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Biomedical subjects

A Hirakata

Publications and source records attributed to A Hirakata.

At least 19 recordsLinked to original sources
PubMed2001

Evaluation of retinal damage induced by air/fluid exchange using a trypan blue inclusion test in rabbits.

PURPOSE: To investigate whether retina damaged in the process of air/fluid exchange could be visualized in situ using trypan blue staining. METHODS: Vitrectomy and air/fluid exchange with continuous air infusion for various periods of time was performed in adult pigmented rabbits, followed by injection of 0.4% trypan blue solution into the vitreous cavity. Retinal staining was evaluated intraoperatively under the operating microscope and by light microscopy after enucleation. RESULTS: Intraoperative examination showed localized trypan blue staining of areas of the retina opposite the infusion cannula. Light microscopy of the same areas revealed intranuclear trypan blue inclusion in the retina. CONCLUSION: Trypan blue staining allows for the immediate in situ evaluation of damage to the retina associated with air/fluid exchange and continuous air infusion in rabbit eyes.

Air↗
PubMed2001

Reconstruction of the portal vein using a peritoneal patch-graft.

BACKGROUND: Reconstruction of the portal vein with autologous veins requires extra incisions. Prosthetic material is associated with an increased risk of infection. We therefore created an animal model of portal vein reconstruction using the peritoneum. METHODS: A 2.5 x 2.5 cm piece of the peritoneum was resected from Landrace pigs weighing 30 to 40 kg and was dipped in 100% alcohol for 10 minutes. The anterior wall of the portal vein measuring 1.2 x 0.6 cm was resected. The peritoneal patch-graft fitting the defect of the portal vein was used to repair it. RESULTS: All 7 pigs survived the surgery, and were killed at 2, 7, 7, 14, 21, 35 and 49 days, respectively, after surgery. There was no evidence of thrombosis or obstruction of the reconstructed portal vein or any other complications. Complete endothelialization of the patches were noted at day 14. CONCLUSIONS: Our patch-graft technique using the peritoneum is considered to be a good and safe alternative for reconstruction after partial resection of the portal vein in clinical surgery.

Animals↗
PubMed2001

Celiac artery aneurysm: a case evaluated preoperatively with three-dimensional computed tomographic angiography.

In a 63-year-old woman computed tomography (CT) incidentally detected a celiac artery aneurysm approximately 3 cm in diameter. While conventional angiography suggested that the splenic artery and common hepatic artery arose from the celiac artery aneurysm, three-dimensional CT angiography indicated that the aneurysm involved only the mid portion of the celiac artery. Considering the risk of eventual aneurysm rupture, surgery was performed. Aneurysmectomy and devascularization of hepatic, splenic, and celiac arteries were carried out following complete cross-clamping of the celiac artery. The distal segment of the celiac artery was directly anastomosed to the proximal segment in an end-to-end fashion. Histologically, the aneurysm wall showed atheromatous changes. Contrast-enhanced abdominal CT confirmed complete removal of the celiac artery aneurysm, and postoperative angiography confirmed good arterial flow. The patient recovered uneventfully after surgery, with normalization of transiently abnormal hepatic function parameters. In this case of celiac artery aneurysm, three-dimensional CT angiography was found to be valuable in determining the relationships of the aneurysms to important arterial branches.

Aneurysm↗
PubMed2001

Liver cell adenoma in a 26-year-old man.

This is a report of a case of liver cell adenoma (LCA) in a 26-year-old man with no prior history of liver disease or glycogen storage disease and no record of hormonal therapy. He was found to have an asymptomatic hepatic mass during a routine medical examination. The physical findings were unremarkable, and the results of routine laboratory studies were all within normal limits. Selective hepatic arteriography showed a hypervascular mass within the right lobe of the liver. Despite the radiological examination, the nature of the mass was unknown, and preoperative biopsy was unadvisable because of the risk of bleeding. Because of the difficulty of determining the malignancy of the hepatic tumor preoperatively, elective laparotomy for diagnosis and hepatectomy as treatment appeared to be the best available approach. Pathological examination of the surgical specimen resulted in a diagnosis of LCA. A review of the literature revealed that LCA unassociated with the use of oral contraceptives is rare.

Adenoma, Liver Cell↗
PubMed2001

[A case of choroidal hemangioma with bullous exudative retinal detachment treated successfully by transpupillary thermotherapy].

BACKGROUND: Choroidal hemangioma associated with bullous retinal detachment may be difficult to treat, due to varying results with conventional laser photocoagulation, radiotherapy, or surgical drainage. Here we report on a case of extensive bullous retinal detachment secondary to circumscribed choroidal hemangioma that was resolved after combined treatment with vitrectomy, silicone oil tamponade, and transpupillary thermotherapy. CASE: A 29-year-old woman presented with a large choroidal hemangioma in her right eye associated with serous retinal detachment. The tumor measured 8 disc diameters in size and was located in the inferotemporal macula, abutting the fovea. RESULTS: Laser photocoagulation of the tumor was unsuccessful in inducing absorption of subretinal fluid. Because of progressive bullous retinal detachment, surgery was performed consisting of external drainage of subretinal fluid, vitrectomy, endolaser photocoagulation of the tumor, and silicone oil tamponade. The silicone oil was removed four weeks postoperatively at which time almost complete resolution of the retinal detachment was observed. However, retinal detachment recurred eight weeks later, and transpupillary thermotherapy was then applied to the tumor. By four weeks after transpupillary thermotherapy, total reabsorption of subretinal fluid, visual acuity improvement, and decreased height of the choroidal hemangioma were noted. CONCLUSION: Transpupillary thermotherapy is an effective treatment for serous retinal detachment associated with choroidal hemangioma.

Adult↗
PubMed2000

Ultrasound biomicroscopy for examination of the sclerotomy site in eyes with proliferative diabetic retinopathy after vitrectomy.

PURPOSE: We evaluated the capability of ultrasound biomicroscopy (UBM) to predict fibrovascular proliferation at sclerotomy sites in eyes with postoperative vitreous hemorrhage due to proliferative diabetic retinopathy (PDR). METHODS: Ultrasound biomicroscopy was used for examining the sclerotomy sites in 13 eyes of 11 patients with PDR experiencing postoperative vitreous hemorrhage (PDR group). Thirty-nine sclerotomy sites (all entry sites of each eye) were examined before reoperation, and the UBM images were compared with findings obtained during revision of the vitrectomy. Thirteen eyes of 13 patients undergoing vitrectomy for nondiabetic diseases were used as controls and examined after vitrectomy. RESULTS: The UBM images were classified into the following four categories: A, tent; B, spheroid; C, trapezoid; and N, none. The findings were distributed as follows in the PDR group: category A, 18%; B, 5%; C, 56%; and N, 21 %; and as follows in the control group: category A, 28%; B, 5%; C, 5%; and N, 62%. In the PDR group, 11 of 12 sclerotomy sites disclosing fibrovascular proliferation possessed the trapezoidal image. Mean length of trapezoidal base was 2.49+/-0.97 mm and 1.51+/-0.75 mm in the groups with and without fibrovascular proliferation, respectively (P<0.01). The average relative reflectivity of the trapezoidal image against the sclera was 0.501+/-0.169 in the fibrovascular proliferation group and 0.891+/-0.183 in the fibrous ingrowth group (P<0.01). CONCLUSION: Ultrasound biomicroscopy is useful in detecting fibrovascular proliferation at sclerotomy sites because a large and low-reflecting trapezoidal UBM image is highly correlated to its presence.

Adult↗
PubMed2000

Ultrastructural and immunohistochemical findings in five patients with vitreomacular traction syndrome.

OBJECTIVE: To evaluate pathologic features of vitreomacular traction syndrome (VMT). METHODS: Preretinal membranes removed from five patients during vitreous surgery for VMT syndrome were evaluated by electron microscopy (n = 4) and immunohistochemistry (n = 1). RESULTS: Electron microscopic examination revealed large segments of internal limiting lamina (ILL) in three of the four cases. Other extracellular features included two types of abnormal collagen fibrils, determined to be type I and fibrous long-spacing collagen. The myofibrocyte was the predominant cell type in all cases. Collagen types I, II, and III, as well as glial fibrillary acidic protein and vimentin, were identified by immunohistochemistry. CONCLUSIONS: Epiretinal membranes in eyes with VMT syndrome adhered tightly to the ILL with abnormal collagen and contractile elements that included myofibrocytes.

Aged↗
PubMed2000

[Comparison of scleral buckling and vitrectomy for superior retinal detachment caused by flap tears].

PURPOSE: We compared the surgical results of vitrectomy and scleral buckling for uncomplicated superior retinal detachment caused by flap tears. SUBJECTS AND METHODS: Included in the study were 225 phakic eyes of 225 patients undergoing primary surgery from January 1990 to December of 1996 for superior retinal detachment caused by flap tears; all eyes had been followed for longer than six months after surgery. The choice of procedures was based on each surgeon's preference. The cases were evaluated retrospectively and the surgical outcome and the rate of complications compared between the two groups of eyes. RESULTS: Initial and final anatomical success rate were 92% and 100% after each procedure. Redetachment after the first procedure was due to new retinal breaks in 5 eyes, reopening of original breaks in 2 eyes of vitrectomy cases, and malpositioned buckle in 11 eyes of scleral buckling cases. Proliferative vitreoretinopathy occurred in 3 eyes of vitrectomy cases. CONCLUSION: Primary vitrectomy was as successful as scleral buckling for superior rhegmatogenous retinal detachment. Although a high incidence of postoperative cataract formation was a major drawback, vitrectomy had some advantages over to scleral buckling.

Adult↗
PubMed1998

Japanese juvenile retinoschisis is caused by mutations of the XLRS1 gene.

We investigated the XLRS1 gene in Japanese patients with retinoschisis (RS). All exons of the XLRS1 gene were sequenced in 14 males, including a pair of monozygotic twins, from 11 individual families with RS and five of their mothers who are asymptomatic but diagnosed as carriers. Six kinds of missense mutations and a nonsense mutation, including six novel mutations, were detected in all 14 patients and carriers. Mutations in the XLRS1 gene are also responsible for RS in non-Caucasian patients. Most Japanese RS cases are caused by an XLRS1 gene defect. A novel mutation, Glu72Lys, was found in four families, suggesting a common mutation in the Japanese population. Clinical features of RS patients with both the Glu72Lys and Pro193Leu mutations indicate that a genotype-phenotype correlation is not recognized in RS.

Eye Diseases, Hereditary↗
PubMed1998

[Characteristics of retinal detachment in eyes with choroidal colobomas].

We reviewed 6 eyes of 6 patients (1 male and 5 females) with retinal detachment associated with choroidal coloboma. Three of these 6 eyes had visible retinal breaks within or at the margin of the coloboma. In one eye, no retinal breaks were noted before or during vitreous surgery, and shallow retinal detachment was localized in the posterior fundus. One eye with bullous retinal detachment with retinal breaks within the coloboma had been having serous retinal detachment localized in the nasal area close to the optic nerve head. In all of these five eyes; vitrectomy, relaxing retinotomy inside the coloboma close to its edges, and cyanoacrylate retinopexy resulted in successful reattachment of the retina. Schisis-like separation similar to that in pit-macular syndrome was noted in the posterior retinal in one eye which had no visible retinal break. Non-rhegmatogenous retinal detachment may exist in association with choroidal colobomas.

Adolescent↗