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Biomedical subjects

H Maeda

Publications and source records attributed to H Maeda.

At least 307 records · Page 17Linked to original sources
PubMed1998

Deletion of bone marrow stromal cell antigen-1 (CD157) gene impaired systemic thymus independent-2 antigen-induced IgG3 and mucosal TD antigen-elicited IgA responses.

Bone marrow stromal cell Ag-1 (BST-1; CD157)-deficient mice were generated to examine the immunologic roles of the molecule in vivo. In BST-1(-/-) mice, the development of peritoneal B-1 cells was delayed, and CD38(low/-) B-lineage cells were increased in the bone marrow and spleen. Partial impairment of thymus-independent (TI-2) and thymus-dependent (TD) Ag-specific immune responses was noted in the systemic and mucosal compartments of BST-1(-/-) mice, respectively. Although serum Ig levels as well as TD and TI-1 Ag-specific systemic immune responses were normal, the TI-2 Ag-induced IgG3 response was selectively impaired. Oral immunization of BST-1(-/-) mice with cholera toxin, a potent TD Ag for the induction of IgA response, resulted in the poor production of Ag-specific Abs at the intestinal mucosa accompanied by the reduced number of Ag-specific IgA-producing cells in the lamina propria. These results indicate that BST-1 has roles in B cell development and Ab production in vivo.

ADP-ribosyl Cyclase↗
PubMed1998

The possible effect of nitric oxide on relaxation and noradrenaline release in the isolated rabbit urethra.

We evaluated the effects of N(omega)-nitro-L-arginine (L-NNA, a nitric oxide (NO) synthase inhibitor) and carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO, a NO scavenger) on NO-mediated relaxation and noradrenaline release from adrenergic nerve endings induced by electrical field stimulation in the rabbit urethra. Electrical field stimulation caused frequency-dependent relaxation of rabbit urethral smooth muscles precontracted with phenylephrine. The relaxation responses were significantly inhibited by treatment with L-NNA or carboxy-PTIO. The inhibitory effect of carboxy-PTIO was significantly weaker than that of L-NNA. Electrical field stimulation caused significant noradrenaline release from adrenergic nerve endings in the rabbit urethra. Treatment with carboxy PTIO enhanced electrical field stimulation-induced noradrenaline release, and simultaneous application of L-NNA and carboxy-PTIO did not further enhance noradrenaline release in the rabbit urethra. As carboxy-PTIO reacts only with the free radical NO, the present results suggest that free radical NO and NO-containing compounds are involved in the L-NNA-sensitive nitrergic nerve-mediated relaxation in the rabbit urethra. At the same time free radical NO has a prejunctional action by which it may inhibit noradrenaline release from adrenergic nerves.

Animals↗
PubMed1998

The S-layer protein from Campylobacter rectus: sequence determination and function of the recombinant protein.

The gene encoding the crystalline surface layer (S-layer) protein from Campylobacter rectus, designated slp, was sequenced and the recombinant gene product was expressed in Escherichia coli. The gene consisted of 4086 nucleotides encoding a protein with 1361 amino acids. The N-terminal amino acid sequence revealed that Slp did not contain a signal sequence, but that the initial methionine residue was processed. The deduced amino acid sequence displayed some common characteristic features of S-layer proteins previously reported. A homology search showed a high similarity to the Campylobacter fetus S-layer proteins, especially in their N-terminus. The C-terminal third of Slp exhibited homology with the RTX toxins from Gram-negative bacteria via the region including the glycine-rich repeats. The Slp protein had the same N-terminal sequence as a 104-kDa cytotoxin isolated from the culture supernatants of C. rectus. However, neither native nor recombinant Slp showed cytotoxicity against HL-60 cells or human peripheral white blood cells. These data support the idea that the N-terminus acts as an anchor to the cell surface components and that the C-terminus is involved in the assembly and/or transport of the protein.

Amino Acid Sequence↗
PubMed1998

XAFS in the high-energy region.

XAFS (X-ray absorption fine-structure) spectra were measured near K-absorption edges of Ce (40.5 keV), Dy (53.8 keV), Ta (67.4 keV) and Pt (78.4 keV). The blunt K-edge jump due to the finite lifetime of the core hole was observed. This makes it difficult to extract EXAFS (extended X-ray absorption fine-structure) functions at low k values. Local structure parameters can be evaluated from the EXAFS spectra above K-absorption edges in the high-energy region as well as from those above L(III)-edges. It was found that the finite-lifetime effect of the core hole is effectively taken into the photoelectron mean-free-path term, as predicted theoretically.

Journal Article↗
PubMed1998

Dodecyldimethylamine Oxide Micelles in Solutions without Added Salt

Critical micelle concentrations (cmc) of dodecyldimethylamine oxide (DDAO) were determined at 25°C in solutions in the absence of salt at different pH values by four methods: surface tension, dye solubilization (Sudan III), pH-concentration break points, and counterion (Cl-) activity. With the aid of the cmc values, the degree of ionization of DDAO micelle alphaM was determined as a function of pH from the hydrogen ion titration. The cmc increased sharply in a narrow range of alphaM from 0.35 to 0.40. This destabilization of micelles was also noted on the anomalous change of pK on the hydrogen ion titration curve. The counterion activity was measured potentiometrically, and the degree of the counterion binding theta was determined as a function of alphaM. The value of theta showed a sharp increase with alphaM also around 0.4. The line width of NMR absorption peak of 35Cl ions was well correlated with alphaM. The surface electric potentials psi0 of DDAO micelles were evaluated from both the hydrogen ion titration and the acid-base indicators, and the former value was larger than the latter one. A procedure is proposed to compare the stabilities of the micelles having different alphaM values. The result indicates much larger dependences on alphaM than those uncorrected for different ionic strengths at the cmc. Copyright 1998 Academic Press. Copyright 1998Academic Press

Journal Article↗
PubMed1998

Modulation of enhanced vascular permeability in tumors by a bradykinin antagonist, a cyclooxygenase inhibitor, and a nitric oxide scavenger.

The mechanism of the enhanced vascular permeability and retention (EPR) effect seen in solid tumors was investigated with sarcoma 180 (S-180) in mice by using the bradykinin receptor antagonist D-Arg-[Hyp3,Thi5,D-Tic7,Oic8]bradykinin] (HOE 140), the nitric oxide (NO) scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), and the cyclooxygenase (prostaglandin synthase) inhibitor indomethacin. In the S-180 solid tumor model, administration of HOE 140 (0.65 or 1.3 microg/kg/8 h, s.c.), PTIO (167 mg/kg/2 h, four times/8 h, i.p.), or indomethacin (5 or 10 mg/kg/day, three times, i.p.) significantly suppressed the EPR effect in the tumor, and the combined administration of these agents achieved a stronger inhibition of the EPR effect than did each compound alone. Indomethacin (10 mg/kg/day, three times) plus PTIO (167 mg/kg/2 h, four times) given i.p. had the greatest inhibition (70%) on the EPR effect. When HOE 140 was administered s.c. at a dose of 13 microg/kg/12 h for 2 weeks after tumor inoculation, growth of the solid tumor was also suppressed by 32%, by tumor weight. In the ascitic form of S-180, i.p. administration of HOE 140 at 13 microg/kg/12 h initiated immediately after tumor inoculation significantly suppressed formation of S-180 tumor ascites; the life span of ascitic S-180 tumor-bearing mice was prolonged at the same dose of HOE 140. The expression of inducible NO synthase mRNA and of cyclooxygenase 2 mRNA in S-180 tumor tissue was highly elevated, as evidenced by Northern blotting and reverse transcription-PCR and by Southern blot analyses. These results indicate that bradykinin, NO, and prostaglandins play an important role in enhanced vascular permeability in tumor tissue and sustain tumor growth. More importantly, bradykinin antagonists such as HOE 140 may be beneficial for the inhibition of tumor growth.

Animals↗
PubMed1998

[Intrathoracic vagal nerve schwannoma preoperative diagnosis is correct because of clinical and characteristic CT findings--a case report and review of the literature].

A 60-year-old man was operated with the clinical diagnosis of intrathoracic vagal nerve schwannoma because of characteristic CT findings and no symptom of neurofibromatosis. Thoracoscopic surgery was performed and it was confirmed pathologically. Intrathoracic vagal nerve tumor is rare, so preoperative diagnosis seems to be difficult. We review the intrathoracic vagal nerve tumors reported in Japan (52 cases of schwannoma and 9 cases of neurofibroma), and analyzed the tumor location, furthermore, the relationship of neurofibromatosis and schwannoma and neurofibroma on vagal nerve tumor.

Humans↗
PubMed1998

Successful detection of active osteoclasts in situ by systemic administration of an osteoclast-specific monoclonal antibody.

Cell-surface proteins preferentially expressed on osteoclasts are thought to play important roles in the functional modulation of the osteoclasts. Recently, we found a novel cell-surface antigen designated Kat1-antigen (Kat1-Ag) specifically expressed on rat osteoclasts. It would be useful to regulate the functional activity of the osteoclasts directly via an osteoclast-specific antigen expressed on the cell surface of the osteoclasts. In order to establish the basis of such an application, in the present study we established a method for the direct detection of osteoclasts in situ by a systemic administration of the anti-Kat1-Ag monoclonal antibody (mAb Kat1) to rats, and we successfully detected functional osteoclasts in situ. Prior to performing in vivo experiments, we examined the reactivity of the mAb Kat1 to the isolated rat osteoclasts. Approximately 40-80% of the osteoclasts were reactive with mAb Kat1, suggesting that this mAb recognizes osteoclasts in a specific differentiation or functional state. Calcitonin treatment of osteoclast-like cells formed in vitro from bone marrow cells resulted in a conversion of Kat1-positive osteoclast-like cells into Kat1-negative multinucleated cells, showing the positive correlation between the Kat1-Ag expression and the potential bone-resorbing activity of osteoclasts. Administration of this lineage-specific mAb to the peritoneal cavity of newborn rats resulted in a successful recruitment of mAb Kat1 to the newly formed osteoclasts and functional osteoclasts in a highly specific manner. Detailed analysis by immunoelectron microscopy revealed that this mAb specifically bound to the basolateral side of the active osteoclasts, which were identified by their typical ruffled border and clear zone, whereas the mAb did not react to postfunctional osteoclasts. These findings demonstrate a high potential utility of mAb Kat1 in osteoclast-targeted regulation of bone remodeling.

Animals↗
PubMed1998

Apoptosis of photoreceptor cells in ornithine-induced retinopathy.

BACKGROUND: The intravitreal injection of ornithine produces selective damage to the retinal pigment epithelium (RPE) and results in a loss of RPE, choriocapillaris and photoreceptor cells. To elucidate the mechanism of secondary retinal atrophy, we investigated the presence of apoptotic cells in a rat model of ornithine-induced retinopathy. METHODS: At 6 and 12 h and 1, 2, 4, 7, 14 and 28 days after an intravitreal injection of L-ornithine hydrochloride in rat eyes, we removed the eyes and subjected them to histopathological examination. We detected apoptotic cells by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate digoxigenin nick end labeling (TUNEL) assay, which stains the 3'-OH ends of fragmented DNA. We used electron microscopy to detect the apoptotic cells morphologically. RESULTS: RPE cells were selectively damaged immediately after ornithine administration. TUNEL-positive photoreceptor cells appeared exclusively in the photoreceptor cell layer 12 h after ornithine administration. The number of TUNEL-positive cells increased throughout the 2 days following the injection, then decreased markedly. TUNEL-positive cells remained until 28 days, when the photoreceptor cells had disappeared. The ganglion cell layer, inner nuclear layer and damaged RPE cells were negative for TUNEL staining during all stages. The electron microscopic study also revealed the pyknotic nuclei of apoptotic photoreceptor cells. CONCLUSION: An intravitreal injection of ornithine caused primary damage to the RPE, and subsequently some of the photoreceptor cells revealed apoptosis by TUNEL assay. These findings suggest the dysfunction of the RPE causes photoreceptor cell death according to the intrinsic program of an apoptotic mechanism.

Animals↗
PubMed1998

Nucleotide sequence of the gene encoding the RNA polymerase and the 3' non-coding region of a bovine enterovirus Japanese isolate: rapid synonymous substitutions between European and Japanese strains.

The nucleotide sequences of the genome RNA encoding the RNA polymerase and the 3' non-coding region (NCR) of bovine enterovirus (BEV) serotype I Japanese isolate, MZ468, were determined. The genetic distance between the two BEV serotype I strains, MZ468 and VG-5-27, was calculated by pairwise comparison of nucleotide sequences. The synonymous substitution rate was high (1.40 x 10(-2)/site/year), and of the same order as those of influenza virus HA, HIV-1 gag and env, and enterovirus 70 VP1 genes.

Amino Acid Sequence↗
PubMed1998

Interstitial laser coagulation for management of benign prostatic hyperplasia: a Japanese experience.

PURPOSE: The principle of interstitial laser coagulation is to shrink the prostate by generating intraprostatic necrosis without damaging the urethra or causing tissue sloughing. The clinical efficacy and durability of interstitial laser coagulation in the treatment of benign prostatic hyperplasia (BPH) were evaluated. MATERIALS AND METHODS: From December 1993 to June 1996, 76 patients with symptomatic BPH were treated with interstitial laser coagulation. A neodymium:YAG laser was used in combination with a specially designed interstitial thermotherapy light guide. The tip of the light guide was inserted into each lobe of the prostate transurethrally under direct vision. All evaluations were made at baseline and then 1, 3, 6 and 12 months after therapy. Treatment outcome was evaluated by International Prostate Symptom Score (I-PSS), flow rate and post-void residual urine volume. Disease specific quality of life was assessed via a quality of life assessment score and a BPH impact index. Independent of symptom assessment, a self-reporting questionnaire was prepared at 3 months postoperatively regarding satisfaction with treatment and sexual function. RESULTS: Among 44 patients followed to 12 months the mean I-PSS significantly decreased from 20.4 at baseline to 7.4, representing 64% improvement (p <0.001). Peak flow rate increased by 50% from a preoperative average of 7.4 to 11.1 ml. per second at 12 months in 42 patients (p <0.001). The post-void residual volume decreased by 57% from 102 to 44 ml. at 12 months in 40 cases (p <0.001). Steady and progressive improvement was observed on quality of life assessment and BPH impact index scores at 3, 6 and 12 months. No patients reported new onset of erectile dysfunction. No serious side effects were observed, except for loss of ejaculation in 3 cases and seminal vesicle abscess in 1. Only 6 patients (8%) required re-treatment for persisting obstructive symptoms during 12 months of followup. A recent change in methods towards more aggressive treatment plausibly influenced the outcomes to require less repeat treatment. CONCLUSIONS: After the interstitial laser coagulation procedure satisfactory results were obtained and improvement lasted through 12 months. Although the optimal number of fiber placements for each prostate is not known, more aggressive treatment appears to provide better outcomes.

Aged↗
PubMed1998

Effect of the NO scavenger carboxy-ptio on endothelium-dependent vasorelaxation of various blood vessels from rabbits.

In the present study, we investigated the effect of a nitric oxide (NO) scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide [carboxy-PTIO], on endothelium-dependent relaxation of a series of blood vessels from rabbits, such as thoracic aorta and femoral, renal, mesenteric, and pulmonary arteries, using a functional muscle bath technique. Carboxy-PTIO produced concentration-dependent contractions in various vessels. The contractile responses in renal, mesenteric, and pulmonary arteries were significantly greater than those in the aorta and femoral artery. Similarly, phenylephrine-induced contractions in renal, mesenteric, and pulmonary arteries were markedly enhanced after pretreatment with carboxy-PTIO. Also, carboxy-PTIO inhibited acetylcholine-induced relaxation in various blood vessels. The maximum inhibitions in aorta and femoral artery were significantly greater than those in renal, mesenteric, and pulmonary arteries. The present data demonstrate that carboxy-PTIO reduces basal, phenylephrine-, and acetylcholine-induced release of NO in rabbit blood vessels. However, different degrees of inhibition of endothelium-dependent vasorelaxation were observed in various vessels. Specifically, the thoracic aorta and femoral artery are less susceptible to the action of carboxy-PTIO without acetylcholine than renal, mesenteric, and pulmonary arteries. Conversely, the most potent carboxy-PTIO-induced inhibition of acetylcholine-induced vasorelaxation was observed with aorta and femoral arteries. Thus, it is suggested that the contribution of endogenous NO to vascular tone and regional blood flow may vary among different rabbit blood vessels.

Acetylcholine↗
PubMed1998

Beneficial effects of acute and repeated administrations of sigma receptor agonists on behavioral despair in mice exposed to tail suspension.

In an attempt to examine whether sigma receptor agonists alleviate behavioral despair, we investigated the effects of sigma receptor agonists on the tail suspension-induced immobility in mice. The acute and repeated (14 days) administrations of sigma1 receptor agonists, such as 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (SA4503) (1 and/or 3 mg/kg) and (+)-pentazocine (5.6 mg/kg), sigma1/2 receptor agonists, such as 1,3-di(2-tolyl)guanidine (DTG) (3 and/or 5.6 mg/kg), desipramine (7.5 and/or 15 mg/kg), and fluoxetine (10 and/or 20 mg/kg), reduced immobility in mice exposed to tail suspension. N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl] ethylamine monohydrochloride (NE-100), a sigma1 receptor antagonist, significantly antagonized the decrease in immobility induced by acute administrations of SA4503 (1 mg/kg) and (+)-pentazocine (5.6 mg/kg). Although not significant, NE-100 showed a tendency to inhibit the DTG (5.6 mg/kg)-induced decrease in immobility. In contrast, repeated administrations of SA4503 (1 and 3 mg/kg), (+)-pentazocine (5.6 mg/kg) or DTG (5.6 mg/kg) failed to affect the increase in body weight. These results suggest that acute and repeated stimulations of sigma, possibly a sigma1 receptor subtype, alleviate behavioral despair, unaccompanied with changes in body weight.

Animals↗
PubMed1998

Intra-articular levels of prostaglandin E2, hyaluronic acid, and chondroitin-4 and -6 sulfates in the temporomandibular joint synovial fluid of patients with internal derangement.

PURPOSE: This study was conducted to measure the intra-articular levels of prostaglandin E2 (PGE2), hyaluronic acid, and chondroitin-4 and -6 sulfate in patients with temporomandibular joint (TMJ) internal derangement involving a closed lock, and to see if these levels correlate with the clinical or arthroscopic findings. PATIENTS AND METHODS: Fifteen female patients (16 joints) with a mean age of 36.7 years were diagnosed as having a closed lock by clinical examination and diagnostic MR imaging. The patient's subjective pain was assessed by a visual analog scale (VAS) and a pain questionnaire (pain score), and the interincisal opening was measured. TMJ aspirates were obtained by washing of the joint with saline containing vitamin B12 as a marker for calibration of data. The samples were assayed for PGE2 with a radioimmunoassay, and the concentrations of unsaturated disaccaride isomers of hyaluronic acid (delta di-HA), chondroitin-4 sulfate (delta di-4S), and chondroitin-6 sulfate (delta di-6S) were measured by high-performance liquid chromatography. Immediately after collection of the synovial aspirates, diagnostic arthroscopy was performed on all but three joints to evaluate the severity of synovitis and cartilage degeneration. The degree of arthroscopic pathology was scored quantitatively. Intra-articular levels of PGE2, delta di-HA(HA), delta di-4S(C4S), and delta di-6S(C6S) were compared with patient's age, mouth opening, VAS rating, pain scores, and arthroscopic scores for synovitis and cartilage degeneration. RESULTS: The PGE2 level did not correlate with the clinical or arthroscopic parameters. HA had a weak correlation with mouth opening (0.54). C4S and C6S were correlated with arthroscopic scores of TMJ degeneration (0.97, 0.89) and with age (0.75, 0.62). The ratio of C4S and C6S to HA was also correlated with the arthroscopic indices of degeneration (0.93, 0.8) and PGE2 level (0.74, 0.69), but not with age. CONCLUSION: The PGE2 level in the TMJ synovial fluid does not specifically reflect the intensity of pain or synovitis, but the detection of high concentrations of C4S and C6S, compared with the amount of HA, is a possible marker of proteoglycan degradation in the TMJ.

Adolescent↗
PubMed1998

Glycosaminoglycan components in temporomandibular joint synovial fluid as markers of joint pathology.

PURPOSE: This study investigated the correlation between temporomandibular joint (TMJ) disease and the composition of glycosaminoglycans (GAGs) components in the synovial fluid (SF). MATERIALS AND METHODS: Synovial fluid (SF) was obtained from 30 TMJs of 28 female patients diagnosed as having a displaced disc with reduction (WR) (seven joints), a displaced disc without reduction (WOR) (13 joints), osteoarthritis (OA) (five joints), or rheumatoid arthritis (RA) (five joints) by MR imaging and clinical examination. After the SF was directly aspirated, It was digested with chondroitinase ABC and hyaluronidase, and the concentration of unsaturated disaccharide isomers of chondroitin 6-sulfate (delta di-6S), chondroitin 4-sulfate (delta di-4S) and hyaluronic acid (delta di-HA) were measured by high-performance liquid chromatography (HPLC) combined with fluorometry. The ratio of delta di-6S or delta di-4S to delta di-HA, and delta di-6S to delta di-4S, were calculated. RESULTS: There were no significant differences in concentrations of delta di-6S, delta di-4S, or delta di-HA among the groups. The ratio of delta di-6S to delta di-4S was 2.7 +/- 1.4 in OA, 2.6 +/- 0.9 in joints with WOR, 2.9 +/- 1.2 in joints with WR, and 1.3 +/- 0.4 in RA synovial fluid. Differences in the delta di-6S: delta di-4S ratio between RA and the other conditions were statistically significant (P < .05). CONCLUSION: These results suggest that the delta di-6S:delta di-4S ratio in the synovial fluid of the TMJ reflects the proteoglycan metabolism of the joint tissues, particularly of the articular cartilage and synovial tissue. This ratio could be used to diagnose joint diseases and to predict articular cartilage destruction or synovial proliferation caused by these diseases.

Adult↗