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Biomedical subjects

R Maeda

Publications and source records attributed to R Maeda.

At least 37 records · Page 2Linked to original sources
PubMed2001

Identification and the role of soluble antigens detected in bile from Eimeria stiedai-infected rabbits.

Antibodies against Eimeria stiedai sporozoites and merozoites were detected in the sera of rabbits immunized with bile obtained from infected rabbits on the 15th day post-infection. The trails made by gliding sporozoites were also detected by the sera. After penetration into the host cell, an antibody-binding region was observed on the parasitophorous vacuole membranes of the parasites. Rabbits administered a combination of the bile and cholera toxin shed fewer oocysts in the feces after infection than control rabbits. The immunized rabbits developed a high level of IgA antibody against soluble antigens in the bile. By immunoblotting, antigens with molecular masses of 32, 37, and 49 kDa were detected in the bile obtained from infected rabbits on the 15th day postinfection. Absorption treatment with sporozoites reduced or abolished the antibody reactivity to the 32-kDa antigen of merozoites and the bile antigens. However, antibody reactivity to the 37- and 49-kDa antigens still remained. These results indicate that soluble antigens are present in the bile of rabbits in the acute phase of infection, and these may be produced and released by merozoites during the host cell invasion process.

Animals↗
PubMed2001

Isolation of Neospora caninum from the brain of a pregnant sheep.

Neospora caninum was isolated from the brain of a naturally infected pregnant sheep by inoculation of immunodeficient mice with a homogenate of the brain tissue. The ewe showed no clinical signs. Tachyzoites were observed in the tissues of the nu/nu mice injected with the brain tissue homogenate and the diagnosis was confirmed by immunohistochemical staining with anti-N. caninum antibodies and by detecting N. caninum-specific DNA by polymerase chain reaction.

Animals↗
PubMed2001

[Probability of the standardization of control survey in local medical association].

This report discusses about the probability of the standardization of external quality control (control survey) in local medical area such as prefecture size. For example, our control survey by Hiroshima medical association in Hiroshima prefecture is selected and shown on their effort to the standardization of the control survey. This Hiroshima control survey is continuing for 27 years and its purpose is the improvement of the differences between laboratory facilities. For the all standardization of control survey system, tests, devices and reagents, the recent reports of Hiroshima control survey shows that the reference methods by Japan Society of Clinical Chemistry (JSCC) and the enzyme reference materials by Japan Committee of Clinical Laboratory Standardization (JCCLS) are very useful for the improvement of the differences between laboratory facilities in Hiroshima Prefecture.

Chemistry, Clinical↗
PubMed2001

[The introduction of a new clinical laboratory system, so-called the profiles for each diagnosis related group].

We try to establish a new clinical laboratory system, so-called profiles for each diagnosis related group which have features as shown below. 1) The profiles are clinical manuals that are utilized by home doctors and show how to diagnose, follow up, observe complications and judge therapeutic effect. 2) The profiles are constructed on condition that they cover 60% of cases and cases that they cannot handle are supposed to be referred to the major hospitals or the specialized doctors. 3) The profiles are guaranteed to be reformed and maintained according to medical advancement. 4) The target diseases of the profiles are thyroid disease, liver diseases, diabetes mellitus, respiratory disease, infectious disease, renal disease, cardiac disease, hyperlipemia, collagen disease, hematological disease, osteoporosis and gynecological disease. We present the profiles for thyroid disease, hyperlipemia and collagen disease which have been accomplished.

Clinical Laboratory Techniques↗
PubMed2000

Quantitative analysis of microfilarial periodicity of Dirofilaria immitis in cats.

Microfilarial periodicity of Dirofilaria immitis in the venous blood of infected cats was analyzed by a trigonometric model. Cats were infected by subcutaneous transplantation with 120-day-old juvenile D. immitis. Microfilariae in the blood were first observed 98 days after transplantation. Blood was collected at 4h intervals for a 24h period, and examinations were repeated five times in two cats. The calculated periodicity index was 75.1 and 50.3 in these two cats. The estimated hour of peak microfilarial density ranged from 1.00 to 2.84h. Thus, the periodicity of microfilariae of D. immitis in the blood of cats was characterized as nocturnally sub-periodic.

Animals↗
PubMed2000

Active micromixer for microfluidic systems using lead-zirconate-titanate (PZT)-generated ultrasonic vibration.

A micromixer using direct ultrasonic vibration is first reported in this paper. The ultrasonic vibration was induced by a bulk lead-zirconate-titanate (PZT; 5 x 4 x 0.2 mm), which was excited by a 48 kHz square wave at 150 V (peak-to-peak). Liquids were mixed in a chamber (6 x 6 x 0.06 mm) with an oscillating diaphragm driven by the PZT. The oscillating diaphragm was in the size of 6 x 6 x 0.15 mm. Ethanol and water were used to test the mixing effectiveness. The laminar flows of ethanol (115 microL/min) and water (100 microL/min) were mixed effectively when the PZT was excited. The entire process was recorded using a video camera.

Animals↗
PubMed2000

Importance of OGTT for diagnosing diabetes mellitus based on prevalence and incidence of retinopathy.

Study was made on the necessity and importance of the oral glucose tolerance test (OGTT) for diagnosing diabetes mellitus based on prevalence and incidence of diabetic retinopathy. Subjects were 12208 persons undergoing OGTT between 1965 and 1997. The prevalence of retinopathy was significantly elevated with FPG>/=126 and 2-h PG>/=198 mg/dl. The incidence of retinopathy was 15-30/10000 person-years (PY) with FPG<125, but with FPG of 126-139 it was significantly higher (69/10000 PY) and at 140-199 mg/dl it was elevated to 139/10000 PY. Subjects were classified at initial test into FPG<110, 110-125, 126-139, and >/=140 and further into 2-h PG<200 and >/=200 mg/dl for comparison with the incidence of retinopathy. Even with the same FPG, the incidence was two- to threefold higher with 2-h PG>/=200 mg/dl, indicating that 2-h PG was highly associated with the incidence of retinopathy. As for IFG, the prevalence of diabetes as defined by 2-h PG>/=200 in the OGTT increased with elevated FPG, and 33.7% of IFG cases showed 2-h PG>/=200 mg/dl. Based on the prevalence and incidence of retinopathy, we conclude that 126 mg/dl FPG is an appropriate cut-off level, and the OGTT is important for diagnosing mild diabetes mellitus.

Adolescent↗
PubMed2000

Correlation among fasting plasma glucose, two-hour plasma glucose levels in OGTT and HbA1c.

A study was made on the association among 2-h plasma glucose (PG) in oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) using correlation and regression equation. Subjects were 13174 OGTT examinees tested between 1980 and 1998. Blood glucose was determined by the glucose oxidase method and glycated hemoglobin (HbA1c) by the HPLC method. As for correlation between 2-h PG and FPG, regression equation of the <60 year group was y=57.1+0.336x (r=0.866, P<0.0001) and that of the >==60 year group was y=61.5+0.286x (r=0.814, P<0. 0001). FPG was calculated at 124.3 in the <60 year group and 118.7 mg/dl in the >==60 year group for 2-h PG of 200 mg/dl, 2-h PG were calculated at 199.5 and 210.7 mg/dl for FPG of 126 mg/dl, respectively. In the <60 year group, FPG were calculated at 121.7 and 124.4 mg/dl and 2-h PG at 193.2 and 199.3 mg/dl for HbA1c of 6.0 and 6.1%, respectively. As for associations between HbA1c and FPG or 2-h PG being high correlation, it is possible to estimate a prevalence of DM in a group using HbA1c>==6.1%. High correlations were demonstrated among all the three measures; FPG, 2-h PG, HbA1c. If 2-h PG is used in diagnosing diabetes mellitus, an FPG of 126 mg/dl proposed by ADA and World Health Organization (WHO) as a diagnostic level of FPG is an acceptable value for the Japanese.

Adult↗
PubMed2000

Xenopus msx-1 regulates dorso-ventral axis formation by suppressing the expression of organizer genes.

We demonstrated previously that Xmsx-1 is involved in mesoderm patterning along the dorso-ventral axis, under the regulation of BMP-4 signaling. When Xmsx-1 RNA was injected into the dorsal blastomeres, a mass of muscle tissue formed instead of notochord. This activity was similar to that of Xwnt-8 reported previously. In this study, we investigated whether the activity of Xmsx-1 is related to the ventralizing signal and myogenesis promoting factor, Xwnt-8. Whole-mount in situ hybridization showed that Xmsx-1, Xwnt-8, and XmyoD were expressed in overlapping areas, including the ventro-lateral marginal zone at mid-gastrula stage. The expression of XmyoD was induced by the ectopic expression of either Xmsx-1 or Xwnt-8 in dorsal blastomeres, and Xwnt-8 was induced by the ectopic expression of Xmsx-1. On the other hand, the expression of Xmsx-1 was not affected by the loading of pCSKA-Xwnt-8 or dominant-negative Xwnt-8 (DN-Xwnt-8) RNA. In addition, Xmsx-1 RNA did not abrogate the formation of notochord if coinjected with DN-Xwnt-8 RNA. These results suggest that Xmsx-1 functions upstream of the Xwnt-8 signal. Furthermore, the antagonistic function of Xmsx-1 to the expression of organizer genes, such as Xlim-1 and goosecoid, was shown by in situ hybridization analysis and luciferase reporter assay using the goosecoid promoter construct. Finally if Xmsx-1/VP-16 fusion RNA, which was expected to function as a dominant-negative Xmsx-1, was injected into ventral blastomeres, a partial secondary axis formed in a significant number of embryos. In such embryos, the activity of luciferase, under the control of goosecoid promoter sequence, was significantly elevated at gastrula stage. These results led us to conclude that Xmsx-1 plays a central role in establishing dorso-ventral axis in gastrulating embryo, by suppressing the expression of organizer genes.

Actins↗
PubMed2000

Involvement of BMP-4/msx-1 and FGF pathways in neural induction in the Xenopus embryo.

The msx homeodomain protein is a downstream transcription factor of the bone morphogenetic protein (BMP)-4 signal and a key regulator for neural tissue differentiation. Xmsx-1 antagonizes the dorsal expression of noggin and cerberus, as revealed by in situ hybridization and reverse transcription-polymerase chain reaction assays. In animal cap explants, Xmsx-1 and BMP-4 inhibit the neural tissue differentiation induced by noggin or cerberus. A loss-of-function study using the Xmsx-1/VP-16 fusion construct indicated that neural tissue formation was directly induced by the injection of fusion ribonucleic acid, although the expression of neural cell adhesion molecule (N-CAM) in the cap was less than that in the cap injected with tBR or noggin. In contrast to the single cap assay, unexpectedly, both BMP-4 and Xmsx-1 failed to inhibit neurulation in the ectodermal explants to which the organizer mesoderm was attached. The results of cell-lineage tracing experiments indicated that the neural cells were differentiated from the animal pole tissue where the excess RNA of either BMP-4 or Xmsx-1 was injected, whereas notochord was differentiated from the organizer mesoderm. Neural tissue differentiated from BMP-4-injected ectodermal cells strongly expressed posterior neural markers, such as hoxB9 and krox20, suggesting that the posterior neural cells differentiated regardless of the existence of the BMP signal. The introduction of a dominant-negative form of the fibroblast growth factor (FGF) receptor (XFD) into the ectodermal cells drastically reduced the expression of pan and posterior neural markers (N-CAM and hoxB-9) if co-injected with BMP-4 RNA, although XFD alone at the same dose did not shut down the expression of N-CAM in the combination explants. Therefore, it is proposed that an FGF-related molecule was involved in the direct induction of posterior neural tissue in the inducing signals from the organizer mesoderm in vivo.

Animals↗
PubMed2000

New oral dosage form for elderly patients. III. Stability of trichlormethiazide in silk fibroin gel and various sugar solutions.

The hydrolysis of trichlormethiazide (TCM) in silk fibroin gel (SFG) prepared in various sugar solutions (such as ribose, fructose, mannose, and glucose solutions) was determined. The hydrolysis rate of TCM differed with the variety of sugars utilized in this study; that is, it decreased in the following order: ribose > fructose > mannose > glucose. To investigate the relationship between the hydrolysis rate of TCM and the physicochemical properties of the sugar molecule, the amount of unfrozen water of sugar molecules was calculated from differential scanning calorimetry (DSC). The amount of unfrozen water increased with an increase in the number of the equatorial OH groups n(e-OH) per sugar molecule that are able to hydrate favorably to the surrounding water molecules. The hydrolysis rate constant decreased with increase in n(e-OH); glucose, having a large n(e-OH) in this study could effectively stabilize TCM.

Administration, Oral↗
PubMed2000

Antibody reactivity to Cryptosporidium parvum in saliva of calves after experimental infection.

Antibodies against Cryptosporidium parvum in the saliva and sera of three calves experimentally infected with this parasite were examined by an indirect immunofluorescence antibody test and immunoblotting. Salivary anti-C. parvum IgA antibody appeared on day 12 post-challenge and had a tendency to increase transiently between days 15 and 30 post-challenge. Salivary anti-C. parvum IgG antibody levels showed a gradual increase along with the change in IgA antibody levels during the infection. In contrast, serum anti-C. parvum IgA antibody levels showed only a slight increase between days 15 and 30 post-challenge. Serum anti-C. parvum IgG antibody levels rose on day 12 post-challenge and one calf maintained relatively high level up to the end of the experiment. In immunoblotting, an antigen with a molecular mass of 15 kDa was found to react strongly to salivary IgA antibody and a 27 kDa antigen to react to serum IgG antibody.

Animals↗
PubMed1998

Positive and negative regulation of Easter, a member of the serine protease family that controls dorsal-ventral patterning in the Drosophila embryo.

The sequential activities of four members of the trypsin family of extracellular serine proteases are required for the production of the ventrally localized ligand that organizes the dorsal-ventral pattern of the Drosophila embryo. The last protease in this sequence is encoded by easter, which is a candidate to activate proteolytically the ligand encoded by spätzle. Here, we demonstrate biochemically that the zymogen form of Easter is processed in vivo by a proteolytic cleavage event that requires the three upstream proteases. Processed Easter is present in extremely low amounts in the early embryo because it is rapidly converted into a high molecular mass complex, which may contain a protease inhibitor. Easter zymogen activation is also controlled by a negative feedback loop from Dorsal, the transcription factor at the end of the signaling pathway. Each of these regulated biochemical processes is likely to be important in generating the ventral-to-dorsal gradient of Dorsal protein that organizes cell fates in the early embryo.

Animals↗
PubMed1997

XBMP-1B (Xtld), a Xenopus homolog of dorso-ventral polarity gene in Drosophila, modifies tissue phenotypes of ventral explants.

Previously we have isolated a Xenopus cDNA homolog of bone morphogenetic protein-1 (XBMP-1A). In the present report we describe a new cDNA clone called XBMP-1B (or Xtld) from a Xenopus embryonic library. Sequence analysis indicates that these two clones share an indentical N-terminal sequence, including a region of metalloprotease domain, three copies of a repeat first found in complement proteins C1r/s and an epidermal growth factor (EGF)-like sequence. XBMP-1B protein has an additional copy of an EGF-like sequence followed by two copies of complement 1 r/s repeat in the C-terminus. The overall protein structure predicted from the XBMP-1B sequence reveals that it encodes a protein homologous to Drosophila tolloid. Three XBMP-1 transcripts (2.9, 5.2 and 6.6 kb) were detected by northern blot analysis. However, the 2.9 kb transcript hybridized specifically with XBMP-1A and the 5.2 and 6.6 kb transcripts hybridized with XBMP-1B. In Drosophila, a major function of tolloid is to augment the activity of the decapentaplegic gene product, a close relative of tumor growth factor (TGF)-beta superfamily members, BMP-2/4. Although XBMP-1 and XBMP-4 are detected in various adult tissues of Xenopus, the expression pattern of these two genes was not tightly correlated. In the embryo, the expression of XBMP-1 increased gradually from the morula to the swimming tadpole stages. Injection of XBMP-1B RNA into the ventral blastomeres at the 4-cell stage caused an elongation of the ventral marginal zone explants and converted globin-positive blood cells to mesenchymal and muscle tissues at later stages. It was shown that XBMP-1A was less active and a 1A mutant lacking the signal sequence was inactive. Further studies revealed that injection of XBMP-1B RNA into the ventral marginal zone induced up-regulation of dorsal marginal zone markers, such as goosecoid and chordin, at the gastrulation stage. These data indicate that XBMP-1 may have a role in determining dorso-ventral patterning in Xenopus, but in a different way from the dpp/tolloid system demonstrated in Drosophila.

Amino Acid Sequence↗
PubMed1997

Xmsx-1 modifies mesodermal tissue pattern along dorsoventral axis in Xenopus laevis embryo.

This study analyzes the expression and the function of Xenopus msx-1 (Xmsx-1) in embryos, in relation to the ventralizing activity of bone morphogenetic protein-4 (BMP-4). Expression of Xmsx-1 was increased in UV-treated ventralized embryos and decreased in LiCl-treated dorsalized embryos at the neurula stage (stage 14). Whole-mount in situ hybridization analysis showed that Xmsx-1 is expressed in marginal zone and animal pole areas, laterally and ventrally, but not dorsally, at mid-gastrula (stage 11) and late-gastrula (stage 13) stages. Injection of BMP-4 RNA, but not activin RNA, induced Xmsx-1 expression in the dorsal marginal zone at the early gastrula stage (stage 10+), and introduction of a dominant negative form of BMP-4 receptor RNA suppressed Xmsx-1 expression in animal cap and ventral marginal zone explants at stage 14. Thus, Xmsx-1 is a target gene specifically regulated by BMP-4 signaling. Embryos injected with Xmsx-1 RNA in dorsal blastomeres at the 4-cell stage exhibited a ventralized phenotype, with microcephaly and swollen abdomen. Histological observation and immunostaining revealed that these embryos had a large block of muscle tissue in the dorsal mesodermal area instead of notochord. On the basis of molecular marker analysis, however, the injection of Xmsx-1 RNA did not induce the expression of alpha-globin, nor reduce cardiac alpha-actin in dorsal marginal zone explants. Furthermore, a significant amount of alpha-actin was induced and alpha-globin was turned off in the ventral marginal zone explants injected with Xmsx-1. These results indicated that Xmsx-1 is a target gene of BMP-4 signaling, but possesses a distinct activity on dorsal-ventral patterning of mesodermal tissues.

Animals↗