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T Maeda

Publications and source records attributed to T Maeda.

At least 577 records · Page 32Linked to original sources
PubMed1996

Assembly and function of Chlamydomonas flagellar mastigonemes as probed with a monoclonal antibody.

Mastigonemes are hair-like projections on the flagella of various kinds of lower eukaryotes. We obtained a monoclonal antibody (mAb-MAST1) to mastigonemes of Chlamydomonas reinhardtii, and found that it reacts with a single flagellar glycoprotein of about 230 kDa. Interestingly, immunofluorescence microscopy demonstrated that mAb-MAST1 recognizes not only the flagellar mastigonemes but also a ring composed of 10 or more particles located in the anterior end of the cell body close to the flagellar bases. The ring structure may be the pool of the mastigoneme protein. When the flagella are amputated, they regenerate to their original length in 90-120 minutes. We found that mastigonemes appear on the new flagellar surface as early as 15 minutes after deflagellation, and that new mastigonemes are mostly assembled onto the distal region of the flagellar surface. Mastigonemes thus appear to be inserted into the membrane only in the distal region of the flagellum. Alternatively, mastigonemes may be inserted at the base and transported very rapidly to the distal portion where they are trapped. When live cells are treated with mAb-MAST1, mastigonemes disappear from the flagellar surface. In these mAb-MAST1 treated cells, the swimming velocity decreases to 70-80% of the normal value, although the flagellar beat frequency increases to approximately 110% of the control. These findings demonstrate vectorial transport of mastigonemes to their assembly sites, and show that mastigonemes function to increase flagellar propulsive force by increasing the effective surface of the flagellum.

Animals↗
PubMed1996

Pharmaceutical studies for gene therapy: expression of human Cu, Zn-superoxide dismutase gene transfected by lipofection in rat skin fibroblasts.

To evaluate whether lipofection using Lipofectin is suitable for delivering foreign genes into skin fibroblasts as target cells, we performed experiments using human superoxide dismutase (hSOD) and neomycin-resistance (Neo) genes as models in rat skin fibroblasts (FR and primary cells) in vitro. The amounts of DNA used in the lipofection procedure significantly affected the transfection efficiencies, and the optimal amounts were determined for all cells used. However, the efficiencies in rat skin fibroblasts were about 20-fold higher than that in rat lung epithelial-like cells (L2 cells). The differences in plasmid vectors (pRc/RSV-SOD and pRc/CMV-SOD) hardly affected the transfection efficiencies. The amounts of Lipofectin significantly affected the transfection efficiencies, and the optimal amounts were determined for both types of skin fibroblasts. However, cytotoxic effects in both skin fibroblasts were observed with high doses of Lipofectin. On the other hand, with optimal amounts of DNA and Lipofectin, the reporter gene (NeoT) introduced into cells was mainly integrated into the host cell chromosome. Western blot analysis showed the continuous expression of hSOD protein for at least 45 d in skin fibroblasts transfected with the expression plasmid for hSOD by Lipofectin under the optimal conditions, and the cellular SOD activity fluctuated in parallel with the expression of hSOD protein. Differences in the type of cells also affected the expression of hSOD. These results indicate that it is necessary to set up optimal conditions for transfection using Lipofectin for each cell type, and that transfection with Lipofectin under optimal conditions may be an efficient method for introduction of foreign genes into skin fibroblasts for use as a clinical delivery system of therapeutic protein.

Animals↗
PubMed1996

Ice nucleus production of Fusarium moniliforme var. subglutinans in relation to its growth characteristics.

The effects of culture conditions on the ice nucleus production of Fusarium moniliforme var. subglutinans isolated from the gut of larvae of the rice stem borer (Chilo suppressalis Walker) were examined. The ice nucleus production was only affected by cultivation temperature and pH: the optimum temperature and pH were 15 degrees C to 20 degrees C and 4.0 to 6.0, respectively.

Asparagine↗
PubMed1996

Rapid coronary vasodilation by nitroglycerin tapes.

We analyzed the acute, direct effects of nitroglycerin (NTG) tape on the coronary arteries and hemodynamics in 38 patients who underwent coronary angiography. The diameters of the 3 main coronary arteries were compared among the angiograms obtained at baseline, 15 minutes following transdermal administration of 10 mg (8 patients) or 25 mg (30 patients) of NTG (Millisrol tape), and after intracoronary injection of 2.5 mg isosorbide dinitrate (ISDN). Only the left main trunk and proximal portion of the left anterior descending artery dilated after 10 mg of transdermal NTG administration (p < 0.05). However, every measured coronary segment (segments 1-8, 11, and 13) dilated (p < 0.05) after 25 mg of NTG. Systemic blood pressure decreased slightly but significantly from 150 +/- 22 to 147 +/- 21 mmHg during the study, with no change in heart rate. Left ventricular end-diastolic pressure decreased significantly from 16 +/- 7 to 14 +/- 5 mmHg. We conclude that 25 mg of transdermal NTG tape dilates coronary arteries and is applicable for acute coronary syndrome, with few complications.

Administration, Cutaneous↗
PubMed1996

Different localizations of growth-associated protein (GAP-43) in mechanoreceptors and free nerve endings of adult rat periodontal ligament, dental pulp and skin.

Distributions of growth-associated protein-43 (GAP-43) in the periodontal ligament and dental pulp of adult rats were studied by light and electron microscopy. The mature periodontal ligament and dental pulp contained numerous GAP-43-positive neural elements, comprising periodontal Ruffini endings and thin nerve fibers, but expression patterns differed among the kinds of nerves. In the periodontal ligament of rat molars, immunoelectron microscopy revealed that GAP-43 like immunoreactivity in the Ruffini ending, an essential mechanoreceptor, was confined to the Schwann sheaths around the axon terminals and was not in the axon terminals themselves, unlike free endings that revealed axonal GAP-43. However, the lamellar Schwann cells associated with the cutaneous receptors did not exhibit any GAP-43 like immunoreactivity though they were intensely reactive for low affinity nerve growth factor receptor (p75-NGFR), a marker for lamellar Schwann cells in mechanoreceptors. The characteristically uniform expression of GAP-43 in the Schwann lamellae that surround the Ruffini mechanoreceptors of rat molar ligament suggests that Schwann cells are involved in the GAP-43 mediated plasticity of these receptors. On the other hand, the pulpal nerves were filled with the reaction products in their axonal spaces, suggesting the potential for neuronal plasticity during normal function and after tooth injury.

Animals↗
PubMed1996

Ehlers-Danlos syndrome and congenital heart anomalies.

Two sisters with Ehlers-Danlos syndrome, inherited as an autosomal recessive trait, and congenital heart disease are herein reported. One was a 20-year-old woman with Ehlers-Danlos syndrome and multiple aphthous stomatitis, bronchial asthma, an emphysematous lung, a ventricular septal defect and a bilateral inguinal hernia due to hyperextensibility and joint hypermobility. The other was a 17-year-old girl with the same syndrome and an atrial septal defect, a ventricular septal defect and patent ductus arteriosus. The combination of Ehlers-Danlos syndrome and congenital heart anomalies in these siblings suggest a common genetic defect to be the cause of these diseases.

Adult↗
PubMed1996

Utility of the interval mapping technique using DNA pools of inbred mice.

We report an application of the interval mapping technique using DNA pools of inbred mice. The latest challenge in molecular genetics is to use microsatellite markers for gene mapping and cloning. Little is known about the interval mapping technique for detecting candidate linkages in inbred mice. We investigated the optimum interval length of microsatellite markers for gene mapping using DNA pools on mouse chromosomes, and found that between 25 and 35 centi Morgans (cM) was sufficient. We estimated that at least two to four microsatellite markers required for interval mapping should be present on each chromosome. The number required would depend entirely on the linkage map.

Animals↗
PubMed1996

Distinct structural requirements for interaction of the integrins alpha 5 beta 1, alpha v beta 5, and alpha v beta 6 with the central cell binding domain in fibronectin.

At least 10 different members of the integrin family have been reported to bind to fibronectin, and eight of these interact with the arginine-glycine-aspartic acid (RGD) site in the tenth type III repeat. However, studies utilizing recombinant fibronectin fragments have shown that for three of these, alpha 5 beta 1, alpha IIb beta 3, and alpha v beta 3, the structural requirements for binding to fibronectin differ. In the present study, we report that two additional integrins, alpha v beta 6, and alpha v beta 5 also demonstrate unique requirements for interaction with recombinant fibronectin fragments, alpha v beta 6, like alpha v beta 3, can support cell adhesion to the RGD-containing tenth repeat alone, and does not require the presence of a synergy site in the adjacent ninth repeat. In the cells used in this study, alpha v beta 5 only minimally supported adhesion to intact fibronectin, but did support adhesion to fragments composed of the eighth, ninth and tenth repeats or the tenth repeat, alone. Mutant fragments in which the eighth and tenth repeats were adjacent to one another enhanced adhesion mediated by alpha v beta 5, as well as adhesion mediated by alpha v beta 6. alpha v beta 5 and alpha v beta 6-mediated adhesion to all fibronectin fragments required interaction with the RGD site, as inferred by inhibition of adhesion with an RGD-containing peptide. These data suggest that each integrin that interacts with the RGD site in fibronectin has unique structural requirements for this interaction.

Antigens, Neoplasm↗
PubMed1996

[A case of superior vena cava syndrome treated with combination radiation and CRE (CBDCA and VP-16) therapy].

Carboplatin and etoposide were reported to be excellent radiation sensitizers. We encountered a patient with SVC syndrome due to lung cancer who was successfully treated by combination carboplatin, etoposide and hyperfractionation radiotherapy. A 72-year-old man was admitted to our hospital because of remarkable face edema. Computed tomography revealed a huge lung tumor and compressed SVC due to tumor growth. Acute tumor regression was essential for this case. We performed combination chemotherapy and radiation. The regime consisted of CBDCA 300 mg (day 1 1 hr drip infusion) and etoposide 50 mg/day for 21 days by oral administration. Two daily fractionations of 1.4 Gy were delivered 5 days-a-week, with a 4 h interval between fractions (total dose 49.8 Gy). Complete response of huge tumor was attained in this case. The major side effect associated with the therapy was myelosuppression. The patient's quality of life has been remarkably improved with this therapy.

Aged↗
PubMed1996

Patterns of epidermal growth factor receptor amplification in malignant gliomas.

Amplification of the gene for epidermal growth factor receptor (EGFR) is a common finding in malignant gliomas. We found that 18 of 29 grade 3 and grade 4 gliomas had EGFR amplification when assayed using fluorescence in situ hybridization. The amplification pattern suggests that the amplicon is contained within double minute chromosomes in most cases. EGFR copy number can differ by 20-fold in amplified cells within a single case. Polysomy 7 occurs frequently in both EGFR-amplified and -unamplified cells. More than one-third of the cases had < or = 10 percent of cells with amplified EGFR, and it is likely that these cases would not have been identified by methods that do not examine DNA on a cell by cell basis.

Brain Neoplasms↗
PubMed1996

Localization of human placental glucose transporter 1 during pregnancy. An immunohistochemical study.

To elucidate the potential roles of glucose transporter 1 (GLUT1) in human placenta during pregnancy, we examined the localization of GLUT1 in human placenta at various stages by immunohistochemistry with an anti-GLUT1 antibody by use of both light and electron microscopy. Specific staining for GLUT1 was localized on the apical brush border and along the basal plasma membrane of the syncytiotrophoblasts. The staining at the apical side was more intense than that at the basal side during the early stages of gestation. In later gestational stages, however, the staining pattern at the apical side became blurred and the staining intensity at the basal side increased. The cytotrophoblasts, seen embedded in the basal part of the syncytiotrophoblasts, seemed to show immunoreactivity for GLUT1 along the plasma membranes at the light-microscopic level. However, immuno-electron microscopic analysis with either pre- or post-embedding methods revealed that specific staining for GLUT1 was hardly observed on the cytotrophoblasts, but the cytotrophoblasts were often surrounded by immunoreactive processes of syncytiotrophoblasts. The blood capillaries and erythrocytes in the stroma of placental villi were always immunoreactive for GLUT1 throughout pregnancy. These findings suggest that GLUT1 may play a vital role in human pregnancy.

Capillaries↗
PubMed1996

[The perinatal risk factors and periventricular leukomalacia (PVL) in premature infants--relationship between fetal heart rate decelerations and PVL].

Periventricular leukomalacia (PVL) has recently been recognized as an important risk factor of neurological impairment in premature infants. We studied 29 PVL cases on perinatal risk factors comparing with a non-PVL matched control group retrospectively. Variable decelerations were more frequently observed with statistical significance in the PVL group in the intrapartum period. Then another study was conducted to evaluate the relationship between fetal heart rate (FHR) decelerations and cystic PVL prospectively. Since January 1993 through December 1994 we studied 209 low birth weight infants (31.1 +/- 3.2 weeks, 1,424 +/- 419 g) who had been subjected to intrapartum FHR monitoring and postnatal sonographic intracranial examinations sequentially every 7 days until discharge. Cystic PVL was detected in 6 of 209 cases (2.9%) and occurred only in infants who had revealed severe variable deceleration or prolonged deceleration (6/37, 16%) in intrapartum FHR monitoring. We conclude that in low birth weight infants intrapartum severe variable deceleration or prolonged deceleration might play a causal role in cystic PVL.

Bradycardia↗
PubMed1996

The expression of cytokeratins 7, 19, and 20 in primary and metastatic carcinomas of the liver.

We performed immunohistochemical studies on 90 surgically resected liver tumors, including 30 tumors each from hepatocellular carcinoma (HCC), cholangiocarcinoma (CC), and metastatic colorectal adenocarcinoma (MCA), using monoclonal antibodies against cytokeratin (CK) 7, CK 19, and CK 20 to examine the differences in the CK expressions in primary and metastatic carcinomas of the liver. We also investigated the usefulness of such expression in the differential diagnosis in addition to existing markers such as alpha-fetoprotein, carcinoembryonic antigen, and carbohydrate antigen 19-9. For CK 7, all except for one (97%) of the CCs were diffusely positive, whereas only two (7%) HCCs and one (3%) MCAs were diffusely positive. For CK 19, 23 (77%) CCs and 19 (64%) MCAs were diffusely positive, whereas no HCCs were positive. For CK 20, 22 (74%) MCAs were diffusely positive, whereas no HCC and three (10%) CCs were diffusely positive. The findings concerning the expression of immunohistochemical CK are therefore considered to be useful in addition to the diagnostic criteria when making a differential diagnosis of primary and metastatic carcinomas of the liver.

Adenocarcinoma↗
PubMed1996

Effects of estrogen and progesterone on plasma platelet-activating factor-acetylhydrolase activity and low-density lipoprotein cholesterol concentration in men.

OBJECTIVE: We examined the effects of estrogen and progesterone on the plasma platelet-activating factor (PAF)-acetylhydrolase activity and lipoprotein concentrations in men. METHOD: Ten healthy men received 6 days of oral mestranol (0.24 mg/day) followed by 6 days of oral norethisterone (20 mg/day). The PAF-acetylhydrolase activity and lipoprotein profiles were determined in each subject prior to and following mestranol loading and following norethisterone administration. RESULT: The mestranol caused a significant decrease in both the plasma PAF-acetylhydrolase activity and the low-density lipoprotein (LDL) cholesterol concentrations of 26.4% and 26.9%, respectively; norethisterone appeared to revert the PAF-acetylhydrolase activity and LDL cholesterol concentrations to the levels observed prior to mestranol loading. In addition, the plasma PAF-acetylhydrolase activity was positive correlated with the LDL cholesterol concentration (r = 0.58, P < 0.001). CONCLUSION: The results of this study indicate that mestranol and norethisterone exert an effect on the plasma PAF-acetylhydrolase activity in men, possibly by influencing plasma LDL cholesterol concentrations.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1996

Effects of parathyroidectomy and calcium supplementation on the pressor response to angiotensin II in conscious rats.

OBJECTIVE: We evaluated the effect of parathyroidectomy (PTx) and of calcium supplementation on the pressor response to angiotensin II (Ang II) in conscious rats. STUDY DESIGN: PTx and sham surgery were performed on 10-week-old male Wistar rats. The mean arterial pressure (MAP), heart rate, and the effective pressor dose of Ang II (EPD) which defined as the dose of Ang II required to elicit a rise of 20 mmHg in MAP, were evaluated in PTx and sham operated rats. Intracellular free calcium in platelets was assessed with the fluorescent dye, fura-2 acetoxymethyl ester. In addition, after administering a dose of supplemental calcium chloride, a 10, 20, or 40 mg/rat, we determined the changes in the MAP, EPD, and serum calcium level. RESULTS: The EPD in the PTx rats was significantly lower than the sham operated rats. The serum concentration of calcium in PTx was also significantly lower than the sham operated rats. A statistically significant negative relationship was observed between the EPD and intracellular free calcium in PTx rats. Following administration of 20 mg of calcium chloride (7.4 mg of elemental calcium) to the PTx rats, the EPD returned to the level seen in sham operated rats. CONCLUSION: Results suggest that a depletion of parathyroid hormone is associated with the pressor response to Ang II, and is involved in the regulation of intracellular free calcium.

Angiotensin II↗
PubMed1996

[Experimental techniques for developing new drugs acting on dementia (11)--Experimental methods on glutamate neurotoxicity].

Glutamate-induced neurotoxicity was examined in cultured rat cortical cells. Primary cultures were obtained from the cerebral cortex of fetal rats (17-19 days of gestation). Single cells dissociated from the cerebral cortex were plated on plastic coverslips placed in 35- or 60-mm culture dishes. Cultures were incubated in Eagle's minimal essential medium supplemented with 10% fetal calf serum or 10% horse serum at 37 degrees C in a humidified 5% CO2 atmosphere for 10-14 days. The neurotoxicity induced by glutamate was quantified by trypan blue exclusion. The viability of cultures was markedly reduced by a 10-min exposure to glutamate followed by incubation with glutamate-free medium for 1-24 hr. Glutamate neurotoxicity was prevented by the N-methyl-D-aspartate (NMDA) receptor antagonists, MK-801, 3-[(+/-)-2-carboxypiperazin-4-yl] propyl-1-phosphoric acid (CPP), ifenprodil and 7-Cl-kinurenate. Glutamate neurotoxicity was augmented by phorbol dibutyrate, that activates protein kinase C (PKC), but reduced by H-7, that inhibits PKC. These results suggest that PKC plays an important role in NMDA receptor-mediated glutamate neurotoxicity in the cerebral cortex.

Animals↗