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Biomedical subjects

T Miwa

Publications and source records attributed to T Miwa.

At least 91 records · Page 5Linked to original sources
PubMed1999

The therapeutic effect of bovine lactoferrin in the host infected with Helicobacter pylori.

BACKGROUND: It remains unclarified whether bovine lactoferrin (bLF) can exert a therapeutic effect on the host infected with Helicobacter pylori. METHODS: Germfree BALB/c mice were orally inoculated with H. pylori to induce infection. Three weeks after infection the mice were given bLF orally once daily for 2 or 4 weeks and were then killed to examine the bacterial number in the stomach and the serum antibody titer to H. pylori. To count the number of epithelium-bound H. pylori, the resected stomach was agitated in phosphate-buffered saline to remove non-bound H. pylori before bacterial enumeration. RESULTS: The administration of 10 mg bLF for 3 to 4 weeks decreased the number of H. pylori in the stomach to one-tenth and also exerted a significant inhibitory effect on the attachment of H. pylori to the stomach. As a result, the serum antibody titer to H. pylori, whose level is presumed to represent the size of the immune response by the host, thereby reflecting the degree of bacterial attack, decreased to an undetectable level. CONCLUSIONS: These findings suggest that bLF exerts an inhibitory effect on colonizing H. pylori by detaching the bacterium from the gastric epithelium and by exerting a direct anti-bacterial effect.

Animals↗
PubMed1999

Synthesis of S-adenosyl-L-homocysteine hydrolase inhibitors and their biological activities.

Several nucleosides have been prepared as a possible inhibitor of human S-adenosyl-L-homocysteine (SAH) hydrolase for the development of anti-viral agents. Recently, SAH hydrolase has been considered as an attractive target for parasite chemotherapy for malaria. We report synthesis of several nucleosides including carbocyclic nucleosides and their inhibitory activities against recombinant malaria and human SAH hydrolases.

Adenine↗
PubMed1999

Characterization of novel cysteine proteases from germinating cotyledons of soybean [Glycine max (L.) Merrill].

The enzymatic properties of novel cysteine proteases D3-alpha and beta which were purified from germinating soybean cotyledons were investigated. The enzyme activities were exhibited in the presence of a thiol reagent, such as 2-mercaptoethanol, and apparently inhibited by E-64, a cysteine protease inhibitor. Hydrolytic activities toward carbobenzoxy-Phe-Arg-MCA were detected at a pH above 4.0. The optimum temperature for activities was about 40 degrees C. The isoelectric point of D3-alpha and beta was 4.4 and 4. 7, respectively. The molecular mass of D3-alpha and beta, measured by MALDI/TOF mass spectrometry, was 26,178 and 26,429 Da, respectively. The substrate specificities of the enzymes were examined using peptide-MCAs and peptides, and cathepsin L-like broad specificity was observed at pH 4.0. These results demonstrated that these enzymes are cysteine endopeptidases [EC 3.4.22.-] like papain [EC 3.4.22.2].

Amino Acid Sequence↗
PubMed1999

Characterization of mouse DAF on transfectant cells using monoclonal antibodies which recognize different epitopes.

Several membrane proteins prevent host cells from homologous complement attack. In humans, one such protein, decay-accelerating factor (DAF), exists as two isoforms, a GPI anchored form and a secreted form, which are generated by alternative splicing. DAF in mouse is also expressed as two isoforms, a GPI anchored form (GPI-DAF) and a transmembrane form (TM-DAF), which are produced from two separate genes. In this study, we transfected cDNA of mouse GPI-DAF or TM-DAF into Chinese hamster ovary (CHO) cells. Both isoforms of DAF on CHO cells were shown to regulate mouse complement C3 deposition mediated by the classical and alternative pathways and the inhibitory activity of both isoforms was species restricted. The two mouse DAF isoforms were effective against rat complement but not against human and guinea pig complement. Furthermore, we produced hamster mAbs to mouse DAF using GPI-DAF transfectant cells and established seven unique mAbs (RIKO-1-7). Western blotting analysis using RIKO-3, which reacts with both GPI-DAF and TM-DAF, and RIKO-4, which is an anti-GPI-DAF specific mAb, indicated that GPI-DAF was expressed on erythrocytes, spleen and testis, and that TM-DAF was expressed only in testis.

Animals↗
PubMed1999

mRNA expression of complement components and regulators in rat arterial smooth muscle cells.

The presence of C5b-9 complexes, some complement regulators, and abundant cytokines in atherosclerotic lesions has been reported. However, it is unclear whether these complement-associated proteins are produced by vascular smooth muscle cells (SMCs) and how they are influenced by the cytokines. In the present study, we demonstrated, by the reverse transcription-polymerase chain reaction method, the mRNA expression of complement components (C3, C4, and C5) and membrane regulators (decay-accelerating factor, membrane cofactor protein, Crry, and CD59) in cultured SMCs derived from the rat carotid artery. The expression of C9 mRNA was also induced upon stimulation by interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and/or lipopolysaccharide (LPS). Northern blot analysis showed that the mRNA expression of C3, C4, DAF and Crry was up-regulated, but that of CD59 was down-regulated by IFN-gamma, TNF-alpha and/or LPS alone or by synergy. The increase of C3 mRNA by TNF-alpha or LPS and that of C4 mRNA by IFN-gamma was induced in a dose-dependent manner. The results indicate that the arterial SMCs of rat have the ability to produce complement components and regulators, which is affected by cytokines and/or LPS. Since atherosclerosis is characterized by the intimal proliferation of SMCs, the complement system including its regulators may be involved in the pathogenesis of the disease.

Animals↗
PubMed1999

Role of apoptosis induced by Helicobacter pylori infection in the development of duodenal ulcer.

BACKGROUND: Helicobacter pylori affects gastric epithelium integrity by acceleration of apoptosis. However, it remains unclear what product of the bacteria causes apoptosis, or whether or not the apoptosis is involved in the development of ulcers. AIMS: To elucidate the factor from H pylori that causes acceleration of apoptosis and the role of apoptosis in the development of duodenal ulcer in H pylori infection. PATIENTS: Five H pylori negative healthy volunteers, 47 H pylori positive patients with duodenal ulcer, and 35 H pylori positive patients with gastric ulcer. METHODS: An endoscopic examination was carried out to diagnose ulcers and determine their clinical stage. To analyse apoptosis, a cell cycle analysis was performed using biopsy specimens. RESULTS: There was a significant correlation between the urease activity of the H pylori strain and the level of apoptosis induced by this bacterial strain. Moreover, in duodenal ulcer patients infected with H pylori, the patients with an active ulcer exhibited a significantly higher level of apoptosis than those with ulcers at both the healing and scarring stages. CONCLUSION: These findings suggest that acceleration of apoptosis in the antral mucosa caused by the urease of H pylori plays a crucial role in the development of ulcers in the duodenum.

Adolescent↗
PubMed1999

Angiotensin II type 2 receptor overexpression activates the vascular kinin system and causes vasodilation.

Angiotensin II (Ang II) is a potent vasopressor peptide that interacts with 2 major receptor isoforms - AT1 and AT2. Although blood pressure is increased in AT2 knockout mice, the underlying mechanisms remain undefined because of the low levels of expression of AT2 in the vasculature. Here we overexpressed AT2 in vascular smooth muscle (VSM) cells in transgenic (TG) mice. Aortic AT1 was not affected by overexpression of AT2. Chronic infusion of Ang II into AT2-TG mice completely abolished the AT1-mediated pressor effect, which was blocked by inhibitors of bradykinin type 2 receptor (icatibant) and nitric oxide (NO) synthase (L-NAME). Aortic explants from TG mice showed greatly increased cGMP production and diminished Ang II-induced vascular constriction. Removal of endothelium or treatment with icatibant and L-NAME abolished these AT2-mediated effects. AT2 blocked the amiloride-sensitive Na(+)/H(+) exchanger, promoting intracellular acidosis in VSM cells and activating kininogenases. The resulting enhancement of aortic kinin formation in TG mice was not affected by removal of endothelium. Our results suggest that AT2 in aortic VSM cells stimulates the production of bradykinin, which stimulates the NO/cGMP system in a paracrine manner to promote vasodilation. Selective stimulation of AT2 in the presence of AT1 antagonists is predicted to have a beneficial clinical effect in controlling blood pressure.

Actins↗
PubMed1999

[Long-term endoscopic follow-up for peptic ulcer patients after eradication of H. pylori; comparison with the maintainance therapy by H2-blocker].

This study was aimed to clarify the endoscopic findings and the decline of serum IgG titer after successful eradication of H. pylori in long-term (from 2 to 7 years). Forty-six H. pylori-positive peptic ulcer (22 GU and 26 DU) cases were eradicated with antimicrobial therapy. Sixty-nine non-eradicated DU cases who received maintainance therapy with H2-blocker were control group. Biopsy urease test (BUT) and culturing was performed to diagnose the H. pylori infection. Anti-H. pylori IgG titer (EIA) were also measured in some cases, pre and 6, 12, 24 months after the eradication. In 3 cases, H. pylori were recrudescent and only in a case, DU recurred during 5 years after eradication. Meanwhile, in 55% of control cases, DU were recurred during same periods. In 62% of eradicated cases, serum IgG-antibody to H. pylori declined below the cut-off level during 2 years after eradication. It was certified that eradication therapy against H. pylori prevents ulcer recurrence for long time, and re-rise of serum IgG titer to H. pylori might predict a recrudescence of infection.

Adult↗
PubMed1999

Effect of exogenous tetragastrin on gastric myoelectrical activity in humans.

It is known that cutaneous electrogastrography (EGG) undergoes a change after food ingestion, showing increases in frequency and amplitude compared with preprandial values, but the factors regulating such changes remain to be elucidated. Paying special attention to gastrin, one of gastrointestinal peptides released after food ingestion, we administered tetragastrin in an exogenous manner and evaluated its effects on EGG in the present study. In healthy subjects, the intramuscular injection of tetragastrin significantly increased EGG frequency dose-dependently, but caused no significant change in amplitude. These results suggest that the increase in endogenous gastrin release is one of the mechanisms which underlies the increase in EGG frequency after food ingestion.

Adult↗
PubMed1998

Ion chromatography on anion exchangers modified with mucopolysaccharides.

Anion exchangers modified with mucopolysaccharides, such as chondroitin sulfates and heparin, were used for the stationary phase in ion chromatography. Unusual retention behavior of anions was observed for the modified stationary phases. A 50-microM concentration of tartaric acid could separate inorganic anions in a reasonable time. The retention of analytes could be changed by changing the eluent composition.

Chromatography, Ion Exchange↗
PubMed1998

Prognostic value of cyclin E and p53 expression in gastric carcinoma.

BACKGROUND: Cyclins and wild-type p53 are prime cell cycle regulators and may be involved in tumorigenesis. Cyclin E is a late G1 cyclin and its abnormalities have been reported in several cancers. The authors investigated the correlation between cyclin E expression and progression of gastric carcinoma. METHODS: The expression of cyclin E and p53 proteins was investigated retrospectively in 116 patients with gastric carcinoma. Immunohistochemical staining of the paraffin sections was performed using monoclonal antibodies to cyclin E and p53. RESULTS: The total cyclin E positive rate was 44.0% (51 of 116) of all cases, 26 of which were strongly positive. Strong cyclin E expression frequently was observed in deeply invasive tumors, tumors with lymph node metastasis, and tumors of advanced stage. The incidence of p53 expression was higher in the cyclin E positive tumors than in the other tumors. With regard to prognosis, patients whose tumors had both strong positivity for cyclin E and positivity for p53 had significantly poorer prognosis. In multivariate analysis, the combined variable of cyclin E and p53 was an independent prognostic indicator together with serosal invasion and tumor size. CONCLUSIONS: These data suggest the cyclin E expression correlates with p53 expression and may contribute to the progression of gastric carcinoma. The combined variable of cyclin E and p53 expression could be a useful prognostic indicator in patients with gastric carcinoma.

Adult↗
PubMed1998

Retrograde transport of nerve growth factor from olfactory bulb to olfactory epithelium.

NGF is produced in the olfactory bulb and transported from the bulb to cholinergic neurons in the horizontal limb of the diagonal band. Although the expression of NGF receptors has been reported in olfactory epithelial cells, no correlation between NGF and olfactory epithelial cells has been found. This study aimed to define whether or not retrograde transport of NGF occurs in the olfactory neural system using the method of radioluminography. 125I-labeled NGF injected into the olfactory bulb was taken up and transported to the olfactory epithelium 18 h after injection. This finding suggests that bulbar NGF may act as a neurotrophic factor in olfactory epithelial cells.

Animals↗
PubMed1998

Coupling between single muscle spindle afferent and EMG in human wrist extensor muscles: physiological evidence of skeletofusimotor (beta) innervation.

OBJECTIVES: This study was conducted to find physiological evidence of skeletofusimotor innervation in man. METHODS: Discharges of 38 single muscle spindle afferents from m. extensor carpi radialis were recorded from 9 subjects during steady isometric contractions of wrist extension. Correlation between these afferents and rectified surface EMG was investigated by estimating cumulant density function. RESULTS: In the cumulant density estimate between spindle afferent and EMG, a positive EMG peak was obtained prior to afferent firing between -30 and -10 ms in 15 afferents (39%). CONCLUSIONS: The present finding indicates coupling between spindle afferents and extrafusal activity and suggests the widespread skeletofusimotor innervation in human muscle spindle.

Adult↗
PubMed1998

Effects of L-carnitine supplementation on muscular symptoms in hemodialyzed patients.

Various muscle symptoms are well recognized among patients on maintenance hemodialysis. Carnitine deficiency may be an important factor of dialysis-associated muscle symptoms, whereas high-dose L-carnitine supplementation may result in unphysiologically high plasma levels of carnitine and carnitine esters. We studied the effect of low-dose L-carnitine treatment (500 mg/d) on muscle symptoms, plasma carnitine fractions, and lipid profiles in 30 periodically dialyzed patients with muscular weakness, fatigue, or cramps/aches. After 12 weeks of L-carnitine treatment, about two-thirds of patients had at least some improvement in muscular symptoms, whereas carnitine fractions were normal or slightly above normal ranges, but lipid profiles showed no demonstrable changes. This study also showed the correlation between plasma-free carnitine deficiency and months on dialysis. These results suggest that prolonged low-dose L-carnitine treatment can improve dialysis-associated muscle symptoms by restoring carnitine tissue levels and washing out acyl moieties.

Administration, Oral↗
PubMed1998

TrkA expression in mouse olfactory tract following axotomy of olfactory nerves.

The olfactory bulb is one of the brain regions that synthesizes the nerve growth factor (NGF). Functional roles of the bulbar NGF remain to be determined. The aim of the present study was, using an antibody specific to the high-affinity NGF receptor (trkA), to examine immunohistochemically the distribution of the NGF receptor in the mouse olfactory tract, under normal conditions and during regenerative processes. In normal mouse olfactory epithelia, trkA immunoreactive cell bodies were only seen in basal cells. Cell bodies of olfactory receptor cells did not express trkA immunoreactivity, but their neuronal processes (olfactory nerve fibres and bundles in the olfactory mucosa and the olfactory bulb) displayed trkA immunoreactivity. After axotomy of olfactory nerves, regenerating olfactory cells (basal cells and olfactory receptor cells) expressed trkA immunoreactivity in intramucosal and intrabulbar neuronal processes of olfactory receptor cells. These results suggest involvement of the bulbar NGF in the process of synaptogenesis and/or regeneration of the olfactory nervous system.

Animals↗