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Biomedical subjects

Y Naito

Publications and source records attributed to Y Naito.

At least 19 recordsLinked to original sources
PubMed1992

Simultaneous assay of adenosine deaminase and purine nucleoside phosphorylase activity as possible biochemical means to detect non-Hodgkin lymphomas of the oral cavity.

BACKGROUND AND METHODS: This study proposes the usefulness of simultaneous assay of adenosine deaminase (enzyme code [EC] 3.5.4.4; ADA) and purine nucleoside phosphorylase (EC 2.4.2.1; PNP) activities in a biopsy specimen as a biochemical test adjunctive to the histologic diagnosis of oral non-Hodgkin lymphomas (NHL). RESULTS: NHL tissues showed an ADA activity of more than 1428 nmol/h/mg of protein, and more than 3451 nmol/h/mg of protein was the sum of ADA and PNP activity. In contrast to this finding, all the 106 lesional tissues affected by various carcinomas, various benign tumors, various cysts, ameloblastomas, osteosarcomas, gingival hyperplasia, and inflammation showed an ADA activity of less than 1000 nmol/h/mg of protein, except for 2. The sum of ADA and PNP activity was less than 2249 nmol/h/mg of protein in these diseases, except for squamous carcinoma. Different control tissues of the oral cavity showed less than 766 nmol/h/mg of protein in ADA activity, and the highest sum of ADA and PNP activity in these was only 1384 nmol/h/mg of protein. CONCLUSIONS: These findings suggest that a strong suspicion of oral NHL is justified when the sum of ADA and PNP activity in a biopsy specimen exceeds 3000 nmol/h/mg of protein and ADA activity is greater than 1000 nmol/h/mg of protein.

Adenosine Deaminase↗
PubMed1992

Immunoreactive corticotropin-releasing hormone levels in the hypothalamus of female Wistar fatty rats.

We have studied immunoreactive corticotropin-releasing hormone (CRH) levels in the hypothalamus of female Wistar fatty rats, a strain with the fa gene transferred from the Zucker rat to the Wistar Kyoto rat, in an attempt to understand the role of CRH in the development of obesity. A study was conducted with 5-week- and 12-week-old female Wistar fatty rats and lean littermates. There was no significant difference in hypothalamic CRH levels between lean and obese rats at the age of 5 weeks (1887 +/- 99.6 vs. 1767 +/- 124 pg/tissue; mean +/- S.E.M.). Hypothalamic CRH immunoreactivities, however, were significantly lower in 12-week-old obese rats (2361 +/- 132 pg/tissue) than those in lean littermates (2992 +/- 118 pg/tissue; P less than 0.05). The difference of CRH contents between the lean and obese group becomes apparent as they grow up and develop obesity.

Aging↗
PubMed1992

Effects of a platelet-activating factor antagonist, CV-6209, on gastric mucosal lesions induced by ischemia-reperfusion.

Recent research was shown that oxygen-derived free radicals are involved in the pathogenesis of various diseases, including ischemia-reperfusion injury. We have also reported that oxygen-derived free radicals and lipid peroxidation may play an important role in gastric mucosal injury induced by ischemia-reperfusion. The hypoxanthine-xanthine oxidase system and neutrophils are considered important sources of oxygen-derived free radicals in this process. In recent years, it also has been shown that serum platelet-activating factor (PAF) levels increased during ischemia-reperfusion, and that induction of superoxide generation by neutrophils is one of the important biological effects of PAF. In the present study, we examined the effect of CV-6209, a specific PAF receptor antagonist, on gastric mucosal injury induced by ischemia-reperfusion, to shed some light on the possible involvement of PAF in such lesions. CV-6209 significantly attenuated the gastric mucosal injury induced by ischemia-reperfusion, and inhibited both an increase of thiobarbituric acid reactive substances and a decrease of alpha-tocopherol in gastric mucosa after ischemia-reperfusion. However, CV-6209 had no effect on gastric mucosal blood flow during ischemia-reperfusion. These results suggest that endogenous PAF may play an important role in gastric mucosal injury induced by ischemia-reperfusion, and that CV-6209 exerts its beneficial effect mainly by inhibiting neutrophil superoxide production induced by PAF.

Animals↗
PubMed1992

Activation of lymphokine genes in T cells: role of cis-acting DNA elements that respond to T cell activation signals.

Activation of T cells is initiated by the recognition of antigen on antigen presenting cells to exert the effector functions in immune and inflammatory responses. Two types of helper T cell (Th) clones (Th1 and Th2) are defined on the basis of different patterns of cytokine (lymphokine) secretion. They determine the outcome of an antigenic response toward humoral or cell-mediated immunity. Although lymphokine genes are coordinately regulated upon antigen stimulation, they are regulated by the mechanisms common to all as well as those which are unique to each gene. For most lymphokine genes, a combination of phorbol esters (phorbol 12-myristate 13 acetate, PMA) and calcium ionophores (A23187) is required for their maximal induction. Yet phorbol ester alone or calcium ionophore alone produce several lymphokines. The production of the granulocyte-macrophage colony stimulating factor (GM-CSF) is completely dependent on the two signals. We have previously found a cis-acting region spanning the GM-CSF promoter region (positions -95 to +27) that confers inducibility to reporter genes in transient transfection assays. Further analysis identified three elements required for efficient induction, referred to as GM2, GC-box and conserved lymphokine element (CLE0). GM2 defines a binding site for protein(s) whose binding is inducible by PMA. One protein, NF-GM2 is similar to the transcription factor NF-kB. GC-box is a binding site for constitutively bound proteins. CLEO defines a binding site for protein(s) whose optimum binding is stimulated by PMA and A23187. Viral trans-activators such as Tax (human T cell leukemia virus-1, HTLV-1) and E2 (bovine papilloma virus, BPV) proteins are other agents which activate lymphokine gene expression by bypassing T cell receptor (TCR) mediated signaling. The trans-activation domain of E2 and Tax is interchangeable although they have no obvious sequence homology between them. The viral trans-activators appear to target specific DNA binding protein such as NF-kB and Sp1 to cis-acting DNA site and promote lymphokine gene expression without TCR-mediated stimulation.

Animals↗
PubMed1992

Augmentative effects of tumor necrosis factor-alpha (human, natural type) on polymorphonuclear leukocyte-derived superoxide generation induced by various stimulants.

We investigated the effects of tumor necrosis factor-alpha (human, natural type: n-TNF) on polymorphonuclear leukocyte (PMN)-derived superoxide generation by the new method of Cypridina luciferin analog-dependent chemiluminescence, which had high sensitivity and specificity to superoxide. Preincubation of PMNs with n-TNF for 3 min increased PMN-derived superoxide generation induced by phorbol myristate acetate, A23187, opsonized zymosan and N-formyl-methionyl-leucyl-phenylalanine in a concentration dependent manner (0.5-50 Japan reference units/ml of n-TNF). In addition, the enhanced PMN-derived superoxide generation by n-TNF showed a positive correlation to the preincubation time of PMNs with n-TNF (3-15 min). However, a direct incubation of PMNs with n-TNF for 1 h did not induce superoxide from PMNs without the above stimulants. The augmentative effects of n-TNF on PMN-derived superoxide generation should be useful in the PMN-mediated host defense mechanism, such as bactericidal and antitumor activity. The local concentration of n-TNF and the n-TNF-PMN contact time are considered very important in obtaining these effects more efficiently in addition to the presence of PMN-stimulants including complements, chemotactic peptides and phorbol esters.

Dose-Response Relationship, Drug↗
PubMed1992

Induction of cystatin S in rat submandibular glands by papain.

1. Papain (a cysteine proteinase) were administered into the oral cavity of rats twice daily for 5 days. This treatment caused a dramatic increase in the level of cystatin S (a cysteine proteinase inhibitor belonging to family 2 of cystatin superfamily) in enlarged submandibular glands. 2. Immunochemical analysis using antibody against rat cystatin S and electrophoretic analysis confirmed that the protein induced by papain was identical to that induced by isoproterenol. 3. Induction of the cystatin S in the submandibular glands by oral administration of papain suggested a biological response which plays a role in preventing injury exogenous proteinase.

Animals↗
PubMed1992

Responses of plasma adrenocorticotropic hormone, cortisol, and cytokines during and after upper abdominal surgery.

There is currently accumulating evidence for bidirectional communication between the neuroendocrine and immune systems. Various cytokines have been suggested to be involved in the stimulation of stress hormone secretion during the times of infection and inflammation. To assess the possible involvement and pathophysiologic significance of cytokines in the mechanisms responsible for the perioperative stress response of the hypothalamo-pituitary-adrenal axis, we observed the changes of plasma adrenocorticotropic hormone and cortisol levels together with those of plasma endotoxin and cytokine levels. In patients undergoing pancreatoduodenectomy, perioperative stimulation of adrenocorticotropic hormone and cortisol secretion was accompanied by a significant elevation of plasma cytokine levels. Application of epidural block up to the upper thoracic levels failed to suppress this stress response effectively. In patients undergoing unilateral total hip replacement, the response of plasma hormone levels was smaller and briefer with no significant increase of plasma cytokine levels. Application of epidural block up to the lower thoracic levels suppressed this hormonal response almost completely. In patients undergoing pancreatoduodenectomy, a significant elevation of plasma endotoxin level was followed by a gradual but significant elevation of plasma tumor necrosis factor alpha and interleukin-6 levels. It seems likely that the stimulatory effects of these cytokines on the secretion of adrenocorticotropic hormone and cortisol might be involved in the development of the greater and more prolonged stress response of hypothalamo-pituitary-adrenal axis. Our present study suggests that not only neural input from the surgical wound but also stimulation of cytokine production were responsible for the development of the stress response of the hypothalamo-pituitary-adrenal axis during and after upper abdominal surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1992

Role of leukotrienes in gastric mucosal injury induced by ischemia-reperfusion in rats.

This study was designed to clarify the role of leukotrienes (LTs) in gastric injury induced by ischemia-reperfusion in rats. Gastric lesions were produced by clamping of the celiac artery and by reoxygenation following clamping. Administration of AA-861, a lipoxygenase inhibitor, significantly inhibited the increase in the total area of the gastric erosions and the increase in thiobarbituric acid-reactive substances in the gastric mucosa. Administration of YM-638, a peptide LT antagonist, showed protective effects similar to AA-861. These results suggest that the protective effects of AA-861 and YM-638 against ischemia-reperfusion-induced gastric injury were due to their antioxidative action.

Animals↗
PubMed1992

Changes in superoxide dismutase activity in the gastric mucosa of peptic ulcer patients.

A highly sensitive chemiluminescence method for determining superoxide dismutase (SOD) activities in human gastric mucosa obtained by endoscopic biopsy is described. As the chemiluminescence probe, we used Cypridina luciferin analogue (CLA), a very sensitive and specific probe to detect superoxide generated from hypoxanthine-xanthine oxidase system. SOD activity in the gastric mucosa was assayed by the inhibition of CLA-dependent chemiluminescence in highly diluted tissue homogenates. SOD activity was distributed throughout the gastric mucosa. The marginal mucosa of peptic ulcers showed significantly lower SOD activity when the ulcer was in the active stage, and during the healing stage showed high activity when compared to the endoscopically normal adjacent mucosa of the same patients. The preliminary data suggest that enzymatic SOD in the gastric mucosa may play an important role in the pathogenic and healing processes of human peptic ulcers.

Adult↗
PubMed1992

The effects of interferon-beta on phorbol ester or calcium ionophore-induced intercellular adhesion molecule-I expression in epidermal carcinoma cells.

Keratinocyte intercellular adhesion molecule (ICAM)-I expression is induced by interferon (IFN)-gamma. It has been previously reported that IFN-beta suppresses IFN-gamma-induced ICAM-I expression in A431 cells, a human squamous cell carcinoma cell line. In this study, the suppression mechanisms were investigated at the post second messenger level. Both 12-O-tetradecanoylphorbol-13-acetate (TPA) and calcium ionophore (A23187) induce ICAM-I expression in A431 cells. ICAM-I expression induced by either was not suppressed with cotreatment with IFN-beta. Furthermore, IFN-beta did not inhibit the translocation of protein kinase C (PKC) by TPA. It appears that the pathways involved in ICAM-I expression induced by activation of PKC or increased in intracellular Ca++ are not affected by IFN-beta.

Calcimycin↗
PubMed1992

A sensitive enzymatic method (SK-013) for detection and quantification of specific periodontopathogens.

Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola have been found to predominate in periodontal pockets of patients with adult periodontitis. These microorganisms hydrolyze the synthetic peptide N-benzoyl-DL-arginine-2-naphthylamide (BANA). In this study, we developed an enzymatic method, designated SK-013, to detect the existence of these microorganisms in subgingival plaque bacteria. This enzymatic method was based on the observation of the hydrolysis of N-carbobenzoxy-glycyl-glycyl-arginyl-3,5-dibromo-4-hydroxyaniline (N-CBz-Gly-Gly-Arg-DBHA) and made more sensitive by adding an enhancing system. The SK-013 was specifically positive for P. gingivalis, B. forsythus, T. denticola, and some strains of Capnocytophaga species, but was not specific for any of the other bacterial strains tested. This SK-013 system may be valuable for detection and quantification of periodontal disease-associated bacteria in subgingival plaque and thus for diagnosis of periodontal infections.

Bacteroides↗
PubMed1992

A sensitive enzymatic method (SK-013) for detection of Treponema denticola, Porphyromonas gingivals and Bacteroides forsythus in subgingival plaque samples.

An enzymatic method, SK-013, was developed for rapid detection of the peptidase activity in subgingival plaque samples. This method was found to have specificity for Porphyromonas gingivalis, Treponema denticola, Bacteroides forsythus, and some Capnocytophaga strains. The purpose of this study was to determine whether SK-013 could indicate the presence of periodontopathic bacteria, including T. denticola, P. gingivalis and B. forsythus, which produce trypsin-like enzymes. Subgingival plaque samples were taken from 10 clinically healthy sites and 30 periodontally diseased sites with 3 paper points. SK-013 activity of plaque samples was assayed, and the numbers of T. denticola, P. gingivalis and B. forsythus in the sample were counted by immunofluorescence technique. In diseased sites, the SK-013 activity was significantly correlated with clinical parameters such as Gingival Index, Plaque Index, probing depth and bleeding on probing. A significant correlation was found between the presence of these organisms and SK-013 activity. Correlation coefficients between the presence of T. denticola and SK-013 activity were higher than those with other organisms. These findings indicate that the SK-013 is useful as an indicator of cell population of T. denticola, P. gingivalis and B. forsythus in subgingival plaque.

Bacteroides↗
PubMed1992

Roles of interleukin-1 alpha and -1 beta in endotoxin-induced suppression of plasma gonadotropin levels in rats.

Using specific antagonists to rat interleukin (IL)-1 alpha and IL-1 beta, the roles of these IL-1s in endotoxin-induced suppression of plasma gonadotropin levels in freely-moving rats were studied. In orchiectomized rats, recombinant rat IL-1 alpha and IL-1 beta administered into the lateral ventricles almost equipotently suppressed plasma LH levels. Twenty five micrograms of bacterial endotoxin or lipopolysaccharide (LPS) administered similarly showed a comparable effect as that of 1 microgram IL-1 alpha or IL-1 beta, and completely lowered plasma LH levels by 60 min after the injection. To examine the roles of endogenous IL-1 alpha and IL-1 beta, anti-rat IL-1 alpha antiserum (anti-IL-1 alpha) and a recombinant human IL-1 receptor antagonist (IL-1ra) were used as specific blockers for IL-1 alpha and IL-1 beta, respectively. Anti-IL-1 alpha (10 microliters) or IL-1ra (10 micrograms) administered intracerebroventricularly (icv) with 25 micrograms LPS, significantly attenuated the LPS-induced effect on plasma LH levels during the first 60 min after LPS infusion, but not during the second 60 min. LPS at a dose of 5 micrograms induced smaller but still significant changes in plasma LH levels compared with 25 micrograms LPS or 1 microgram IL-1 beta. IL-1ra (10 micrograms) completely blocked LH suppression induced by 1 microgram IL-1 beta, but did not completely reverse the changes of LH induced by 5 micrograms LPS. IL-1ra injected iv also significantly attenuated the early suppressive effect of iv administered LPS, but not its late effect on plasma LH levels. However, iv administered IL-1ra had no influence on the effects of icv administered LPS. These data indicate that at least a part of plasma LH suppression caused by icv administered LPS is mediated via IL-1 alpha and IL-1 beta synthesized within the brain, while factor(s) other than IL-1 also participate in the LPS-induced change, particularly during the later period. A similar mechanism may also work peripherally in the case of iv administered LPS-induced plasma LH suppression.

Animals↗
PubMed1992

Effects of repetitive administration of recombinant human interleukin-1 beta, an analog or corticotropin-releasing hormone combined with lysine vasopressin on rats with glucocorticoid-induced secondary adrenocortical insufficiency.

We investigated effects of corticotropin-releasing hormone (CRH), lysine vasopressin and interleukin (IL)-1 beta[1-148], a less pyrogenic analog of human IL-1 beta, on the hypothalamo-pituitary-adrenal axis in a rat model of secondary adrenocortical insufficiency. After 2 weeks of corticosterone 21-sodium succinate treatment, hypothalamic CRH, anterior pituitary adrenocorticotropic hormone (ACTH) and the adrenal weight of the rats decreased significantly and their plasma ACTH showed a significantly smaller response to ether stress, as did plasma corticosterone level. A mixed solution of CRH (10 micrograms) and lysine vasopressin (2 micrograms) or recombinant human IL-1 beta[1-148] (1 micrograms), administered to these rats for 7 days, apparently accelerated the recovery of the pituitary and adrenocortical responsiveness to ether stress and significantly increased the recovery rate of anterior pituitary ACTH contents and adrenal weight. The IL-1 beta analog also increased hypothalamic CRH. These data indicated that, in a rat model with glucocorticoid-induced adrenocortical insufficiency, synthesis and release of hypothalamic CRH, pituitary ACTH and adrenal glucocorticoid were all considerably affected. CRH combined with lysine vasopressin or a less pyrogenic IL-1 beta analog, when administered to these rats, accelerated the recovery of the pituitary and the adrenocortical functions significantly, suggesting the potential clinical usefulness of these peptides.

Adrenal Insufficiency↗
PubMed1992

The relationship between polysaccharide antigen and interleukin-1 beta producing activity in Porphyromonas gingivalis.

Strains of Porphyromonas gingivalis were serologically classified into three groups (a, b, and c) by immunodiffusion test using the autoclave extracted antigens. All tested strains had proteolytic activity, but the activity differed from strain to strain, regardless of serogroup. It was found that serogroup a strains had more collagenolytic activity than did serogroup b (p < 0.05), but that the three groups have no remarkable differences in trypsin activity. All autoclave extracted serogroup-specific antigens induced the release of interleukin-1 beta (IL-1 beta) from human peripheral monocytes. Serogroup-specific antigen of an invasive strain designated 16-1 (serogroup b) induced the highest release of IL-1 beta among all samples. The results of immunoblotting tests and IL-1 beta production indicated that there are serogroup-specific polysaccharide other than lipopolysaccharide in P. gingivalis.

Antigens, Bacterial↗