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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 109 records · Page 6Linked to original sources
PubMed2001

Autologous blood injection for marked overfiltration early after trabeculectomy with mitomycin C.

PURPOSE: After trabeculectomy with mitomycin C, extremely low intraocular pressure (IOP) with excess filtration may cause hypotonous maculopathy in the early postoperative period. We evaluated the effect of injecting autologous blood on reversing early postoperative marked hypotony after trabeculectomy with mitomycin C. METHODS: Trabeculectomy with mitomycin C was performed in 258 eyes between 1994 and 1998. Peribleb autologous blood injection was performed in five eyes in which pressure patches were ineffective in reversing excess filtration. Approximately 0.1 to 0.3 ml of whole unclotted blood was slowly injected at least 3 mm from the edge of the flap using a sterile 27-gauge needle. RESULTS: None of these eyes developed hypotonous maculopathy after injection. After a mean 31-month follow-up, all eyes had well-controlled IOP and visual acuity in three eyes was much improved. Postoperative complications included mild IOP elevation in one eye treated with laser suturelysis, and fibrinous pupillary membrane in one eye. CONCLUSION: In the early postoperative period, autologous blood injection is effective in reversing excess filtration.

Aged↗
PubMed2001

Phenytoin promotes Th2 type immune response in mice.

The effects of chronic administration of phenytoin, a common anticonvulsive drug, on immune responses were studied in mice. Anti-keyhole limpet haemocyanin (KLH) IgE antibody response after KLH-immunization was enhanced in phenytoin-treated mice. Proliferative responses of spleen cells induced with KLH, concanavalin A (ConA), lipopolysaccharide and anti-CD3 antibody were reduced in phenytoin-treated mice. Accessory function of spleen adherent cells on ConA-induced T cell proliferative response was reduced in phenytoin-treated mice. KLH-induced IL-4 production of spleen cells was enhanced, while IFN-gamma production was reduced in phenytoin-treated mice. In addition, production of IL-1 alpha, but not IL-6 and IL-12 by spleen adherent cells from phenytoin-treated mice was reduced. Natural killer cell activity was reduced in phenytoin-treated mice. These results suggest that phenytoin treatment preferentially induces a Th2 type response. We also observed that plasma ACTH and corticosterone levels were increased in phenytoin-treated mice, and speculated that phenytoin might act directly and indirectly, through HPA axis activation, on the immune system to modulate Th1/Th2 balance.

Adrenocorticotropic Hormone↗
PubMed2001

Overexpression of chlorophyllide a oxygenase (CAO) enlarges the antenna size of photosystem II in Arabidopsis thaliana.

The light-harvesting efficiency of a photosystem is thought to be largely dependent on its photosynthetic antenna size. It has been suggested that antenna size is controlled by the biosynthesis of chlorophyll b. To verify this hypothesis, we overexpressed the enzyme for chlorophyll b biosynthesis, chlorophyllide a oxygenase (CAO), in Arabidopsis thaliana by transforming the plant with cDNA for CAO under the control of the 35S cauliflower mosaic virus promoter. In the early de-etiolation phase, when the intrinsic CAO expression is very low, the chlorophyll a: b ratio was drastically decreased from 28 to 7.3, indicating that enhancement of chlorophyll b biosynthesis had been successfully achieved. We made the following observations in full-green rosette leaves of transgenic plants. (1) The chlorophyll a : b ratio was reduced from 2.85 to 2.65. (2) The ratio of the peripheral light-harvesting complexes (LHCII) to the core antenna complex (CPa) resolved with the green-gel system increased by 20%. (3) The ratio of the light-harvesting complex II apoproteins (LHCP) to 47-kDa chlorophyll a protein (CP47), which was estimated by the results of immunoblotting, increased by 40%. These results indicated that the antenna size increased by at least 10-20% in transgenic plants, suggesting that chlorophyll b biosynthesis controls antenna size. To the best of our knowledge, this is the first report on enlargement of the antenna size by genetic manipulations.

Apoproteins↗
PubMed2001

Physical signs associated with excessive television-game playing and sleep deprivation.

BACKGROUND: To elucidate significance of physical signs seen in excessive television-game (TVG) players complaining of unexplained persistent symptoms, a cross-sectional cohort study was designed. METHODS: A total of 1143 school children, aged between 6 and 11-years-old, and their parents were included in the study. Questionnaires were sent to guardians asking the number of hours that their children watched TV, TVG, and slept. All children were examined to check for three physical signs, black rings in the skin under the eye (BR), muscle stiffness in the shoulder (MS), and displacement of the scapula associated with muscle stiffness in the shoulder (DS/MS) by inspection and palpitation. RESULTS: The three signs, BR, MS and DS/MS, were present in 165 (14.4%), 229 (20.0%) and 72 (6.2%) children, respectively. Boys had greater frequencies of two signs than girls (BR, 19.6% vs 8.9%, P<0.01; MS, 26.1% vs 13.6%, P<0.01), respectively. Boys spent more time on TVG playing than girls (1.1+/-0.7 h/day vs 0.4+/-0.6 h/day, P<0.0001), respectively. Excessive TVG players, who spent > or = 1 h/day for TVG had greater frequencies of two signs, BR and MS, than those of non-TVG-players (18.9% vs 13.0%, P<0.05; 25.6% vs 14.4%, P<0.01), respectively. The TVG playing time correlated with two signs, BR (P=0.0143) and MS (P=0.0048). Furthermore, sleep deprivation related to three signs, BR (P=0.0078), MS (P<0.0001) and DS/MS (P=0.0290). CONCLUSIONS: Excessive TVG playing links to the occurrence of BR and MS. Other factors, which cause sleep deprivation, may underlie in the occurrence of the three signs. The amount of time spent on TVG playing should be regulated to < 1.0 h/day.

Child↗
PubMed2001

Adenoid cystic carcinoma of the prostate: a case report with immunohistochemical and in situ hybridization staining for prostate-specific antigen.

A 43-year-old man with urinary outlet obstruction was referred to our hospital. A digital rectal examination revealed an elastic hard prostate. The serum prostate-specific antigen (PSA), serum prostatic acid phosphate and gamma-seminoprotein levels were found to be within the normal range, and transrectal ultrasound sonography provided normal findings. The patient underwent a subcapsular prostatectomy under a diagnosis of benign prostatic hyperplasia. Histopathologically, the lesion was diagnosed as an adenoid cystic carcinoma of the prostate. Because a further examination revealed a pathologic extension into the urinary bladder, a radical cystoprostatectomy was performed. The expression of PSA protein and PSA mRNA was studied by means of immunohistochemistry and an in situ hybridization technique. The adenoid cystic carcinoma in the patient did not show any positive signs for PSA protein or PSA mRNA.

Adult↗
PubMed2001

Beneficial effect of Helicobacter pylori eradication in dermatologic diseases.

BACKGROUND: A relationship between skin diseases, particularly rosacea and chronic urticaria, and H. pylori infection has been suggested. METHODS: We preformed a prospective evaluation of the effect of H. pylori eradication in patients with a variety of chronic skin diseases. Patients were followed monthly for at least one year after cure of the infection. The effect of therapy was scored using a three point scale: complete remission (> 90% improvement), partial remission (50-90% improvement) or no improvement (< 50 improvement). The relationship between response and anti-H. pylori Ig G and E to specific H. pylori antigens was analyzed by Western blot analysis. RESULTS: Eighty-eight H. pylori-infected patients with skin disease were enrolled. Treatment was successful in 73% of patients with chronic urticaria as 23% (6 of 26) had complete and 50% had partial remission. Sixty-two percent (18 of 29) with pruritus cutaneus had partial remission as well as 30% with prurigo chronica multiformis had complete remission. Western blotting was done on 24 patients with skin disease and a 44K H. pylori antigen was detected by Ig E analysis in 100% (5 of 5) patients with complete remission compared to 23% (3 of 13) in those without skin disease. CONCLUSIONS: These results suggest it may be prudent to test patients with chronic urticaria, prurigo chronica multiformis, pruritus cutaneus, and eczema nummulare for H. pylori infection and to eradicate the infection in those whose test is positive.

Anti-Bacterial Agents↗
PubMed2001

Rosette-forming epithelioid osteosarcoma: a histologic subtype with highly aggressive clinical behavior.

Osteosarcoma shows a variety of histologic patterns. Rarely, this tumor may appear epithelioid, including a rosettelike configuration simulating glands. We retrospectively reviewed 16 cases of osteosarcoma with rosettelike structures treated at the National Cancer Center and Akita University, Japan, from 1972 to 1999. The 16 patients were under 30 years of age, and males were predominant in the sex distribution. The tumors arose primarily in the metaphysis of long tubular bones, and the most common symptom was pain. Roentgenographically, the lesions showed a highly destructive appearance with varying degrees of mineralization. Twelve patients (75%) died of multiple lung metastases in spite of surgery with wide surgical margins and systemic chemotherapy. The estimated cumulative 5-year survival rate was 15%, significantly worse than the rate of 55% in 70 cases of conventional osteoblastic osteosarcoma without rosettelike structures arising in long tubular bones. All of the 16 tumors, originally classified as conventional osteoblastic osteosarcoma, predominantly displayed a small multinodular growth pattern with lacelike osteoid deposits in the center between dilated blood vessels showing a hemangiopericytoma-like appearance. Ten tumors (63%) showed immunoreactivity for epithelial membrane antigen. We believe rosette formation in osteosarcomas of long tubular bones is an ominous sign; therefore, those tumors should be distinguished from osteosarcomas with conventional morphotypes.

Adolescent↗
PubMed2001

Mechanism of retarded liver regeneration in plasminogen activator-deficient mice: impaired activation of hepatocyte growth factor after Fas-mediated massive hepatic apoptosis.

Urokinase-type plasminogen activator (uPA) is implicated in the regulation of hepatic regeneration by activating hepatocyte growth factor (HGF). Here, we investigated its role in the hepatic regeneration after Fas-mediated massive hepatocyte death employing mice deficient in either uPA or its inhibitor, plasminogen activator inhibitor-1 (PAI-1). We measured kinetics of hepatic levels of proliferating cell nuclear antigen (PCNA)-labeling index, plasmin activity, mature HGF, and its phosphorylated receptor, c-Met. In the genetically targeted and wild-type mice, hepatocytes fell into the same extent of apoptosis 6 to 12 hours after an intraperitoneal injection with anti-Fas antibody, as judged from histologic analysis and a histon-DNA enzyme-linked immunosorbent assay (ELISA). In the wild-type mice, mature HGF emerged in the liver 6 hours following anti-Fas injection, and hepatic PCNA-labeling index started to increase following 24 hours and peaked at 48 hours. In the uPA(-/-) mice, emergence of mature HGF was delayed 12 hours and hepatic regeneration peaked at 96 hours. Supplementation with the uPA gene to the uPA(-/-) mice by in vivo lipofection restored hepatic plasmin levels, and improved a delay in the expression of both mature HGF and phosphorylated c-Met, accompanying a normal rate of liver regeneration. In contrast, PAI-1(-/-) mice showed accelerated liver regeneration; mature HGF emerged as early as 3 hours, and PCNA-labeling index increased at 24 hours. This accelerated regeneration was abolished by administration with anti-HGF antibody. These results strongly suggest a physiologic role of uPA in the proteolytic maturation of HGF, and thereby in hepatic regeneration after Fas-mediated massive hepatocyte death.

Animals↗
PubMed2001

Mesangial proliferative glomerulonephritis with deposits of anti-nicotinic acetylcholine receptor antibody in a patient with myasthenia gravis.

A patient with myasthenia gravis developed nephrotic syndrome 3 years after thymectomy. The kidney biopsy specimen revealed mesangial proliferative glomerulonephritis with immune deposits. The glomerular mesangial cells and tubular epithelial cells were sensitive to alpha-bungarotoxin (alpha-BT), a ligand for nicotinic acetylcholine receptor (nAChR), and the binding was inhibited by native alpha-BT, as well as other nAChR ligands, nicotine and d-tubocurarine. In addition, FITC-alpha-BT-neuromuscular junction complexes could also bind to the mesangial cells, and preincubation with unlabeled nAChR inhibited the binding. These findings are consistent with the notion that both nAChR-like protein and anti-nAChR antibody are present in t he mesangial cells of the patient. Although the pathogenetic role of anti-nAChR antibody on the development of glomerulonephritis is unclear, the present observations provide an important insight into the autoimmune-mediated pathophysiological relationship between myasthenia gravis and mesangial proliferative glomerulonephritis.

Adult↗
PubMed2001

Changes in esophageal variceal pressure after transcatheter arterial embolization for hepatocellular carcinoma.

BACKGROUND AND STUDY AIM: The aim of this study was to investigate the influence of transcatheter arterial embolization on esophageal variceal pressure and portal hemodynamics. PATIENTS AND METHODS: Out of 18 cirrhotic patients with hepatocellular carcinoma, 12 underwent transcatheter arterial embolization and the remaining six patients underwent angiography alone as a control. We examined esophageal variceal pressure with an endoscopic pneumatic pressure sensor and portal blood flow with Doppler ultrasonography immediately before and 3 days after transcatheter arterial embolization or angiography. RESULTS: Angiography alone did not influence esophageal variceal pressure or portal blood flow. Transcatheter arterial embolization resulted in an increase in variceal pressure in five (42%) of the 12 patients and in a marked increase in portal blood flow in eight (88.9%) of nine patients, although no change in the endoscopic variceal findings was observed after transcatheter arterial embolization. The change in esophageal variceal pressure did not correlate with the change in portal blood flow. We could not find predictive factors for the elevation of variceal pressure after transcatheter arterial embolization. CONCLUSION: Our study demonstrated that transcatheter arterial embolization resulted in an increase in esophageal variceal pressure in about half of the patients, bearing little relation to portal hemodynamic parameters.

Aged↗
PubMed2001

Duodenal erosions after eradication of Helicobacter pylori infection.

BACKGROUND: There is interest in the development of GERD after Helicobacter pylori eradication. In contrast, the development of duodenal erosions after therapy has received scant attention. Patients were examined after eradication of H pylori infection to determine the frequency of post-therapy duodenal erosions (primary outcome) and whether there was a relation between development of duodenal and esophageal erosions. Additionally, factors were searched for that would identify patients at increased risk for duodenal erosions. METHODS: A single-center, endoscopist-blinded, observational study was conducted of 196 patients in whom H pylori was eradicated. The presence of esophageal or duodenal erosions was evaluated 4 weeks and 6 months after eradication. Serum gastrin and pepsinogen I (PG I) and II (PG II) levels were also determined for 83 patients entering the study during its final year. RESULTS: Multiple small duodenal erosions developed in 8.6% of patients after H pylori eradication and were more common in patients with pre-eradication duodenal ulcer (27.8%) compared with those with gastric ulcer (6.7%) or atrophic gastritis (1.4%) (p < 0.05). Duodenal erosions were associated with high levels of PG I before and after eradication. The frequency of duodenal erosions decreased over time (3.1% by 6 months). CONCLUSION: Duodenal erosions occur after H pylori eradication and appear to be related to duodenal ulcer and increased PG I levels, both of which are associated with increased acid secretion. Measurement of PG I may help to identify patients who have duodenal erosions develop after H pylori therapy for studies of the pathogenesis of these lesions.

Duodenal Ulcer↗
PubMed2001

Circadian change of adenylate cyclase activity in rabbit ciliary processes.

PURPOSE: To characterize in vivo changes of adenylate cyclase activity in rabbit ciliary processes during the circadian cycle. METHODS: After removal of vitreous, lens, retina and choroid from freshly enucleated rabbit eyes, the anterior segment and attached sclera was chilled in cold buffer containing the non-selective phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX). Then ciliary processes were excised and homogenized in ice cold trichloro-acetic acid (TCA) 2.5 min after IBMX treatment. Increased cyclic AMP in response to PDE inhibition was measured in ciliary processes at six times during the circadian cycle, after preganglionic section of the cervical sympathetic trunk (decentralization, DX), and after topical instillation of hydroxyamphetamine, timolol, brimonidine, rauwolscine or a soluble derivative of forskolin. RESULTS: The increase of rabbit ciliary process cyclic AMP levels in response to PDE inhibition with IBMX was enhanced at night. Much of the enhanced nocturnal increase persisted in constant dark and was blunted by DX. Topical instillation of hydroxyamphetamine enhanced the increase during the day; whereas, timolol, a beta-adrenergic antagonist, or brimonidine, an alpha2-adrenergic agonist, blunted the IBMX induced increase. Neither instillation of rauwolscine, an alpha2-adrenergic antagonist, nor the soluble forskolin derivative enhanced the increase of cyclic AMP after IBMX. CONCLUSIONS: The technique reported here can be used to estimate ciliary process adenylate cyclase activity in vivo. There is a circadian rhythm of adenylate cyclase activity in rabbit ciliary processes that is driven in part by ocular sympathetic input and stimulation of beta-adrenergic receptors.

1-Methyl-3-isobutylxanthine↗