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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 397 records · Page 22Linked to original sources
PubMed1999

Chemical mediators in atopic dermatitis: involvement of leukotriene B4 released by a type I allergic reaction in the pathogenesis of atopic dermatitis.

BACKGROUND: The mediators produced from a type I allergic reaction have not yet been able to explain the pathogenesis of atopic dermatitis (AD). OBJECTIVE: The purpose of this study was to elucidate the involvement of leukotriene (LT) B4 produced from a type I allergic reaction in the pathogenesis of AD. METHOD: The release of LTB4 was measured both in vitro, in passively sensitized and antigen-challenged human skin slices, as well as in vivo, in skin chambers on patients with AD. RESULTS: LTB4 was released from in vitro human skin by stimulation of the antigen (54.9 +/- 14.6 pg/g wet weight of skin by antigen challenge and 28.0 +/- 11.1 pg/g in control skin, P <.002). Antigen-specific release of LTB4 and histamine was also observed in vivo in nonlesional skin from the patients with AD by using the skin chamber technique. CONCLUSION: LTB4 release during type I allergic reaction in human skin has been determined in vitro. The released LTB4 possibly contributes to cellular response at the acute inflammatory lesion of AD.

Adolescent↗
PubMed1999

Clinical usefulness of serum matrix metalloproteinase-2 concentration in patients with chronic viral liver disease.

BACKGROUND/AIMS: The production of matrix metalloproteinase (MMP)-2 was reported to be increased in chronically diseased livers. Our aims in the present study were to elucidate the clinical usefulness of the serum MMP-2 concentration in chronic viral liver disease. METHODS: We measured serum MMP-2 concentrations with a sandwich enzyme immunoassay in 62 patients with chronic hepatitis, 35 patients with liver cirrhosis, 55 patients with hepatocellular carcinoma and 24 healthy individuals. The assay detects proMMP-2 and proMMP-2 complexed with tissue inhibitor of metalloproteinase-2, but not active forms of MMP-2. The liver MMP-2 content was also measured in autopsied cirrhotic and non-cirrhotic livers. Gelatin zymography and gel filtration chromatography were carried out using the serum. RESULTS: The serum MMP-2 concentration was significantly increased in the liver cirrhosis and hepatocellular carcinoma patients, but not in the patients with chronic hepatitis. There was no significant difference in the serum MMP-2 level between the liver cirrhosis and hepatocellular carcinoma groups. In the patients with chronic viral liver disease, serum MMP-2 concentration showed the best correlation with the degree of liver fibrosis and with serum hyaluronate level. The zymography of serum showed the majority of MMP-2 in serum exists as a proMMP-2. The chromatography of serum revealed a single peak at the position of about 90 kDa corresponding to an MMP-2 complexed with tissue inhibitor of metalloproteinases-2. The liver MMP-2 content was markedly increased in the cirrhotic livers compared with the non-cirrhotic livers, and was positively correlated with the liver collagen content. When investigating the utility of the serum MMP-2 test for differentiating liver cirrhosis from chronic hepatitis, the utility of serum MMP-2 was equal to that of serum hyaluronate, which is known as the best current test for diagnosing liver cirrhosis. CONCLUSIONS: The serum MMP-2 concentration reflects mainly the amount of proMMP-2 complexed with tissue inhibitor of metalloproteinase-2. The serum MMP-2 level was markedly increased in cirrhotic patients, and may be explained by an overproduction in the cirrhotic liver. In the clinical state, the measurement of serum MMP-2 was as useful a test for diagnosing liver cirrhosis as is the serum hyaluronate level.

Biomarkers↗
PubMed1999

Role of polysialic acid on outgrowth of rat olfactory receptor neurons.

Towards elucidating the role of polysialic acid (PSA) in developing olfactory neuron of the rat, we injected neuraminidase (endo-N) into the olfactory nerve pathway under whole embryo culture, then employed immunohistochemistry to (i) detect expression of highly sialylated neural cell adhesion molecules (NCAM-H) and (ii) identify olfactory neurons via anti-microtubule-associated protein 1B (MAP1B) antibody. Olfactory axonal outgrowth from basal lamina occurred at the 31-somite stage and reached the olfactory bulb primordium at the 42-somite stage, being coincident with the timing and expression of NCAM-H immunoreactivity. Enzymatic removal of PSA by endo-N remarkably affected developmental processes of axonal outgrowth, extension, and pathfinding, i.e. individual axons appeared to have become stuck in the mesenchyme. Results indicate that PSA is critically involved with anti-adhesion cues associated with individual axonal growth during olfactory system development.

Animals↗
PubMed1999

Brain waves following remembered faces index conscious recollection.

At a glance, one can often determine whether a face belongs to a known individual. To investigate brain mechanisms underlying this memory feat, we recorded EEG signals time-locked to face presentations. In the study phase, 40 unknown faces were presented, 20 of which were accompanied by a voice simulating that person speaking. Instructions were to remember the faces with spoken biographical information (R-faces) and to forget the others (F-faces). In the test phase, famous and non-famous faces were presented in a visually degraded manner. Subjects made two-choice fame judgments and priming was observed in the form of faster and more accurate responses for old than for new non-famous faces. Priming did not differ between R-faces and F-faces. In a second experiment, faces were not degraded at test and behavioral responses were made only when faces were presented twice in immediate succession. Brain potentials elicited 300 to 900 ms after stimulus onset from frontal and parieto-occipital scalp regions were larger for R-faces than for F-faces. Recognition tested later was more accurate for R-faces than for F-faces. Because the study-phase manipulation influenced recognition but not priming, we conclude that this procedure succeeded in isolating neural correlates of recollective processing from more automatic uses of face memory as indexed by priming.

Acoustic Stimulation↗
PubMed1999

Identification and characterization of allergens in two species of tuna fish.

BACKGROUND: In countries where fish consumption is high, allergenic reactions to fish are common among patients diagnosed with food hypersensitivity. For tuna fish, allergenic proteins are not known. In addition, it is not known how the tuna fish extracts should be processed to obtain optimal in vitro diagnostic performance and to preserve labile antigens. OBJECTIVE: The aim of this study was to characterize IgE-binding components of Yellowfin and Albacore tuna fish. METHODS: Various tuna fish extract preparations were fractionated by sodium dodecylsulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose and analyzed by using tuna positive patients with different Western blot profiles. The functional activity of the extracts was evaluated by basophil histamine release. RESULTS: Immunoblot analysis showed the majority of patients responding to Yellowfin tuna extract. Inhibition studies using immunoblot analysis and histamine release testing showed a specific protein with a molecular weight of approximately 46 kD that is present in Yellowfin tuna, but absent in Albacore. Only defatted, lyophilized tuna fish extracts were able to induce histamine release from sensitized basophils although IgE-binding components were detected in fresh raw, fresh cooked, and canned tuna fish preparations. CONCLUSION: These studies indicate that patient sera may contain different tuna fish species IgE specific antibodies directed against unique species specific allergens present in Yellowfin and Albacore tuna fish. Possibly, extracts should contain specific allergenic components from both Albacore and Yellowfin to cover the epitope heterogeneity observed in sera from patients developing IgE antibodies against tuna fish.

Allergens↗
PubMed1999

Immunohistochemical investigation of new suppressor oncogene p130 in oral squamous cell carcinoma.

New onco-suppressor gene p130 is one of the Rb family forms and is reported to undergo allelic loss in hepatocellular, prostate, and breast carcinomas; however, no report of p130 has been made in oral tumors. The present study dealt with the expression of p130 and Rb proteins by immunohistochemical staining in oral squamous cell carcinomas (n = 110) and oral mucosa. The site of the carcinomas included tongue (n = 48), gingiva (n = 32), oral floor of the mouth (n = 15), oropharynx (n = 6), buccal mucosa (n = 5), and others (n = 4). Histologically there were 65 well-differentiated carcinomas, 33 moderately differentiated carcinomas, and 12 poorly differentiated ones. Positive staining for p130 and Rb was localized to suprabasal cell layers of the normal oral epithelium. In the oral squamous cell carcinoma, positive staining for p130 and Rb was observed in well-differentiated carcinomas (p130, 66.2%; Rb, 78.5%), more than in poorly differentiated ones (p130, 16.7%; Rb, 50.0%). In immunoelectron microscopic features, p130 protein was localized in the nucleus and mitochondria. The expression of p130 was related to the degree of tumor differentiation as that of Rb. It is suggested that p130 gene may be associated with the development of a wide variety of human malignancies rather than the progression.

Adult↗
PubMed1999

A case of lymphocytic infundibuloneurohypophysitis: histophathological studies.

A 57-year-old woman presented with 2-year history of polyuria and polydipsia. Hormonal studies revealed almost normal anterior pituitary function and central diabetes insipidus. Magnetic resonance imaging showed thickening of the pituitary stalk and enlargement of the neurohypophysis without high intensity of the posterior lobe on T1-weighted images, which were compatible with lymphocytic infundibuloneurohypophysitis. Transsphenoidal biopsy was done and histological examination disclosed moderate fibrosis and lymphocytic infiltration not only in the posterior pituitary, but also in the adjacent anterior pituitary part of the gland. The lymphocytes both in the anterior and posterior pituitary were mainly T cells that were positive for UCHL 1, CD 3, and CD 8. Immunofluorescence of frozen tissue detected immunecomplex deposition in small vessels and the interstitium. These findings suggested that allergic reactions may play an important role in the pathogenesis of lymphocytic infundibuloneurohypophysitis.

CD3 Complex↗
PubMed1999

Double pituitary adenomas: six surgical cases.

While double pituitary adenomas have been found in approximately 1% of autopsy pituitaries, those in surgically resected material have been only rarely reported. We report herein 6 cases of double pituitary adenomas, which consisted of two histologically and/or immunohistochemically different areas among approximately 450 surgical specimens. Five out of 6 patients were men and the age was ranged between 18 and 61 years old. All these 6 patients presented acromegaly or acrogigantism and hyperprolactinemia was noted in 3 patients. In 2 patients (cases 1 and 2) the two adenomas belonged to different adenoma groups (GH-PRL-TSH group and FSH/LH group), while in the remaining 4 patients (cases 3-6) the two adenomas belonged to the same group (GH-PRL-TSH group). Thus, in all patients at least one of the two adenomas was GH-producing adenoma. Reasons for a high incidence of GH-producing adenomas in surgically resected double pituitary adenomas may include the presence of a variety of histologic subtypes among GH-producing adenomas and the advantage of cytokeratin immunostaining to distinguish these subtypes. In regard to pathogenesis of double pituitary adenomas, adenomas in cases 1 and 2 may be of multicentric occurrence, while those in cases 3-6 may occur through different clonal proliferation within originally one adenoma, resulting in diverse phenotypic expressions. Since there were patients with familial MEN 1 (case 2) and familial pituitary adenoma unrelated MEN 1 (case 3), genetic background should be also considered. Double pituitary adenomas in surgically resected material may not be so infrequent. Further molecular analysis will provide new insights into understanding the pathogenesis of pituitary adenomas and their mechanisms of multidirectional phenotypic diffrentiation.

Acromegaly↗
PubMed1999

A synthetic selective inhibitor of factor Xa, DX-9065a, reduces monocyte chemoattractant protein-1 expression after ischemia-reperfusion injury in rat liver.

Activated factor X (FXa) is a trypsinlike serine protease involved in the cascade of blood coagulation. The monocyte chemoattractant protein-1 (MCP-1) may be important in the pathophysiology of liver ischemia-reperfusion injury. We investigated the effects of a selective FXa inhibitor, DX-9065a, on MCP-1 expression after ischemia-reperfusion in the rat liver. Liver ischemia was induced in rats by occluding the portal vein for 30 min. DX-9065a was injected intravenously 5 min before vascular clamping. Serum concentrations of MCP-1 were measured by enzyme-linked immunosorbent assay. The levels of MCP-1 mRNA in the liver after reperfusion were determined by northern blot analysis. In vitro MCP-1 production by peritoneal macrophages in response to alpha-thrombin was examined. Serum concentrations of MCP-1 increased and peaked at 6 hr after reperfusion. However, pretreatment of animals with DX-9065a resulted in significantly smaller increases in the serum concentration of MCP-1 after reperfusion in a dose-dependent manner. Pretreatment with DX-9065a significantly reduced MCP-1 mRNA levels in the liver after ischemia-reperfusion. In vitro MCP-1 production by peritoneal macrophages was enhanced by alpha-thrombin. In addition, DX-9065a significantly reduced tissue factor mRNA levels in peripheral monocytes after ischemia-reperfusion, compared to untreated animals. In conclusion, a selective inhibitor of FXa, DX-9065a, limited MCP-1 production after ischemia-reperfusion of the rat liver.

Animals↗
PubMed1999

Bioavailability of dried asakusanori (porphyra tenera) as a source of Cobalamin (Vitamin B12).

We have already reported that raw nori (Porphyra tenera) contains cobalamin (Cbl) but not Cbl analogues (J. Nutr. Sci. Vitaminol., 42, 497, 1996). It seems, therefore, that it is an excellent natural vegetable source of Cbl. On the other hand, it has been reported that the Cbl nutritional status of vegetarian children deteriorated as estimated by the hematological index, mean corpuscular volume (MCV), after they had dried nori as a source of Cbl. Such a discrepancy between raw and dried nori as a source of Cbl led us to investigate whether Cbl in dried nori had different properties from that in raw nori. We found that contents of Cbl homologues determined by a bioassay method in both raw and dried nori were similar. The urinary methylmalonic acid excretion increased when human female volunteers were given 40 g of dried nori daily during the test period. On the other hand, the urinary methylmalonic acid excretion did not change when volunteers were daily given 320 g of raw nori, which was equivalent to 40 g of the dried one on the basis of dehydrated weight, during the test period. By paper chromatography, 65% of the Cbl homologues were found to be comprised of Cbl analogues in dried nori, while 73% of the Cbl homologues in the raw nori were genuine Cbl. These results were confirmed by the finding that the bioassay method gave higher values for Cbl homologues than those obtained by a competitive binding assay method using an intrinsic factor as a Cbl-binding protein. Our present data demonstrated that Cbl in raw nori can be changed into harmful Cbl analogues by the drying process.

Adult↗
PubMed1999

Obstructive sleep apnoea in a puerperal patient with Hallermann-Streiff syndrome.

A 26 yr old puerperal female with Hallermann-Streiff syndrome developed serious obstructive sleep apnoea syndrome during pregnancy. She underwent an elective Caesarean section delivery, but ending the pregnancy did not improve her clinical symptoms. By treating her with nasal continuous positive airway pressure, a worsening of her headaches and glaucoma was prevented. The administration of acetazolamide controlled all of her symptoms. Treatment with nasal ventilation is the best initial approach. It is also important to assure normal oxygenation before pregnancy since the foetus may suffer from the severe deprivation that may occur in these patients.

Acetazolamide↗
PubMed1999

Predicting the severity of graft-versus-host disease from interleukin-10 levels after bone marrow transplantation.

Acute graft-versus-host disease (GVHD) is the most important complication of allogeneic bone marrow transplantation. We investigated the possibility of predicting severe acute GVHD using plasma interleukin-10 levels in 31 patients who underwent allogeneic bone marrow transplantation. In patients with acute GVHD, the interleukin-10 (IL-10) level increased significantly from the aplastic phase through the leukocyte recovery phase after transplantation (P < 0.05, paired t-test). The ratio of the IL-10 level in the aplastic phase to that in the leukocyte recovery phase was significantly correlated with the severity of acute GVHD (P < 0. 05, t-test), and the incidence of grade III or IV disease was significantly increased (P < 0.0001). Since IL-10 antagonizes various other cytokines that induce acute GVHD, determination of the IL-10 level is equivalent to assessing the total production of cytokines promoting GVHD. The ratio of the IL-10 level in the aplastic phase to that in the recovery phase seems to be useful for predicting the subsequent risk of acute GVHD.

Acute Disease↗
PubMed1999

Intracranial cavity volume can be accurately estimated from the weights of intracranial contents: confirmation by the dental plaster casting method.

Intracranial cavity volume is used to evaluate brain size relative to the intracranial space. This volume can theoretically be obtained from the weights and densities of the brain and surrounding cerebrospinal fluid (weight method). However, the accuracy of this method has not been examined. In this study, we examined the reliability of the weight method, by comparing the intracranial cavity volumes of 41 post-mortem cases obtained by the weight method (ICVw) with those obtained by a dental plaster casting method (ICVcast) which was shown to be unbiased. The ICVw was not significantly different from the ICV cast (P=0.49, paired t-test), and the standard error of difference was 18 ml (1.3% of ICVcast). These results show that the weight method is reliable, and applicable to routine autopsies.

Aged↗
PubMed1999

Substrate specificity studies of Flavobacterium chondroitinase C and heparitinases towards the glycosaminoglycan--protein linkage region. Use of a sensitive analytical method developed by chromophore-labeling of linkage glycoserines using dimethylaminoazobenzenesulfonyl chloride.

Bacterial chondroitinases and heparitinases are potentially useful tools for structural studies of chondroitin sulfate and heparin/heparan sulfate. Substrate specificities of Flavobacterium chondroitinase C, as well as heparitinases I and II, towards the glycosaminoglycan-protein linkage region -HexA-HexNAc-GlcA-Gal-Gal-Xyl-Ser (where HexA represents glucuronic acid or iduronic acid and HexNAc represents N-acetylgalactosamine or N-acetylglucosamine) were investigated using various structurally defined oligosaccharides or oligosaccharide-serines derived from the linkage region. In the case of oligosaccharide-serines, they were labeled with a chromophore dimethylaminoazobenzenesulfonyl chloride (DABS-Cl), which stably reacted with the amino group of the serine residue and rendered high absorbance for microanalysis. Chondroitinase C cleaved the GalNAc bond of the pentasaccharides or hexasaccharides derived from the linkage region of chondroitin sulfate chains and tolerated sulfation of the C-4 or C-6 of the GalNAc residue and C-6 of the Gal residues, as well as 2-O-phosphorylation of the Xyl residue. In contrast, it did not act on the GalNAc-GlcA linkage when attached to a 4-O-sulfated Gal residue. Heparitinase I cleaved the innermost glucosaminidic bond of the linkage region oligosaccharide-serines of heparin/heparan sulfate irrespective of substitution by uronic acid, whereas heparitinase II acted only on the glucosaminidic linkages of the repeating disaccharide region, but not on the innermost glucosaminidic linkage. These defined specificities of chondroitinase C, as well as heparitinases I and II, will be useful for preparation and structural analysis of the linkage oligosaccharides.

Bacterial Proteins↗
PubMed1999

Multicenter study on the effects of day care therapy on schizophrenia: a comparison of day care patients with outpatients.

The effects of day care therapy for a period of 6 months upon patients with schizophrenia were studied through comparison with schizophrenia outpatients at four facilities in Japan. The clinical features of the 31 day care patients and 30 outpatients were evaluated by the hospital staff using the Positive and Negative Syndrome Scale (PANSS) and Global Assessment Scale (GAS), and by the patients' close relatives using the Katz Adjustment Scale (KAS) before and after 6 months of treatment. Day care patients showed a significant decrease in the general pathological score of PANSS and GAS, but outpatients did not show any comparable improvement. As for KAS scores, similar improvement was observed for both the day care patients and outpatients After 6 months, 43% of the day care patients improved on the post-/pre- PANSS total scores ratio, as against only 13% of the outpatients. In addition, 13% of the outpatients were readmitted due to an exacerbation of their symptoms, whereas all day care patients were able to remain at home for 6 months. This study clearly demonstrated that day care therapy for patients with schizophrenia was more effective than the usual outpatients treatment setting. Further therapeutic efforts (e.g. psycho-education) in day care therapy are needed in order to improve family member's evaluation of the patient.

Adult↗
PubMed1999

Scanning electron microscopy of arteriovenous malformations.

Although arteriovenous malformations (AVMs) have been known to have direct communications between arteries and veins without interposing capillaries, the exact location of arterial and venous junctions have not been defined. Utilizing microscopic and endoscopic observations, Yamada and associates identified shunting arterioles (50 mu-250 mu) directly connected to the AVM core vessels. While dissecting the AVMs in functional areas of the brain, shunting arterioles were sectioned to interrupt the arterial blood supply. This technique allowed cleavage formation between the core vessels and surrounding brain, thus avoiding brain tissue removal and preserving microcirculation to functionally critical brain. We demonstrate histologically for the first time by scanning electron microscopy shunting arterioles and communicating venules (20 mu-200 mu).

Arterioles↗