Biomedical subjects
Publications and source records attributed to K Masuda.
A 43-year-old non-cirrhotic woman suffered from encephalopathy caused by an extrahepatic portosystemic shunt between the ileal vein and inferior vena cava via the right gonadal vein. Percutaneous transcatheter embolization with stainless steel coils was performed by the retrograde systemic venous approach. Encephalopathy improved dramatically.
We studied the production of heterophile antinuclear antibodies (ANAs) in the sera of 50 patients, 20 with nasopharyngeal carcinoma (NPC) and 30 with other head and neck cancers (laryngeal cancer and maxillary cancer), before and after radiation therapy. A higher incidence of ANAs was found in the sera of patients with NPC and ANA production in these patients was higher after radiation therapy. We therefore performed in vitro experiments to explore the mechanisms of ANA production in the serum of postirradiated NPC patients. X-ray-irradiated NPC-derived cells (NPC-KT) produced a large amount of Epstein-Barr virus (NPC EBV) compared with non-irradiated NPC-KT cells. Nasopharyngeal carcinoma EBV-infected lymphocytes produced high levels of ANAs. These data suggest that lymphocytes infected by EBV from NPC cells may produce ANAs in the sera of NPC patients.
A 34-yr-old man with a liver mass was referred to the hospital. The mass showed temporary spontaneous regression during the follow-up, however, subsequent regrowth of the tumor prompted surgical resection. The specimen revealed intrahepatic cholangiocarcinoma with two distinct components which had been clearly demonstrated on serial CT. Spontaneous resolution of a lesion does not necessarily suggest the lesion's benign, self-limiting entity. Intrahepatic cholangiocarcinoma should be included in the tumors that could spontaneously regress.
We present a case of pituitary hypertrophy due to juvenile primary hypothyroidism with subsequent return to normal size after therapy. This clinical entity is well known, but there are few reports on its magnetic resonance (MR) findings. We stress the usefulness of Gadolinium-DTPA-enhanced (Gd-DTPA-enhanced) MRI in the differential diagnosis of pituitary hypertrophy and pituitary adenoma.
Ten patients with dural carotid-cavernous fistulas (CCFs) who presented with ophthalmic manifestations were studied using postcontrast computed tomography (CT), magnetic resonance imaging (MRI), and selective cerebral arteriography. The lesions of two patients were bilateral. An enlarged cavernous sinus (CS) was diagnosed in 6 of the 12 involved sides using postcontrast CT. An abnormal flow void in the CS was detectable in 11 of the 12 using MRI. A dilated superior ophthalmic vein (SOV) was demonstrated in all of the involved sides by postcontrast CT, and in 9 of the 12 by axial MRI. Thus, both postcontrast CT and MRI are relatively useful and complementary in the diagnosis of dural CCFs. Patients should be followed with selective cerebral arteriography for definitive diagnoses and for therapeutic planning.
We detected 23 intracranial lipomas using MRI. Among them were nine pericallosal lipomas, six lipomas at the dorsal surface of the midbrain, and eight in other locations. In this paper, six lipomas at the dorsal surface of the midbrain were analyzed. Five of these lipomas were in the quadrigeminal cistern and one in the left-sided quadrigeminal cistern. Excluding the smallest lipoma, five of the six lipomas had irregular margins and were broadly based on the surface of the midbrain. In these five cases, deformities of the brain parenchyma were observed adjacent to the lipomas. A mildly dilated ventricular system was observed in one of the largest lipomas in a quadrigeminal cistern. Based on their characteristic shapes and locations, we termed them "dorsal mesencephalic lipomas." Thus, the two preferential sites of intracranial lipomas were pericallosal and dorsal mesencephalic.
The magnetic resonance images of 16 patients with intradural-extramedullary spinal tumors, consisting of 11 neurinomas and five meningiomas were reviewed. The neurinomas appeared hypointense compared to the spinal cord on unenhanced T1-weighted images (T1WI) in nine of 11 patients, and hyperintense on T2-weighted images (T2WI) in nine of 11 patients. Neural foraminal extension was present in two cases. All 10 neurinomas were markedly enhanced; six of them exhibited ring-like enhancement on Gadolinium-DTPA (Gd-DTPA)-enhanced T1WI. The meningiomas appeared isointense on unenhanced T1WI in four of five patients and on T2WI in three of four patients. Three meningiomas showed moderate homogeneous contrast enhancement after the intravenous administration of Gd-DTPA. It is concluded that careful scrutiny of magnetic resonance images facilitates the differential diagnosis of spinal neurinomas and meningiomas.
Thirty-two patients with liver cirrhosis underwent cerebral magnetic resonance imaging (MRI) to evaluate clinical and subclinical portal-systemic encephalopathy (PSE). Symmetrically hyperintense globus pallidi were observed on T1-weighted images in all 11 patients with PSE and in 15 of the 21 patients with PSE. This abnormality was classified as grade I (bilateral globus pallidi with mild to moderate hyperintensity relative to white matter), and grade II (marked hyperintensity bilaterally in the globus pallidi with mildly increased signal intensities in the surrounding structures). Portal-systemic collateral vessels were demonstrated in 23 of 24 patients who underwent abdominal angiography. In 18 of the 19 patients with abnormal MRI, collateral vessels were supplied by the superior mesenteric vein with or without the splenic vein, including four patients with collaterals which were less than 10 mm in diameter. We concluded that hyperintense globus pallidi on T1-weighted images are significant manifestations of clinical PSE. When portal-systemic collaterals supplied by the superior mesenteric vein are observed, even if they are of small diameter, cerebral MRI should be performed to evaluate for subclinical PSE.
Using two 1.5-T magnetic resonance (MR) scanners, 82 venous angiomas (VAs) were imaged. There were 13 (16%) VAs associated with hemorrhagic lesions. Ten of the 13 hemorrhagic lesions were considered hematomas in the subacute or chronic stage, caused by VAs or coexisting cavernous hemangiomas. Two of the 13 were subacute intracerebral hematomas; the remaining one was a sequela of a hemorrhagic venous infarct. After analysis of our data, it was concluded that infratentorial VAs and deeply draining supratentorial VAs in relatively young adults, especially females, are relatively frequently associated with intracerebral hemorrhagic lesions. MR imaging proved useful for diagnosing VAs and associated hemorrhagic lesions.
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PURPOSE: To evaluate short wavelength light-induced retinal damage in rats. METHODS: Pigmented rats were exposed to 300-500 nm wavelength light for 30 seconds, 1, 3, 10, 20, 60, or 90 minutes. Electroretinogram a-, b-, and c-waves were recorded 48 hours after the exposure. RESULTS: While the a- and b-wave amplitudes were reduced significantly after exposures of 60 minutes and longer, the c-wave amplitude was reduced after only 3 minutes of exposure. CONCLUSIONS: Rat retinal pigment epithelium is more sensitive to damage by exposure to 300-500 nm wavelength light than the neural retina.
We assessed the function of Endothelin-1 (ET-1) in the development of anterior chamber inflammation in pigmented rabbit eyes. After the injection of ET-1 solution (10(-13), 10(-11), 10(-9), or 10(-7) M, diluted with 300 microL of artificial aqueous humor) into the anterior chamber, the aqueous protein concentration (APC) increased significantly in a dose-dependent fashion. Peak effects were observed 1-2 hours posttreatment. The APC returned to normal 12 hours after the injection. Pretreatment with antiprostaglandin agents, topical indomethacin, or intravenous diclofenac sodium suppressed the increase in APC. In an endotoxin-induced experimental uveitis model, the ET-1 concentration in the aqueous humor was significantly higher than in normal controls, as was the plasma ET-1 level. These results suggest that ET-1 is an important mediator in ocular inflammatory reactions via arachidonic acid cascade.
We studied histologically the protective effect of alpha-tocopherol to retinal light damage. After 3-week-old albino rats were fed with an alpha-tocopherol deficient or supplemented diet and kept in a 12-hour dim light/12-hour dark environment for 8 weeks, each animal was exposed to intense light (2500 lux) for 1, 3, 6, 12, 24, and 72 hours. The eyes were enucleated and prepared for transmission electron microscopy study and image analysis of phagosomes. Before light exposure, the alpha-tocopherol content of the neural retina of the deficient and supplemented groups was 0.3 microgram and 23.34 micrograms, respectively. After 1- and 3-hour exposures, morphological changes in the retinal pigment epithelium and photoreceptor membranes were more extensive in the deficient group than in the supplemented group. After a 24-hour exposure, pyknotic photoreceptor nuclei were more numerous in the deficient group than the supplemented group. After 3-, 6-, and 12-hour exposures, large phagosomes were more numerous in the deficient group than in the supplemented group. These findings suggest that alpha-tocopherol can protect the retina from light injury for up to 24 hours of exposure.
Endotoxin-induced uveitis (EIU) is an animal model of ocular inflammation induced by lipopolysaccharide (LPS). The lipid A (LA) region of the LPS chemical structure is believed to be responsible for virtually all the biological activities induced by LPS. The aim of this study was to perform a more detailed investigation of the potency of LA in reproducing EIU. Various doses of either LPS or LA were injected into the footpad of an inbred strain of Lewis rat and the inflammation patterns were compared by assessing the protein concentration, by cytological study, and by determining the inflammatory cell content in samples of aqueous humor obtained during 96-hour follow-up. Evaluation of the cell number and protein concentration ratio of both groups showed the LA-stimulated group presented a higher ratio than the LPS group (Welch's t-test, (P < 0.00001). It was noteworthy that even the injection of high doses of LPS could not reproduce the level of cellular infiltration induced by LA. Histological study confirmed the enhanced cellularity in the LA group, neutrophils being predominant in both the LPS- and the LA-stimulated groups. The divergent findings in these two models of uveitis may be valuable to further investigations of the process of inflammatory cell migration into the anterior chamber of the eye.
A fifth annual survey was carried out by mail in February 1997 to investigate the current trends in cataract and refractive surgery in Japan. A questionnaire was sent to 867 ophthalmologist members of the Japanese Society of Cataract and Refractive Surgery. Data received from 440 (50.7%) of the recipients were cross-analyzed and compared with those from the previous surveys. For cataract surgery, there have been trends toward more surgical procedures performed by a surgeon, shorter period of hospitalization, and increased number of outpatient surgery. Ninety percent of respondents preferred phacoemulsification, 42% employed the self-sealing wound closure technique, and 26% used topical anesthesia for phacoemulsification. As for refractive surgery, surgeons remained rather conservative, with 26% and 6% of surgeons doing astigmatic keratotomy and refractive keratotomy, respectively.
Human leukocyte antigens (HLA) were analyzed among Japanese leprosy patients to identify any possible determinants in the development of episcleritis in leprosy patients. Seventy-nine Japanese leprosy patients (33 patients with history of episcleritis and 46 patients without episcleritis) and 114 healthy control subjects were investigated. Human leukocyte antigen-class I and class II specificities were determined serologically by the standard microcytotoxicity test. The HLA-DRB1, -DRB5, -DQA1, and -DQB1 genotypings were performed by using the polymerase chain reaction (PCR)-single strand conformation polymorphism and PCR-restriction fragment length polymorphism analyses. The frequency of HLA-Cw3 was significantly increased among the patients with episcleritis (66.7%) compared to patients without episcleritis (43.5%; odds ratio = 2.6, P < 0.05). The frequency of HLA-DR4 was significantly decreased among the patients with episcleritis (15.2%) compared to patients without episcleritis (39.1%; odds ratio = 0.28, P < 0.05) and the controls (46.5%; odds ratio = 0.21, P < 0.001). At the genomic level, frequencies of the HLA-DRB1*0405, -DQB1*0401, and -DQB1*0302 alleles were significantly decreased among the patients with episcleritis (0%, 0%, and 6.1%, respectively) compared to patients without episcleritis (15.2%, 13.0%, and 26.1%, respectively; odds ratio = 0.07, 0.09, and 0.18, P < 0.05). HLA-DRB1*0405 and -DQB1*0401 were also significantly decreased among the patients with episcleritis compared to the controls (29.8% and 29.8%; odds ratio = 0.04, P < 0.0001). Our results suggest that HLA-Cw3 antigen confers the susceptibility to the development of episcleritis among Japanese leprosy patients. Concurrently, the DRB1 (the -DBR1*0405), and/or DQB1 (the -DQB1*0401 and -DQB1*0302) alleles might provide protection against leprous episcleritis.
Severe, white sheathing of the retinal vessels and yellowish-white placoid lesions, suggesting frosted-branch angiitis, were found in both fundi of a 24-year-old woman. Fluorescein angiography showed hypofluorescence of the placoid lesions in the early phase and hyperfluorescence in the late phase. Indocyanine green angiography showed hypofluorescence during all phases. These findings imply an occlusion of the choriocapillaris. Fluorescein angiography also showed occlusion of the peripheral retinal vessels. With systemic corticosteroids and prostaglandin I2 derivative, the fundi recovered almost completely to normal 3 months later.