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Biomedical subjects

M Maeno

Publications and source records attributed to M Maeno.

At least 19 recordsLinked to original sources
PubMed1998

Classification of Lactobacillus helveticus strains by immunological differences in extracellular proteinases.

Polyclonal antibodies against an extracellular proteinase of Lactobacillus helveticus CP53 were raised. The antibodies reacted with a 170-kDa enzyme with activity and a 53-kDa protein that seemed to be a degradation product of the 170-kDa proteinase from results of immunoblotting. The antibodies reacted also with a 45-kDa extracellular proteinase of L. helveticus CP790. However, monoclonal antibodies to the CP790 proteinase did not react with the proteinase of L. helveticus CP53. Seventeen strains of L. helveticus were tested for immunological reactivity with the two kinds of antibodies. The strains all had the same reactivity as either strain CP53 or strain CP790. Eleven strains with the 45-kDa proteinase were identified as L. helveticus biovar jugurti because they did not ferment maltose, four other strains with the 170- and 53-kDa proteins were identified as L. helveticus biovar helveticus because they fermented maltose. The remaining two strains dit not fit this pattern; they had both the 170- and 53-kDa proteins, but classification by their sugar utilization showed them to be L. helveticus biovar jugurti.

Animals↗
PubMed1997

Noninvasive identification of left ventricular involvements in arrhythmogenic right ventricular dysplasia: comparison of 123I-MIBG, 201TlCl, magnetic resonance imaging and ultrafast computed tomography.

We examined the feasibility of myocardial 123I-MIBG, 201TlCl, magnetic resonance imaging (MRI) and ultrafast computed tomography (UFCT) for the early detection of left ventricular involvements in 15 patients with arrhythmogenic right ventricular dysplasia (ARVD). Radionuclide ventriculography (RNV) and myocardial imaging with 123I-MIBG, 201TlCl, MRI and UFCT were performed in all 15 patients and in 10 normal subjects. The patients' scans were visually interpreted by two nuclear medicine physicians taking into consideration the extent score (ES) and severity score (SS) calculated by using the bull's-eye view in relation to normal data derived from the normal subjects. The left ventricular ejection fraction (LVEF) was measured by RNV. Fourteen (93%) patients showed regional 123I-MIBG defects, while 12 (80%) patients showed regional 201TlCl defects. The ES and SS were higher in 123I-MIBG than 201TlCl (ES: 31.5 +/- 18.5 vs. 17.5 +/- 18.2, p < 0.01, SS: 34.8 +/- 42.2 vs. 16.9 +/- 37.5, p < 0.01). Abnormal UFCT and MRI findings suggesting fatty involvements of the LV myocardium were demonstrated in 7 patients (Group B), while 7 patients showed regional 123I-MIBG defects without abnormal UFCT and MRI findings (Group A). 123I-MIBG was significantly more sensitive than UFCT and MRI (p < 0.05), although one patient, an exception, showed abnormal UFCT findings for the apex of the LV myocardium without abnormal 123I-MIBG and MRI findings. The LVEF, as a measure of LV systolic function, was better preserved in Group A than in Group B (59.3 +/- 3.6 vs. 45.8 +/- 5.8, p < 0.01). The present findings indicated that myocardial imaging with 123I-MIBG sensitively detects myocardial damage in patients with ARVD in the early stage when cardiac systolic function is still preserved.

3-Iodobenzylguanidine↗
PubMed1997

Pubic osteolysis mimicking a malignant lesion: report a case with a fracture dislocation of the sacroiliac joint.

We report the case of a 67-year-old woman who presented to our institution with osteoblastic and osteolytic lesions of the pubis and fracture dislocation of the left sacroiliac joint. She had presented 7 months earlier to an outside institution with a left gluteal mass, which had been biopsied and had been believed to represent malignancy. A second biopsy at our institution showed no evidence of malignancy and was felt to represent fracture healing. A diagnosis of public osteolysis was made based on the radiographic and histologic findings. A follow-up radiograph 6 years after presentation revealed healing of the lesions, confirming its benignity.

Aged↗
PubMed1997

Immunohistochemical and biochemical characterization of sulphated proteoglycans in embryonic chick bone.

The type and distribution of sulphated proteoglycans (PGs) in the midshaft subperiosteal bone of 15-18-day embryonic chick femurs were studied immunocytochemically and biochemically, using four monoclonal antibodies (MAb 2B6, 3B3, 1B5, and 5D4). These MAb specifically recognize epitopes in chondroitin 4-sulphate (C4-S) and dermatan sulphate (DS); chondroitin 6-sulphate (C6-S) and unsulphated chondroitin (C0-S); C0-S; and keratan sulphate (KS) respectively. Immunohistochemistry showed that staining of C4-S, DS, and KS, but not of C6-S and C0-S, was limited to osteoid, the cell surface of osteocytes, and to the walls of osteocytic lacunae and bone canaliculi in 15-18-day embryonic specimens. However, no significant difference in the distribution and intensity of immunostaining was observed in these specimens. Bone proteins were extracted from fresh 18-day embryonic specimens with a three extraction procedure, 4 M guanidine HCl (GdnCl, G-1 extract), 0.4 M EDTA (E-extract), followed by GdnCl (G-2 extract), to characterize mineral binding and collagenous matrix associated PGs in E- and G2-extracts respectively. Western blot analysis of E- and G2-extracts demonstrated that chondroitinase ABC-digested PGs with a molecular weight (Mr) approximately of 45,000 containing GAGs predominantly corresponding to C4-S and/or DS, with no detectable C6-S or C0-S present in the mineral and matrix phase, whereas KSPGs having an Mr of approximately 72,000 are only present in the mineral phase. These results indicate that embryonic chick bone contains small PGs having C4-S, DS, and KS chains with preferential localization to osteoid, the cell surface of osteocytes, and to the walls of osteocytic lacunae and bone canaliculi.

Animals↗
PubMed1997

Feeding experiments of pyridoxine derivatives as vitamin B6.

In order to compare the nutritional effect of vitamin B6 derivatives, long-term feeding experiments with rats were carried out using pyridoxine-alpha-D-glucoside (PN-alpha-Glc), pyridoxine-beta-D-glucoside (PN-beta-Glc) or epsilon- (N-phosphopyridoxyl)lysine (PNP-Lys) with test diets consisting of basically the AIN-76 composition, except for the addition of 0.1 mg pyridoxine equivalent (PN eq.)/100 g diet. During 21 days of pair-feeding against the vitamin B6-deficient diet group, body weight gain, urinary excretion of xanthurenic acid and pyridoxic acid were measured. After the feeding experiment, rats were killed and examined in terms of liver kynureninase activity (EC 3.7.1.3) with and without adding exogenous pyridoxal 5'-phosphate (PLP), erythrocyte aspartate aminotransferase activity (EC 2.6.1.1), as well as PLP concentration in blood. Rats fed with PN-alpha-Glc grew well, relative to the PN group. On the contrary, PN-beta-Glc poorly served as vitamin B6 source, because average bioavailability was only about 22% in comparison to that of PN (100%). From this long-term feeding experiments, we have shown that PN-alpha-Glc (average bioavailability about 84%) is a good source of vitamin B6 similar to PN.

Animals↗
PubMed1996

The role of BMP-4 and GATA-2 in the induction and differentiation of hematopoietic mesoderm in Xenopus laevis.

Vertebrate embryonic blood formation is regulated by factors that participate in dorsal-ventral patterning and mesoderm induction. The GATA-binding transcription factors are required for normal hematopoiesis and are expressed during gastrulation when ventral mesoderm (VM) is induced to form blood. Based on the recent demonstration that bone morphogenetic protein (BMP-4) is a potent ventralizing factor and inducer of hematopoietic tissue, we hypothesized that GATA-2 could be induced or activated by BMP-4. Here we demonstrate that BMP-4 can stimulate GATA-2 expression, and that expression of a dominant negative BMP-4 receptor can suppress GATA-2 induction by BMP-4 in ventral mesoderm. Over-expression of GATA-2 in ventral mesoderm leads to increased globin production and forced expression of GATA-2 in primitive ectoderm adjacent to ventral mesoderm also stimulates globin expression. Our results suggest that BMP-4 and GATA-2 can function in two adjacent germ layers, mesoderm and ectoderm, to participate in blood cell formation during embryogenesis.

Animals↗
PubMed1996

Involvement of Ras/Raf/AP-1 in BMP-4 signaling during Xenopus embryonic development.

Previously, we elucidated the role of bone morphogenetic protein 4 (BMP-4) in the dorsal-ventral patterning of the Xenopus embryo by using a dominant negative mutant of the BMP-4 receptor (DN-BR). The present paper describes the involvement of Ras, Raf, and activator protein 1 (AP-1) in BMP-4 signaling during Xenopus embryonic development. The AP-1 activity was determined by injecting an AP-1-dependent luciferase reporter gene into two-cell-stage Xenopus embryos and measuring the luciferase activity at various developmental stages. We found that injection of BMP-4 mRNA increased AP-1 activity, whereas injection of DN-BR mRNA inhibited AP-1 activity. Similar inhibitory effects were seen with injection of mRNAs encoding dominant negative mutants of c-Ha-Ras, c-Raf, or c-Jun. These results suggest that the endogenous AP-1 activity is regulated by BMP-4/Ras/Raf/Jun signals. We next investigated the effects of Ras/Raf/AP-1 signals on the biological functions of BMP-4. DN-BR-induced dorsalization of the embryo, revealed by the formation of a secondary body axis or dorsalization of the ventral mesoderm explant analyzed by histological and molecular criteria, was significantly reversed by coinjection of [Val12]Ha-Ras, c-Raf, or c-Jun mRNA. Furthermore, the BMP-4-stimulated erythroid differentiation in the ventral mesoderm was substantially inhibited by coinjection with the dominant negative c-Ha-Ras, c-Raf, or c-Jun mutant. Our results suggest the involvement of Ras/Raf/AP-1 in the BMP-4 signaling pathway.

Animals↗
PubMed1996

Nature and distribution of chondroitin sulphate and dermatan sulphate proteoglycans in rabbit alveolar bone.

The type and distribution of mineral binding and collagenous matrix-associated chondroitin sulphate and dermatan sulphate proteoglycans in rabbit alveolar bone were studied biochemically and immunocytochemically, using three monoclonal antibodies (mAb 2B6, 3B3, and 1B5). The antibodies specifically recognize oligosaccharide stubs that remain attached to the core protein after enzymatic digestion of proteoglycans and identify epitopes in chondroitin 4-sulphate and dermatan sulphate; chondroitin 6-sulphate and unsulphated chondroitin; and unsulphated chondroitin, respectively. In addition, mAb 2B6 detects chondroitin 4-sulphate with chondroitinase ACII pre-treatment, and dermatan sulphate with chondroitinase B pre-treatment. Bone proteins were extracted from fresh specimens with a three-step extraction procedure: 4 M guanidine HCl (G-1 extract), 0.4 M EDTA (E-extract), followed by guanidine HCl (G-2 extract), to characterize mineral binding and collagenous matrix associated proteoglycans in E- and G2-extracts, respectively. Biochemical results using Western blot analysis of SDS-polyacrylamide gel electrophoresis of E- and G2-extracts demonstrated that mineral binding proteoglycans contain chondroitin 4-sulphate, chondroitin 6-sulphate, and dermatan sulphate, whereas collagenous matrix associated proteoglycans showed a predominance of dermatan sulphate with a trace of chondroitin 4-sulphate and no detectable chondroitin 6-sulphate or unsulphated chondroitin. Immunocytochemistry showed that staining associated with the mineral phase was limited to the walls of osteocytic lacunae and bone canaliculi, whereas staining associated with the matrix phase was seen on and between collagen fibrils in the remainder of the bone matrix. These results indicate that mineral binding proteoglycans having chondroitin 4-sulphate, dermatan sulphate, and chondroitin 6-sulphate were localized preferentially in the walls of the lacunocanalicular system, whereas collagenous associated dermatan sulphate proteoglycans were distributed over the remainder of the bone matrix.

Animals↗
PubMed1996

Identification of an antihypertensive peptide from casein hydrolysate produced by a proteinase from Lactobacillus helveticus CP790.

Casein hydrolysate, produced by an extracellular proteinase from Lactobacillus helveticus CP790, was fractionated by two-step reverse-phase HPLC. Only one fraction showed antihypertensive activity as measured by systolic blood pressure in spontaneously hypertensive rats after oral administration. Ten peptides in the fraction were further purified and identified by analysis of amino acid sequences. Each identified peptide was chemically synthesized, and the antihypertensive activity of each peptide was evaluated in spontaneously hypertensive rats. The synthetic peptide with a sequence of Lys-Val-Leu-Pro-Val-Pro-Gln, found in beta-casein, indicated strong antihypertensive activity from 2 to 10 h after oral administration of 2 mg of peptide/kg of BW, and the effect was maximal at 6 h after oral administration (-31.5 +/- 5.6 mm Hg). Moreover, the antihypertensive effect of the peptide was dependent on the dosage of peptide from 0.5 to 2 mg of peptide/kg of BW. Interestingly, the antihypertensive peptide showed lower inhibitory activity of angiotensin I-converting enzyme, but the activity was increased after pancreatin digestion.

Amino Acid Sequence↗
PubMed1996

Comparative study of pyridoxine-alpha, beta-glucosides, and phosphopyridoxyl-lysine as a vitamin B6 nutrient.

The nutritional effects of pyridoxine-alpha-glucoside (PN-alpha-Glc), pyridoxine-5' beta-glucoside (PN-5' beta-Glc) and epsilon-N-(phosphopyridoxyl)-lysine (PNP-Lys) were examined by means of: 1) transport across the intestinal wall using everted rat intestine, 2) metabolic conversion by liver or kidney homogenate, and 3) oral administration of the compound to B6-deficient rats and the subsequent analysis of B6 derivatives found in plasma. Using everted sacs prepared from rat small intestine, PN-alpha-Glc was transported into the serosal side in its intact form. On the other hand, a part of PN-5' beta-Glc was found as PN on the serosal side (PN-5' beta-Glc: PN = 2:1). When PN-alpha-Glc, PN-5' beta-Glc or PNP-Lys was incubated with liver or kidney homogenate for 3 h at pH 6.0, PN-alpha-Glc was hydrolyzed to PN (6%), while there was no hydrolysis of PN-5' beta-Glc. After 30 min of administration of each B6 derivative to B6-deficient rats, blood was collected from the heart, and the B6-derivatives found in plasma were analyzed. It was ascertained that PN-alpha-Glc served as well as PN as a B6 nutrient, while PN-5' beta-Glc and PNP-Lys were not easily metabolized to the coenzyme form, pyridoxal 5'-phosphate.

Animal Nutritional Physiological Phenomena↗
PubMed1996

[Significance of 123I-metaiodobenzylguanidine SPECT for detecting left ventricular involvement in patients with arrhythmogenic right ventricular dysplasia].

The right ventricle being primarily involved in ARVD, recent reports indicate the presence of histological and functional abnormalities in the left ventricle for some patients with ARVD. The aim of this study was to evaluate the significance of myocardial sympathetic dysfunction as an early sign of left ventricular (LV) involvement by 123I-MIBG (MIBG) SPECT and to compare the findings with those of 201TlCl (Tl) SPECT, radionuclide left ventriculography, ultrafast computed tomography (UFCT), magnetic resonance imaging (MRI) and echo-cardiography in 10 patients (pts) with ARVD. MIBG defects in LV regions were detected in 9 pts. Seven of the 9 pts showed MIBG defects in LV regions adjacent to RV. The subjects were divided into 2 groups based on left ventriculography, 5 with normal LVEF (> 55%) and 5 with reduced LVEF. In the normal LVEF group, 4 pts showed MIBG defects and 2 pts showed TI defects, and MIBG defects were larger than TI defects (ES: 14 +/- 6 vs. 5 +/- 7, p <0.05). In reduced LVEF group, all of 5 pts showed MIBG and TI defects, and MIBG defects were larger than TI defects (ES: 42 +/- 12 vs. 25 +/- 3, p <0.05). In comparison with normal LVEF group, reduced LVEF group showed larger and more severe MIBG defects (ES: 42 +/- 12 vs. 14 +/- 6, p <0.01, SS: 44 +/- 31 vs. 8 +/- 7, p <0.05). UFCT and MRI showed abnormal findings indicating LV fatty infiltration in only 3 of reduced LVEF group. Thus, MIBG showed abnormal distributions in the left ventricle with the highest frequency in all these modalities. These results suggest that MIBG SPECT provides a sensitive marker for detecting LV involvement in ARVD. Also, the extent of MIBG distribution abnormalities is helpful in assessing the severity of left ventricular involvement in patients with ARVD.

3-Iodobenzylguanidine↗
PubMed1995

Gadolinium-enhanced magnetic resonance imaging in acute myocardial infarction.

To investigate the clinical application of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) in the management of acute myocardial infarction (AMI), we examined 44 patients with AMI within 1 month after onset. Enhanced images were classified into 4 types: nontransmural (type 1), transmural and homogeneous (type 2), transmural and marginal (type 3), and no enhancement (type 4). Each enhancement pattern was correlated with angiographic and thallium-201 imaging results. The redistribution images of thallium were graded on a 4-point scale from 0 (normal) to 3 (markedly reduced or absent activity). The percentage of the perimeter affected by asynergy was obtained from the left ventriculogram. Peak creatine kinase and the percentage of asynergic perimeter were significantly higher in type 3 than in other type patients. End-diastolic volume index was significantly higher in type 3 than in type 2 patients. Left ventricular ejection fraction was lowest, and end-systolic volume index, thallium-201 score, and incidence of wall thinning on MRI were highest in type 3 patients. Therefore, the transmural and marginal enhancement pattern (type 3) was compatible with extensive myocardial infarction with infarct expansion and less viable myocardium. In the other types, the infarction was small to moderate in size and left ventricular function was well preserved. Thus, Gd-DTPA-enhanced MRI may be useful in the evaluation of left ventricular function and myocardial viability of the infarct region after AMI.

Aged↗
PubMed1995

Expression of the human interleukin 6 receptor alpha-chain in Xenopus laevis oocytes.

We investigated the biochemical properties of the 80 kDa binding subunit (gp80) of the human interleukin 6 receptor (IL-6R) in the genetic environment of the amphibian Xenopus laevis. In vitro transcribed mRNA encoding full length human gp80 was microinjected into Xenopus laevis stage VI oocytes. Protein expression was monitored by iodinated IL-6 and human gp80-specific monoclonal antibodies (mAb) PM1 and MT18. Maximal IL-6 binding activity was observed between 36-42 h after injection. Scatchard analysis indicated that gp80-injected oocytes expressed two independent classes of IL-6 binding sites of high- (Kd1 = 9 x 10(-11) M, 20 x 10(6) sites/cell) and low-affinity (Kd2 = 2 x 10(-9) M, 70.3 x 10(6) sites/cell). PM1 but not MT18 completely inhibited IL-6 binding to injected eggs. Our data suggest that the human IL-6R alpha-subunit gp80 is sufficient to confer high- and low-affinity IL-6 binding to Xenopus laevis oocytes.

Animals↗
PubMed1995

[Characteristics of regional sympathetic dysfunction in acutely ischemic myocardium assessed by 123I-metaiodobenzylguanidine imaging: impairment of myocardial norepinephrine uptake or retention].

To characterize regional cardiac sympathetic dysfunction due to myocardial ischemia, we examined 123I-metaiodobenzylguanidine (MIBG) myocardial distribution of initial 15-min and 4-hr delayed SPECT images in 14 patients with recent myocardial infarction (MI), 25 patients with vasospastic angina which was angiographically proven with elgonovine maleate (Gp VSAP) and 16 patients with chest pain syndrome and normal CAG findings (GpCP). In those with MI, the study was serially done at 2 weeks after (Gp MI-1) and at 3 months after the onset of MI (Gp MI-2). We estimated regional tracer uptake in 20 segments of tomographic images by using a 4-point scoring system (0 = normal, 1 = mild, 2 = moderate, 3 = severe reduction) and calculated the total defect score (IDS). In all patients with MI, the area of reduced MIBG uptake was more extensive than the 201Tl perfusion defect in the acute stage (Gp MI-1) indicating the presence of viable but denervated myocardial tissue. Also, the MIBG defect was persistently observed from initial (TDS: 24 +/- 13) to delayed imaging (TDS: 26 +/- 12). However, in the chronic stage (Gp MI-2), the initial MIBG uptake improved (TDS: 18 +/- 9) but the delayed uptake remained almost the same (TDS: 22 +/- 10) indicating high washout of MIBG from the ischemic myocardium. Fourteen in Gp VSAP and 14 in Gp CP showed the regional MIBG defect in the delayed image more extensively than in the initial image indicating high washout of MIBG in the involved myocardial regions. These results suggest that neuronal uptake of MIBG is impaired in the acute stage of MI although neuronal retention of MIBG is predominantly impaired in the chronic stage of MI or in Gps VSAP and CP.

3-Iodobenzylguanidine↗
PubMed1994

Myocardial involvement in patients with sarcoidosis. An analysis of 75 patients.

The authors studied 75 nonselected patients (30 men and 45 women; mean age 48 years) with sarcoidosis retrospectively to assess the applicability of nuclear examinations for detecting myocardial involvement. All patients were studied with Tl-201 myocardial perfusion scan (TMPS), Ga-67 myocardial scan (GMS), and left ventricular ejection fraction (LVEF) using ECG-gated radionuclide ventriculography. The positive GMS group had a significantly higher occurrence of abnormality on TMPS (100%) than the negative GMS group (41%). Patients with TMPS abnormality and positive GMS showed significantly lower LVEF (36.3%) than those of normal perfusion or negative GMS. When LVEF decreased, occurrences of TMPS abnormality and positive GMS increased. The authors demonstrate that in patients with sarcoidosis LVEF was closely related to TMPS and GMS, and LVEF reflected the progression of sarcoid heart disease and can be considered a reliable indicator of cardiac function. Patients with sarcoidosis with TMPS abnormality and positive GMS should be thought to have myocardial sarcoidosis and their cardiac functions can be assessed by ECG-gated radionuclide ventriculography, while the remaining patients should be examined with TMPS and GMS periodically for detection of myocardial involvement.

Adult↗
PubMed1994

In vivo monitoring system for structure-function relationship analysis of the antibacterial peptide apidaecin.

A unique antibacterial peptide derivative found in immune honeybee lymph, apidaecin 1b (AP1), was randomly mutagenized and characterized by a newly established system to analyze in vivo its structure-function relationship. Initially, a high-level expression host-vector system for AP1 in Escherichia coli was constructed by creating a fusion protein with the highly stable Streptomyces subtilisin inhibitor (SSI) molecule. Expression of the SSI-AP1 fusion protein was found to depend on the concentration of the transcriptional inducer isopropyl-beta-D-thio-galactopyranoside (IPTG) and to parallel the degree of growth inhibition of the transformant cells. Subsequently, apidaecin derivatives produced by localized random mutagenesis were screened with this IPTG concentration-controlled in vivo system by monitoring the growth inhibition patterns of the transformant cells. One mutant apidaecin (P9L) that had reduced activity was purified and isolated from the periplasmic fraction of an E. coli transformant. Its antibacterial activity was reduced to one-third of that of wild-type apidaecin. When considered together with the other mutations, it was concluded that several Pro residues, including that at the ninth position, are responsible for expression of the antibacterial action of apidaecin.

Amino Acid Sequence↗
PubMed1994

Change in blood levels of vitamin B-6 derivatives in pregnant and lactating rats.

By using an HPLC method which we have developed, concentration changes of vitamin B-6 derivatives in blood of pregnant and lactating rats were studied. PLP and PL were the main derivatives in plasma and erythrocytes, and occasionally, PMP was found in the plasma of rats fed a normal solid diet which contained 8.3 mg PN.HCl/kg diet. Upon pregnancy, the plasma PLP concentration decreased significantly (p < 0.01), whereas plasma PL tended to increase (p < 0.05). PLP concentration in erythrocytes tended to increase upon pregnancy. These results suggest that metabolism or utilization of vitamin B-6 is altered upon pregnancy and that plasma PLP concentrations alone may not be a good indicator of nutritional status. Further confirmation was needed for so from erythrocyte samples under our analytical conditions was not so from erythrocyte samples under our analytical conditions was not converted to PIC-P via PLP, after the sample was treated with glyoxylic acid and then with KCN.

Animals↗