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Biomedical subjects

A Sawada

Publications and source records attributed to A Sawada.

At least 91 records · Page 5Linked to original sources
PubMed1996

Surgery for refractory glaucoma.

PURPOSE: To determine the surgical outcome of mitomycin trabeculectomy in patients with refractory glaucoma. METHODS: Sixty-six eyes of 52 patients with refractory glaucoma underwent mitomycin trabeculectomy. Mitomycin was applied for five minutes only once during trabeculectomy. The follow-up period was six to 61 months. RESULTS: Cumulative success probability was calculated using Kaplan-Meier life-table analysis assuming the cut-off postoperative IOP to be 20 mmHg or IOP reduction by at least 20% in eyes with preoperative IOP 24 mmHg. At the end of 61-month follow-up the success probability was 80% +/- 6% without postoperative ocular hypotensive medication (complete success) and was 95% +/- 3% regardless of postoperative antiglaucoma medication (overall success), respectively. CONCLUSION: The data suggest that mitomycin trabeculectomy is efficacious in reducing IOP in patients with refractory glaucoma.

Adolescent↗
PubMed1996

Retinitis pigmentosa with recurrent vitreous hemorrhage.

We observed recurrent vitreous hemorrhage in two patients with retinitis pigmentosa: a 41-year-old female and a 49-year-old male. At age 41, the first patient had diffuse capillary dilatation, macular microaneurysms, and paramacular macroaneurysms in the right eye. At age 47, similar retinal vascular lesions and disc neovascularization developed in the left eye followed by recurrent vitreous hemorrhage. The retinal microvascular changes and vitreous hemorrhages subsided spontaneously during the ensuring 4 years. In the second case, recurrent vitreous hemorrhage developed in the right eye. Funduscopy and fluorescein angiography at age 49 revealed no angiopathy. However, 2 years later we detected retinal neovascularization in the macula and an avascularity in the peripheral retina in the right eye. Subretinal exudate or retinal detachment was consistently absent in both cases.

Adult↗
PubMed1996

Electrical responses from locally detached retina and its recovery after reattachment.

Alterations in the focal electroretinogram (FERG) after experimental retinal detachment and spontaneous reattachment in albino rabbits were studied. Retinal detachments of two disc diameters were produced by injecting balanced salt solution into the subretinal space. FERGs were obtained under direct fundus visualization by an infrared television fundus camera with a light stimulator. The preoperative b-wave amplitude and implicit time were 0.52 +/- 0.07 microV and 59.7 +/- 3.8 ms (mean +/- SD), respectively. Thirty minutes after retinal detachment, the amplitude decreased significantly to 0.05 +/- 0.09 microV (p < 0.0001). The next day, we confirmed retinal reattachment ophthalmoscopically and the amplitude recovered to 0.30 +/- 0.07 microV. Then it gradually increased to 0.54 +/- 0.07 microV 7 days after the operation. The implicit time increased significantly to 66.6 +/- 4.1 ms 30 min after retinal detachment (p < 0.01), was maximal the day after surgery (69.9 +/- 4.9 ms), and thereafter shortened. However, the implicit time did not recover completely and was significantly delayed compared with preoperatively even 28 days postoperatively (65.4 +/- 3.4 ms, p < 0.01). These data suggest that functional abnormalities persist in the reattached rabbit retina, even following a brief retinal detachment.

Animals↗
PubMed1996

Nitric oxide-sensitive and -insensitive contractions of the isolated rabbit iris sphincter muscle.

PURPOSE: The rabbit iris sphincter muscle is innervated by cholinergic and tachykinergic nerves that regulate its tone. To clarify the involvement of nitric oxide (NO) in the postsynaptic regulation of the rabbit iris sphincter muscle tone, the authors examined the effects of NO-related agents on the cholinergic contraction induced by carbamylcholine (carbachol) and the tachykinergic contraction induced by neurokinin A. METHODS: The motor activity of the ring-shaped rabbit iris sphincter muscle was measured isometrically. Sodium nitroprusside (SNP, a NO donor) was administered between the first and second administrations of carbachol and neurokinin A, each of which induced sustained contraction. The effects of carboxy-2-phenyl-4,4,5,5,-tetramethyl-imidazoline-l-oxyl-3-oxide (carboxy-PTIO, a scavenger of NO radicals), NG-monomethyl-L-arginine (L-NAME, an inhibitor of NO formation from L-arginine), and methylene blue (an inhibitor of soluble guanylate cyclase) on contractions induced by carbachol and neurokinin A also were studied. Cyclic guanosine monophosphate (GMP) content in the muscle was determined by radioimmunoassay. RESULTS: Sodium nitroprusside inhibited carbachol-induced contractions of the iris sphincter muscle in a concentration-dependent manner but had no effect on neurokinin A-induced muscle contractions. Carboxy-PTIO and methylene blue significantly diminished the inhibitory effect of SNP on carbachol-induced contractions. L-NAME had no effect on contractions induced by either carbachol or neurokinin A. Sodium nitroprusside alone increased cyclic GMP accumulation in a concentration-dependent manner. CONCLUSIONS: This study showed that SNP inhibited cholinergic contractions mainly through a cyclic GMP-dependent mechanism but did not affect the tachykinergic contractions, indicating that cholinergic contraction is NO sensitive, whereas tachykinergic contraction is NO insensitive. These findings suggest that in rabbits, the cholinergic and tachykinergic responses have distinct features for the fine adjustment of the iris sphincter muscle tone.

Animals↗
PubMed1996

[Multi-focal electroretinograms in normal subjects].

The multi-focal electroretinogram (multi-focal ERG), developed by Sutter (1992), is a method of recording the spatial distribution of focal ERG in a short time using multi-input stimulation. Using this technique, we can detect the spatial extent and severity of damage to the macula. In this study, we recorded multi-focal ERGs from 20 eyes of 20 normal subjects and analyzed the topographical property of responses. In every subject, a negative wave followed by a positive wave could be recorded and we named them the N1-wave and the P1-wave, respectively. The amplitudes of the N1-wave and the P1-wave were the largest in the fovea and they became smaller with eccentricity. In P1-wave amplitude, the greatest inter-subject variability was observed at the fovea. The N1 and P1 latencies were shorter in the upper retina than in the lower retina. The amplitude was larger in the upper retina than in the lower retina, which suggests functional superiority of the upper retina. There was no statistical difference of latency and amplitude between nasal and temporal retina. We found no statistical difference between the responses of the papillomacular bundle and those of the temporal retinal area. The mapping obtained by multi-focal ERG was useful as objective perimetry.

Adult↗
PubMed1996

[A case of morning glory syndrome associated with contractile movement of the optic disc and subretinal neovascularization].

We report a rare case of morning glory syndrome with choroidal neovascular membrane and contractile movement of the optic disc. A 12-year-old healthy boy was first seen in April 1992 with a chief complaint of transient visual loss in his left eye for 3 months. The diagnosis of morning glory syndrome was made by the characteristic optic nerve head. His visual acuity was 1.2 in both eyes. In August 1994, retinal hemorrhage associated with choroidal neovascular membrane was observed in the macula of his left eye, resulting in a decrease of visual acuity to 0.4. In October 1994, we observed contractile movement in the morning glory optic disc. Using a scanning laser ophthalmoscope (SLO), we could observe the disc contracting for approximately 2 seconds and then dilating again over a 20-second period. The contractile movement was not evoked by exposure to a strong light or by the Valsalva maneuver. However, it seemed to be induced by digital massage of the eyeball.

Child↗
PubMed1996

Effect of vitrectomy on epiretinal membranes after endogenous fungal endophthalmitis.

Pars plana vitrectomy was used to remove proliferative membranes caused by endogenous fungal endophthalmitis in 3 patients (3 eyes). Tractional retinal detachment was present in all. In 2 eyes, a fibrovascular membrane originated in the optic nerve head and was connected to a full-thickness chorioretinal scar. In the other, a thick preretinal membrane was found in the macula, with total retinal detachment. In all eyes, the epiretinal membrane was successfully removed and the retina reattached. Visual outcome depended on the site of the chorioretinal scar. We advocate pars plana vitrectomy as the method of choice for tractional retinal detachment following fungal endophthalmitis.

Endophthalmitis↗
PubMed1995

A comparative study of intraocular irrigating solutions: effects on electroretinography readings during closed vitrectomy in humans.

The effects of intraocular irrigating solutions on electroretinography have been extensively studied in animal models, but effects on human electroretinography have not been reported. This study examined the effects of two commercially available irrigating solutions, S-MA2 (Opeguard MA) and DE-057 (BBS-Plus) on 30-Hz flicker electroretinography during closed vitrectomy in humans. Eight eyes of 8 patients were examined. All patients underwent a simple vitrectomy without treatment of proliferative membrane. For 30-Hz flicker electroretinography recording, a contact lens with a built-in light-emitting diode was sterilized and used as both a stimulus source and a recording electrode. Replacing S-MA2 with DE-057 decreased the electroretinography amplitude from 55.8 +/- 15.2 to 45.5 +/- 13.2 microV (mean +/- SEM). Changing the irrigation solution from DE-057 back to S-MA2 increased the amplitude from 45.5 +/- 13.2 to 59.9 +/- 17.3 microV. However, these changes were not statistically significant. Replacing S-MA2 with DE-057 significantly increased the peak time from 50.1 +/- 1.5 to 57.6 +/- 1.3 msec (p < 0.001). This change was reversible; after changing from DE-057 back to S-MA2, the peak time of flicker electroretinography significantly decreased from 57.6 +/- 1.3 to 49.0 +/- 2.1 msec (p < 0.01). Thus intraoperative 30-Hz electroretinography showed delayed peak time during irrigation with DE-057, as compared with S-MA2. The lower potassium concentration and higher glucose concentration of S-MA2, as compared with DE-057, may be the cause of such electroretinography changes.

Aged↗
PubMed1995

Effects of adenosine on chick retinal pigment epithelium: membrane potentials and light-evoked responses.

We examined the effects of adenosine, a putative mediator of neuroprotection during cerebral ischemia, on the electrophysiological characteristics of retina-retinal pigment epithelium-choroid preparations obtained from 1-7 day-old chick and maintained in vitro. Our experiments produced the following results. First, superfusion of the retinal surface with adenosine (0.1 mM) increased the trans-tissue potential. The trans-epithelial (but not the trans-retinal) potential was also increased to the same magnitude with a time-course similar to that of the trans-tissue potential. Second, adenosine produced a depolarization of the epithelial basal plasma membrane with a concomitant decrease in its basal membrane resistance. Third, the trans-epithelial (but not the trans-retinal) c-wave in response to a light stimulus was augmented by adenosine. Adenosine reduced the hyperpolarization of the epithelial basal membrane, but had no effect on the extracellular concentration of K+ in the subretinal region. Fourth, the light-peak that was elicited with a 300 s light stimulus was also depressed by adenosine. Fifth, when 4,4'-diisothiocy anostilbene-2,2'-disulfonate (DIDS), a relatively selective inhibitor of Cl- channels, was perfused at 50 microM on the choroidal surface, adenosine-induced increases in the trans-tissue potential and the c-wave were both abolished. These results suggest that adenosine increased the Cl- conductance of the basal plasma membrane of the retinal pigment epithelium and thereby augmented the standing potential as well as the light-elicited membrane potentials of the retinal pigment epithelium, which seems to be involved in the pathophysiology of retinal ischemia.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1995

Thallium-201 uptake in eosinophilic granuloma of the frontal bone: comparison with technetium-99m-MDP imaging.

An 11-yr-old female presented with a 6-wk history of left upper lid tenderness and left eye lacrimation. Left lateral supraorbital mass and left preauricular lymph node were the only significant physical examination findings. On skull x-ray, a left frontal bone defect was noted. CT and MRI showed a soft-tissue mass in the area of the bone defect. Bone scintigraphy exhibited peripheral uptake within the central photon deficient area. With 201TI SPECT, high uptake was noted on early and delayed images. Diagnosis of eosinophilic granuloma was performed by biopsy. Since thallium uptake was seen in the area where photon deficiency was exhibited by 99mTc-MDP scintigraphy, we speculate that thallium SPECT could detect eosinophilic granuloma when radiographic skeletal survey or radionuclide bone scan are equivocal. It could also rule out multiple bone involvement and recurrence or regrowth after therapy.

Child↗
PubMed1994

[New development of cellulose-ferric ammonium citrate solution as a contrast-enhancement agent for magnetic resonance imaging of esophageal diseases].

For magnetic resonance imaging (MRI) of esophageal diseases, we have developed a new contrast-enhancement agent, cellulose-ferric ammonium citrate solution. Using this agent, the esophageal lumen is easily identified. This agent is expected to play a role in the MRI diagnosis of esophageal cancer and to help determine the indications for radical surgery and/or intracavitary irradiation.

Aged↗
PubMed1994

[Interferon-induced retinal changes].

Fifty patients treated with interferon for chronic type C hepatitis, chronic type B hepatitis and renal cell carcinoma were examined for retinal complications. Retinal hemorrhages or cotton wool spots were observed in 23 (46%) of the patients. Retinal hemorrhages without cotton wool spots were found in 14 patients, cotton wool spots without retinal hemorrhages in 5 patients, and both hemorrhages and cotton wool spots in four patients. These findings were potentially reversible. There was one case of branch retinal artery occlusion and one case with microaneurysm. Red blood cell count decreased significantly in the patients with retinopathy compared with those without retinopathy (p < 0.05%). Patients with diabetes, hypertension, retinal arterial sclerosis, and anemia were at risk for retinopathy.

Carcinoma, Renal Cell↗
PubMed1994

[An evaluation of the hemodynamics in metastatic liver tumor by using ultrasound color Doppler flow mapping examination].

Eighty-one patients with metastatic liver tumors were studied by ultrasound color Doppler flow mapping examination. Primary origins consisted of gastric (19 cases), colorectal (40 cases), breast (7 cases), pancreatic (3 cases), gallbladder (3 cases) cancers and the others (9 cases). Metastatic lesions originated from breast, gastric and colorectal cancers had higher detection rates, however no blood flow could be observed within metastatic liver cancers from pancreatic and gallbladder cancers. There were no differences among the maximum blood flow velocity (Vmax), the resistance index (RI) and the pulsatile index (PI) in various metastatic liver tumors. In case of colorectal cancers, metastatic lesions originated from moderately differentiated adenocarcinoma had significantly lower RI (p < 0.05) and PI (p < 0.01) than that from well differentiated adenocarcinoma. In conclusion, ultrasound color Doppler flow mapping examination is a useful method for evaluation of the blood flow within metastatic liver tumors and could offer the histological differentiation of the primary origins, in case of metastatic liver cancers originated from colorectal cancers.

Adult↗
PubMed1994

[Effect of intraocular irrigating solution on flicker electroretinogram during cataract surgery in humans].

We studied the effects of intraocular irrigating solutions on the 30Hz flicker electroretinogram (ERG) during extracapsular cataract surgery in 45 eyes of 35 patients. The effects of two commercially available irrigating solutions. S-MA2 (Opeguard MA) and DE-057 (BSS Plus) were compared. After irrigation and aspiration (I/A) of the residual cortex with S-MA2, ERG amplitude increased to 111.2 +/- 5.8% of the pre-I/A amplitude. It significantly increased to 116.9 +/- 7.0% at the end of operation (p < 0.05) compared with before I/A. After I/A with DE-057, ERG amplitude increased to 109.5 +/- 5.3% of the pre-I/A amplitude. It significantly increased to 115.7 +/- 6.5% at the end of operation (p < 0.05) compared with before I/A. After I/A with S-MA2, ERG peak time was significantly prolonged to 103.9 +/- 0.8% of the pre-I/A peak time (p < 0.01). It was significantly shortened to 101.5 +/- 0.9% at the end of the operation (p < 0.001) compared with after I/A. After with DE-057, ERG peak time was significantly prolonged to 104.2 +/- 1.2% of the pre-I/A peak time (p < 0.01). It was significantly shortened to 101.3 +/- 1.22% at the end of the operation (p < 0.05). There were no statistical differences between changes of amplitude and peak time with S-MA2 and those with DE-057. We speculated that a drop in the retinal temperature during I/A in the anterior chamber and an increment of the photopic ERG amplitude during light adaptation with the operating microscope caused these ERG changes.

Adolescent↗
PubMed1993

Nursing in Japan.

Explore the source record for details and available documents.

Career Choice↗
PubMed1993

[Effect of intraocular irrigating solution on electroretinogram during pars plana vitrectomy].

The effects of intraocular irrigating solutions on the human retina are not known. We recorded 30 Hz-flicker electroretinograms (ERGs) during vitrectomy, and examined the effects of perfusate S-MA2 and DE-057 on the human ERG. The amplitude of the 30 Hz-flicker ERGs were not significantly different for the two irrigating solutions. The peak latency of the 30 Hz-flicker ERG was increased 14 +/- 4.4% (mean +/- SE) during irrigation with S-MA2, compared with the preoperative peak latency. Replacement of S-MA2 by DE-057 increased the peak latency by 37 +/- 5.8% (p < 0.01). Since the peak latency of the 30 Hz-flicker ERG became shorter after replacement of DE-057 by S-MA2, these effects were reversible (p < 0.01).

Aged↗
PubMed1992

[A study of irradiated spines in radiotherapy--using 99mTc-HMDP bone scintigraphy & MR imaging].

When radiation therapy is performed on a patient with malignant tumor, vertebral spines are sometimes included in the irradiation field. In the present study, 99mTc-HMDP uptake was examined in 102 cases of malignant tumors treated with radiation therapy (irradiated total doses from 10 to 70 Gy) in order to clarify the time course of accumulation. The scintigram on the film was transformed with a film digitizer into objective data, and the Accumulation Decreasing Index (ADI) was calculated each month after irradiation. In the group receiving less than 30 Gy, recovery of 99mTc-HMDP accumulation was seen after a mild decrease in the ADI. However, in the group that received more than 40 Gy, no recovery of accumulation was seen, and a large decrease in the ADI followed. Vertebral MRI was performed with and without Gd-DTPA enhancement to calculate the vertebral Signal Intensity Ratio (SIR), and decreased blood flow in the irradiated bone marrow was estimated from the changes in SIR values. In the irradiated area, no definite abnormal accumulation of 99mTc-HMDP was observed against the new metastatic bone tumor. In such cases, MRI should be performed soon after bone scintigraphy in order to detect the tumor.

Bone Marrow↗