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Biomedical subjects

Y Oguchi

Publications and source records attributed to Y Oguchi.

At least 109 records · Page 6Linked to original sources
PubMed1992

Primary non-AIDS related brain lymphoma. Patterns of failure following radiotherapy.

Thirteen patients with primary brain lymphoma (PBL) were treated with radiotherapy. Three patients also had ocular involvement with retinal masses at initial presentation. All but one patient received conventional whole brain irradiation and, in addition, spinal irradiation, intrathecal methotrexate or orbital irradiation were given in two, two and four patients respectively. The radiation doses for involved sites ranged from 40 to 65 Gy, and for prophylactic sites from 30 to 50 Gy. After radiotherapy, all patients had complete regression of the tumor on computed tomography. Nine patients relapsed, 5 of them with brain recurrence. Two patients had ocular recurrence exclusively as their first relapse. The remaining two relapsing patients had bone lesions. One patient died intercurrently. As a result, only three patients are alive and free of disease after 16 to 36 months and all three received some adjuvant treatment in addition to whole brain irradiation.

Adult↗
PubMed1992

Oxiradical-dependent photoemission induced by a phacoemulsification probe.

Oxygen free radical formation by conventional phacoemulsification devices has been postulated as a possible mechanism of corneal endothelial damage during surgery. To test this hypothesis, phacoemulsification probe-induced free radical production was visualized using a single photon-counting camera and an O(2-)-sensitive luciferin derivative, 2-methyl-6-[p-methoxyphenyl-3,7-dihydroimidazo [1,2-a]pyrazin-3-one (MCLA), which allows the visualization of spatial and temporal alterations in free radical production. Within 1 min after starting ultrasound emission, MCLA-dependent chemiluminescence was increased significantly, the intensity of which was maximal at the tip of the probe and tapered along a gradient toward distal portions. The chemiluminescence was suppressed significantly by adding either superoxide dismutase (300 U/ml) or sodium azide (20 mmol/l). By adding deuterium to the medium, MCLA-dependent chemiluminescence significantly increased, suggesting the involvement of singlet oxygen in the reaction.

Azides↗
PubMed1992

Enhancement of effector cell activities in mice bearing syngeneic plasmacytoma X5563 by a biological response modifier, PSK.

We investigated the effect of PSK, a protein-bound polysaccharide obtained from Coriolus versicolor of basidiomycetes, on antitumor immunity in tumor-bearing mice. PSK prolonged significantly the life span of C3H/He mice bearing syngeneic plasmacytoma X5563 in a schedule- and dose-dependent manner. PSK was most effective when administered at 100 mg/kg every other day ten times starting from the day after tumor inoculation. The administration of PSK enhanced significantly the cytostatic activity of peritoneal exudate plastic-adherent cells and the cytolytic activity of spleen cells after in vitro incubation with mitomycin C-treated tumor cells. In addition, PSK restored the cytokine-producing capacity of spleen cells suppressed in tumor-bearing mice after in vitro incubation with mitogen. Sera from tumor-bearing mice suppressed the activity of such effector cells as well as the interleukin 2-producing capacity of spleen cells, but sera from PSK-treated tumor-bearing mice prevented this suppression. These results suggest that PSK enhances antitumor immunity by reducing immunosuppressive activity of serum from tumor-bearing mice.

Adjuvants, Immunologic↗
PubMed1991

Purification of a kininogenase (kininogenase-2) from the venom of Agkistrodon caliginosus (Kankoku-Mamushi).

From the partially purified capillary permeability-increasing enzyme obtained from A. caliginosus venom, another kininogenase (kininogenase-2) was purified by gel filtration on Sephadex G-100 and ion-exchange chromatography on CM-Sephadex C-50, DEAE-Sephadex A-50, S-Sepharose Fast Flow and Q-Sepharose Fast Flow. The purified enzyme was homogeneous by polyacrylamide gel electrophoresis at pH 8.3 and SDS-gel electrophoresis. The kininogenase-2 had arginine ester hydrolytic and capillary permeability-increasing activities, and did not show any caseinolytic or clotting activity in a similar manner to a previously purified kininogenase (kininogenase-1). The purified kininogenase-2 liberated bradykinin on incubation with purified bovine high mol. wt kininogen. The rate of bradykinin release from the kininogen by kininogenase-2 was slower than that by the kininogenase-1, although both enzymes rapidly cleaved the peptide bonds in the kininogen molecule.

Amino Acid Sequence↗
PubMed1991

Mitochondrial DNA analysis of Leber's hereditary optic neuropathy.

A mitochondrial DNA (mtDNA) mutation associated with Leber's hereditary optic neuropathy (LHON) was recently observed. The presence or absence of the mutation was analyzed in 10 Japanese patients whose clinical course and fundus findings were consistent with LHON. Four of them had at least one maternally related individual who also had bilateral optic atrophy, and were diagnosed as "definite LHON". The other 6 cases lacked any record of optic nerve disease in maternally related individuals, and were diagnosed as "possible LHON". We found the mutation at the SfaNI site of mtDNA in 3 out of the former 4 cases, and in 5 out of the latter 6 cases. This result demonstrates the clinical and diagnostic importance of mtDNA analysis, especially with possible cases of LHON, and suggests that an alternative mutation associated with LHON is also present in Japanese patients.

Adolescent↗
PubMed1990

Increased canine pancreatic acinar cell damage after organophosphate and acetylcholine or cholecystokinin.

Sublethal doses of organophosphate anticholinesterases cause acute pancreatitis in dogs within 2 h. In vitro studies using canine pancreatic fragments have also demonstrated that the peak of amylase release in response to acetylcholine is shifted far to the left after incubation with the organophosphates echothiophate (10(-4) M) or tetraisopropyl pyrophosphoramide (iso-OMPA) (10(-3) M), indicating an increased sensitivity of response. The present in vitro study examined whether there was also an increased susceptibility to acinar cell damage at the electron microscopic level after acetylcholine or cholecystokinin. Minced pieces of whole fresh canine pancreas 2-3 mm in size were placed in buffered Eagle's solution and gassed with 100% O2. After pretreatment 1 h with echothiophate or iso-OMPA, they were then incubated with acetylcholine (10(-5) M). Other tissues preincubated with echothiophate were stimulated with cholecystokinin (10(-9) M). These are submaximal doses for untreated canine pancreatic fragments. After acetylcholine and echothiophate or acetylcholine and iso-OMPA, there was extensive acinar damage with the appearance of large vacuoles and lakes, and interstitial edema. There was evidence of intense supramaximal stimulation and lateral exocytosis. Similar destructive changes were seen after echothiophate and cholecystokinin. In control sections from tissues stimulated with acetylcholine (10(-5) M) or cholecystokinin (10(-9) M, there were lumenal exocytotic patterns typical of submaximal stimulation. Other controls, organophosphate alone and unstimulated basal conditions, showed only minor changes. It is concluded that the increased sensitivity to acetylcholine after organophosphate incubation correlates with an increased susceptibility to acinar ultrastructural damage from acetylcholine and cholecystokinin.

Acetylcholine↗
PubMed1990

Congenital dilatation of the bile duct in 100 instances and its relationship with anomalous junction.

Congenital dilatation of the bile duct (CDBD) or choledochal cyst has been demonstrated to be associated with an anomalous junction of the pancreaticobiliary ductal system. Multifarious clinical signs and symptoms of CDBD have been shown to be closely related with the presence of this anomalous junction. In the present study, 100 instances of CDBD treated surgically at our institutions during a 30 year period were classified into two types according to the morphologic features of dilatation of the bile duct; there were 77 instances of the cystic type and 23 of the cylindric type. Morphologic features of the lesion, clinical signs and symptoms and laboratory findings in these 100 instances were clinically analyzed. In almost all of the patients who were less than one year of age, the disease was of the cystic type and patients presented with either a palpable mass or jaundice as the main symptom. In patients more than one year of age, the disease was of either the cystic or cylindric type. A history of episodes of characteristic abdominal pain accompanied by elevated levels of serum amylase was present in 70 of the patients with the cystic type of disease and in all of the patients with the cylindric type. Histologic sections from the patients showed glandular formation with chronic inflammation, possibly a result of refluxed activated pancreatic juice; in contrast, histologic sections from the remaining patients of all ages showed only thickening of the fibrous layer. Thus, such variable morphologic features and clinical signs and symptoms in CDBD are highly dependent on two factors--the age at onset and the reflux of pancreatic juice into the bile duct through the common channel.

Abdominal Pain↗
PubMed1990

Competitive action of a biological response modifier, PSK, on a humoral immunosuppressive factor produced in tumor-bearing hosts.

We investigated the effect of PSK, a protein-bound polysaccharide obtained from the basidiomycetes Coriolus versicolor, on an immunosuppressive factor produced in tumor-bearing animals. Oral administration of PSK suppressed the growth of the tumor in C3H/He mice bearing X5563 plasmacytoma or MH134 hepatoma, but affected mice bearing MM102 mammary tumor little. PSK prevented the reduction in splenic lymphocyte blastogenesis caused by phytohemagglutinin that occurs in mice bearing X5563 tumors or MH134 hepatoma. The lymphocyte blastogenesis affected little by tumor or PSK in mice bearing MM102 tumors. The effect of sera on the blastogenesis of lymphocytes caused by phytohemagglutinin was different with different tumors in the C3H/He mice. Serum of mice bearing X5563 tumors inhibited blastogenesis, but serum of mice bearing MH134 hepatoma or MM102 tumors promoted it. The sera of mice bearing MH134 hepatoma contained both inhibitory and promotive factors; those of mice bearing X5563 tumors contained an inhibitory factor, and those of mice bearing MM102 tumors contained a promotive factor. The oral administration of PSK reduced the inhibition caused by the sera of mice bearing X5563 tumors. The promotive activity of sera from mice bearing MH134 hepatoma was augmented by PSK; that of sera in mice bearing MM102 tumors was not affected by PSK. Living Bacillus Calmette-Guérin did not have such effects in any of these mice. Serum immunosuppressive activity was also reduced by PSK in various tumor lines of rodents. These results suggest that PSK acts by reducing the activity of immunosuppressive factors produced in tumor-bearing hosts.

Administration, Oral↗
PubMed1990

[DNA diagnosis of Leber's hereditary optic neuropathy].

The point mutation at nt11778 in mitochondrial DNA is highly associated with Leber's hereditary optic neuropathy and eliminates a restriction enzyme SfaNI site in American blacks and Caucasians. DNA diagnosis was applied to a male Japanese patient with this disorder and his mother as a carrier. The mitochondrial DNA fragments (255bp) including this mutation were amplified by polymerase chain reaction. SfaNI digested the DNA fragments of normal Japanese subjects, but did not digest those of the patient or the carrier, The mutation within the SfaNI site is also associated with Japanese suffering from this disorder.

Adult↗
PubMed1989

Inhibition of acetyl- and butyrylcholinesterase and amylase release from canine pancreas.

There are two tissue-fixed cholinesterases in dog pancreas: acetylcholinesterase and butyrylcholinesterase. In the present experiments, an organophosphate that only inhibits butyrylcholinesterase (isopropylpyrophosphoramide, or iso-OMPA) was compared with echothiophate and a nonorganophosphate compound, physostigmine. The latter two agents inhibit both cholinesterases. Fresh canine pancreas from anesthetized dogs was minced into fragments and suspended in Eagle's solution gassed with 100% O2. Amylase release was measured by the Phadebas method. In 2-h dose-response studies, there was a fivefold increase in sensitivity to acetylcholine when fragments were preincubated 1 h with iso-OMPA. There was a 1,000-fold increase in sensitivity when fragments were preincubated for 1 h in echothiophate. Basal amylase release in incubates with echothiophate were also increased. In dose-response studies with CCK-8, iso-OMPA was without effect, but echothiophate treatment resulted in a greater total response to CCK-8. There was a corresponding increase in basal output with echothiophate alone. Physostigmine also potentiates the response to CCK-8. Cumulative responses up to 3 h with half-maximal acetylcholine or half-maximal CCK-8 doses showed enhanced total output in fragments preincubated with echothiophate (p less than 0.05). The enhancement effect was atropine-sensitive to hexamethonium ganglionic blockade. In calcium-free medium, the enhancement with echothiophate was greatly reduced but still present. Inhibitors of both cholinesterases in the pancreas cause a greater total amylase release to sub-maximal doses of acetylcholine and CCK-8 than agents that only inhibit butyrylcholinesterase. Though our data do not provide direct proof, the results could be explained by a greater accumulation of endogenous acetylcholine when both cholinesterases are inhibited.

Acetylcholinesterase↗
PubMed1989

The influence of aniseikonia on the VEP by random-dot stereogram.

Static random-dot stereograms were employed to evaluate the unequal input between two eyes, both objectively by VEP and psychophysically. In subjects with normal binocular function, different levels of artificial aniseikonia (from 2% to 15%) were established by placing several levels of size lenses in front of one eye. Binocular summation in amplitude in the VEP was observed below 5% aniseikonia, and the binocular inhibition took place above 5% aniseikonia. Psychophysically, perception of stereopsis could be maintained between 3% and 5% aniseikonia, but disappeared above 5% aniseikonia. Electrophysiological findings of binocular interaction caused by aniseikonia corresponded to the psychophysical findings, and stereoscopic perception was obtained only in the case of binocular summation in the VEP. In the present study, the amount of tolerable aniseikonia in order to maintain stereopsis was considered to be below 5%.

Adult↗
PubMed1989

Treatment with Krestin combined with mitomycin C, and effect on immune response.

The combination effects of Krestin (PSK) and mitomycin C (MMC) were examined in experimental tumor models. PSK was administered either orally or intraperitoneally. Delayed-type footpad reaction and antibody formation against sheep erythrocytes were measured in hosts of which immune functions were depressed by tumor burden. Results of the experiment indicated that the simultaneous administration of PSK and MMC significantly increased the survival rate of tumor-bearing mice and restored more effectively their immune functions compared to those of nontreated tumor-bearing controls or tumor-bearing hosts treated with a single agent.

Animals↗
PubMed1989

[Fourier analysis of binocular VEP with stimulation of fusional areas].

Dioptic stimulation, by which each eye was stimulated by the same checkerboard pattern but at different pattern reversal rates, was performed and the visually evoked potentials (VEP) were analyzed with a Fourier processor. When both images from each eye were superimposed using fusional targets and prisms, the intermediate frequency component (IFC) was recognized besides two components corresponding to each stimulating frequency reversal rate. The relationship between IFC and the superimposed area (SA) was studied. IFC appeared clearly when the visual angle of SA was above 60 min. (18% of SA). The amplitude of IFC was saturated at a visual angle of 140 min. (53% of SA). Furthermore, when the SA was 200 min. of the visual angle (100% of SA), the IFC showed 0.6 times the activity of the monocular component. When dioptic stimulation was used, only one component corresponding to the stimulating pattern rates was observed and the amplitude became higher with increase of SA. The amplitude of the SA (areas of each eye were fully superimposed) was 1.4 times greater than that of 0% SA.

Adult↗
PubMed1988

Simultaneous recording of visual evoked potentials and electroretinograms in patients with unilateral opaque media.

We studied the correlation between preoperative visual evoked potentials (VEPs) and postoperative visual acuities in patients with unilateral opaque media. The fellow eye was used as the control. The filtering effect due to opaque media could be assessed on the basis of the difference of the electroretinogram (ERG) threshold in the two eyes. 'Modified VEPs' were then calculated by eliminating the assessed filtering effects, which improved our ability to detect the potential for visual recovery. In the normal eye, the stimulus threshold for VEP is lower than that for ERG by 2 or 3 log units. Therefore should a higher stimulus threshold be found for VEP than ERG, severe optic nerve damage is highly probable in eyes with media opacties.

Electroretinography↗
PubMed1988

Cytotoxic effects of 24R,25-dihydroxycholecalciferol on the proliferation of various tumor cell lines in vitro and its antitumor effects in vivo.

24R,25(OH)2D3, one of the endogenous active metabolites of vitamin D3, showed suppressive effects on the proliferation of various tumor cells in vitro, and showed a suppressive effect on the growth of human osteosarcoma transplanted in nude mice. 24R,25(OH)2D3 increased bone strength lowered by the tumor burden which causes abnormal calcium metabolism and results in hypercalcemia.

Animals↗
PubMed1988

Histopathologic studies of congenital dilatation of the bile duct as related to an anomalous junction of the pancreaticobiliary ductal system: clinical and experimental studies.

Clinical and experimental studies of congenital dilatation of the bile duct as related to an anomalous junction of the pancreaticobiliary ductal system were performed. Epithelial hyperplasia accompanied by round cell infiltration and increased thickness of the wall with fibrosis was observed histologically in the resected bile ducts of all 40 patients. Twenty-two of 26 patients (86.4%) who had bouts of abdominal pain showed that epithelial hyperplasia with round cell infiltration is dominant (glandular type), and 11 of 15 cases (73.7%) with persistent jaundice showed that thickness of the wall with fibrosis is dominant (fibrotic type). Amylase activities in bile of glandular-type cases obtained from the common bile duct intraoperatively were significantly greater than those of fibrotic-type cases (p less than 0.01). The common bile ducts of the canine model, in which whole pancreatic juice passed in the bile duct, dilated cylindrically 3.28 +/- 2.48 times in diameter after 24 to 41 days and histologically showed epithelial hyperplasia with round cell infiltration of the glandular type. These findings suggest that an anomalous junction of the pancreaticobiliary ductal system and the reflux of pancreatic juice into the bile duct affect not only clinical manifestations but also pathologic changes, especially of the glandular type, in patients with congenital dilatation of the bile duct.

Adult↗