficacy of CT angiographic visualization was also evaluated. In 12 of the 20 aneurysms, both 3D modalities similarly demonstrated the residual aneurysm neck and stenoocclusive changes in the parent artery and neighboring artery. Three-dimensional CT angiography failed to demonstrate three of the aneurysms, and the studies were not considered suitable for evaluation because of the presence of metallic artifacts. In the remaining five studies, the 3D CT angiograms did not effectively demonstrate the neighboring and parent arteries. The detectability of residual aneurysm necks was correlated with the clip material and with the number of clips applied. CONCLUSIONS: Three-dimensional DS angiography is still necessary in cases involving multiple clips or with cobalt alloy clips because the clips appear as metal artifacts on 3D CT angiography.

Adult↗
PubMed2004

Turn-back technique with use of a shaped microcatheter for superselective catheterization of arteries originating at acute angles.

The authors have developed a novel "turn-back" technique with use of a shaped microcatheter for superselective catheterization of arteries originating at acute angles. Herein this technique is described in clinical use for superselective catheterization of several arteries including the middle hepatic artery, right gastric artery, right inferior phrenic artery, and tracheal artery in six patients after failed catheterization by conventional techniques as a result of difficult geometry of the arteries. Superselective catheterization and intervention were successfully performed without complication in all cases. This turn-back technique is useful for superselective catheterization of arteries originating at acute angles.

Aged↗
PubMed2002

Diagnostic accuracy of magnetic resonance angiography for cerebral aneurysms in correlation with 3D-digital subtraction angiographic images: a study of 133 aneurysms.

BACKGROUND AND PURPOSE: We investigated the sensitivity of 3D-time-of flight (3D-TOF) magnetic resonance angiography (MRA) in the detection of cerebral aneurysms with the use of 3D digital subtraction angiography as the gold standard. We also evaluated the effects of location and number of aneurysms (and experience of the reader) on the sensitivity. METHODS: 3D-TOF MRA was performed in 82 patients with 133 cerebral aneurysms. Each patient underwent rotational angiography. Three-dimensional reconstructed images were obtained from data of the rotational angiography (as the gold standard). A blind study with 4 readers of different experiences was performed to evaluate the diagnostic accuracy of 3D-TOF MRA for cerebral aneurysms. RESULTS: One hundred five (79%) of all 133 aneurysms were detected with MRA by a neuroradiologist, 100 (75%) were detected by an experienced neurosurgeon, 84 (63%) were detected by a general radiologist, and 80 (60%) were detected by a resident neuroradiologist. For each reader, the detectability was lower for small aneurysms (<3 mm in maximum diameter) and/or for those located at the internal carotid artery and anterior cerebral artery. False-positive aneurysms were 29 for the neuroradiologist, 19 for the neurosurgeon, 31 for the general radiologist, and 30 for the resident neuroradiologist; most of the aneurysms were at the internal carotid artery. Causes of the false-positive and false-negative results included complex flow in a tortuous artery and susceptibility artifacts. CONCLUSIONS: Although MRA is useful in the diagnosis of cerebral aneurysms, sufficient experience and careful attention are necessary for accurate diagnosis of aneurysms located at the internal carotid and anterior cerebral arteries.

Adult↗
PubMedDate not supplied

Treatment of intracranial dural arteriovenous fistulas: current strategies based on location and hemodynamics, and alternative techniques of transcatheter embolization.

Intracranial dural arteriovenous fistulas (AVFs) can occur anywhere within the dura mater. Patients may be clinically asymptomatic or may experience symptoms ranging from mild symptoms to fatal hemorrhage, depending on the location (eg, cavernous sinus, transverse-sigmoid sinus, tentorium, superior sagittal sinus, anterior fossa) and venous drainage pattern of the AVF. In the past, dural AVFs have been treated with a variety of approaches, including surgical resection, venous clipping, transcatheter embolization, radiation therapy, or a combination of these treatments. Recent developments in catheter intervention now allow most patients to be cured with transcatheter embolization, although stereotactic radiation therapy is demonstrating good results in an increasing number of cases and surgery is still the preferred option in some cases. Familiarity with drainage patterns, the risk of aggressive symptoms, recent technical advances, and current treatment strategies is essential for the treatment of intracranial dural AVFs.

Catheterization↗
PubMedDate not supplied

Dispersion of coils after parent-artery occlusion of radiation-induced internal carotid artery pseudoaneurysm.

We report a rare complication following parent-artery occlusion in a patient with radiation-induced carotid pseudoaneurysms. Both the right internal carotid artery pseudoaneurysm and the recurrent external carotid artery pseudoaneurysm were treated by parent-artery occlusion with coils. Although rebleeding was not observed after the second embolization, angiography and endoscopy at the 12-month follow-up showed dispersion and migration of coils into the pharynx and the external auditory canal due to progressive radiation necrosis.

Carotid-Cavernous Sinus Fistula↗
PubMedDate not supplied

Clinical use of a new mechanical detachable coil system for percutaneous intravenous embolization of cavernous sinus dural arteriovenous fistulas.

PURPOSE: The purpose of this study was to evaluate the usefulness of a new mechanical detachable coil system (Detach-18/-11) for percutaneous transvenous embolization (TVE) of dural arteriovenous fistulas (AVFs) involving the cavernous sinus. MATERIALS AND METHODS: Five patients with dural AVF involving the cavernous sinus were treated by TVE with the use of the Detach-18/-11 system alone. All procedures were analyzed with regard to the processes of introduction, delivery, and/or retrieval of the Detach-18/-11 system, and angiographical and clinical outcome. RESULTS: A total of 70 detachable coils (37 spiral-type coils and 33 J-type coils) were used. Two coils were easily retrieved after introduction. The remaining 68 coils were easily delivered within 30 seconds. Neither premature detachment nor coil migration was observed. Of the five dural AVFs, three were completely occluded and two were nearly completely occluded immediately after embolization. Follow-up angiography showed complete occlusion in all cases. Clinical symptoms had disappeared within one month, and no recurrent symptoms were observed during follow-up (from 5 to 36 months). CONCLUSION: Our results support the safety and reliability of the Detach-18/-11 system for TVE of dural AVF. The availability of various types of this coil system allows sufficient packing of the involved sinus.

Aged↗
PubMedDate not supplied

Shapability, memory, and luminal changes in microcatheters after steam shaping: a comparison of 11 different microcatheters.

PURPOSE: The purpose of this study was to compare the characteristics of shaped microcatheters, including shapability, durability, and luminal changes. MATERIALS AND METHODS: Eleven brands of steam-shaped microcatheters and one brand of preshaped microcatheter were evaluated. There were 2 nonreinforced and 10 reinforced devices supported by coils. For evaluation of shapability, the tip angle of 6 samples of each brand were measured after steam-shaping for 20 seconds with a shaping mandrel bent at a 90 degrees or 150 degrees angle. The ability to maintain the shaped angle after guidewire insertion stress (durability) was compared by calculation of the change in the tip angle by using 3 samples of each brand. Luminal change after steam shaping was evaluated by calculation of narrowing rate of the smallest diameter and observation of the surface morphology of the mold of each catheter lumen by using a silicone polymer by means of a fluorescent projection method. RESULTS: The nonreinforced microcatheters and the fiber-braided microcatheter showed higher shapability than the others. The degree of distal microcatheter straightening with the microguidewire insertion was less pronounced in the preshaped microcatheter and the fiber-braided microcatheter. Spontaneous recovery to the initial tip angle 5 minutes after the guidewire procedure was observed in 10 brands to various degrees (87%-98%). Irregular luminal surface morphology at the angled portion was found in 6 reinforced brands. One nonreinforced catheter and the fiber-braided catheter showed high narrowing rates >6%. CONCLUSION: There are differences in shapabilty, durability, and luminal changes of steam shaping in 12 brands of microcatheters. These characteristics could be important factors in catheter choice for endovascular procedures.

Catheterization↗