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T Maeda

Publications and source records attributed to T Maeda.

At least 865 records · Page 48Linked to original sources
PubMed1991

A possible mechanism of mechanoreception in Ruffini endings in the periodontal ligament of hamster incisors.

The topographical relationship between Ruffini endings and the surrounding collagen fibers in the periodontal ligament of hamster incisors was investigated by means of both immunohistochemistry for neurofilament protein (NFP) and electron microscopy. Periodontal Ruffini endings, a type of stretch receptor, were present exclusively in the alveolar half of the periodontal ligament. Their axon terminals were densely and regularly associated with transverse collagen fibers, possibly forming a mechanoreceptive complex. Since blood sinuses with frequent anastomoses extended throughout the alveolus-related part, the densely innervated collagen bundles were separated from each other by the vascular spaces. Electron microscopic observation of specimens stained with tannic acid revealed a linkage between the axon terminals of the Ruffini endings and the surrounding collagen filaments. The axon terminals were enveloped by multiple layers of the basal lamina, which were penetrated by collagen filaments. The irregularly arranged collagen filaments were sandwiched between electron-dense laminae of the multilayered basal lamina. The possible mechanism of mechanoreception by the periodontal Ruffini endings is discussed on the basis of the immunohistochemical and ultrastructural findings.

Animals↗
PubMed1991

Similarity and difference in the mechanisms of neonatally induced tolerance and cyclophosphamide-induced tolerance in mice.

The mechanisms of cyclophosphamide (CP)-induced tolerance were investigated by comparing with those of neonatally induced tolerance. When C3H/He Slc (C3H; H-2k, Mls-1b) mice were given i.v. either AKR/J Sea (AKR; H-2k, Mls-1a) or (AKR x C3H)F1 (AKC3F1; H-2k, Mls-1a/b) spleen cells and treated i.p. with CP 2 days later, a long-lasting skin allograft tolerance to AKR was induced in each case without any signs of graft-vs-host disease (GVHD). However, typical signs of GVHD were observed in the C3H mice neonatally tolerized with AKR spleen cells, but not in those tolerized with AKC3F1 spleen cells. The expression of TCR V beta 6, which is strongly correlated with the reactivity to Mls-1a Ag (of donor AKR origin), in the periphery was quite different between the two types of tolerant C3H mice. Namely, in the lymph nodes of the C3H mice tolerized with AKR spleen cells and CP, only CD4(+)-V beta 6+, but not CD8(+)-V beta 6+, T cells selectively disappeared, whereas both of them were abrogated in the lymph nodes of the C3H mice neonatally tolerized of AKR. By contrast, in the thymus of the two types of tolerant C3H mice, both CD4+CD8- and CD4-CD8+ single-positive thymocytes expressing TCR V beta 6 were clonally deleted, suggesting that the thymic involvement was the same in each type of tolerance. These results suggest that the preferential disappearance of the CD4(+)-V beta 6+ T cells (of host origin) and the effector T cells of GVHD (of donor origin) occurred only in the periphery of the C3H mice tolerized with AKR spleen cells plus CP and was attributable to the destruction of Ag-stimulated T cells by the CP treatment. In contrast, the intrathymic clonal deletion of immature V beta 6+ T cells was a common mechanism for both of the tolerance induction systems.

Animals↗
PubMed1991

[Immunohistochemical study of fibronectin expression in cancer tissue before and after irradiation].

We examined the expression and distribution of fibronectin in cancer tissues from 19 patients with cancer of the head and neck regions. Samples taken before and after irradiation with approximately 10 Gy and 20 Gy or 30 Gy were immunohistochemically stained by the avidin-biotin-horseradish peroxidase method using a monoclonal antibody against human fibronectin. No remarkable changes in the expression or distribution pattern of fibronectin were found between tissue specimens taken before and after each dose of irradiation. The prognosis, however, differed according to the pattern of fibronectin distribution. Eight patients in whom the cancer tissue was thickly encircled by fibronectin are alive without local recurrence or distant metastasis. Meanwhile, six patients in whom fibronectin was expressed faintly or focally (or scattered) in the cancer tissue died or developed recurrence soon after treatment. These findings indicate that the immunohistochemical analysis of fibronectin in cancer tissue exposed to irradiation may be applicable as a predictive assay in radiotherapy of cancer.

Adult↗
PubMed1991

Recombinant human granulocyte colony-stimulating factor improves the compromised state of recipient mice without affecting the induction of specific tolerance in the cyclophosphamide-induced tolerance system.

The effects of recombinant human granulocyte CSF (rhG-CSF) on cyclophosphamide (CP)-induced tolerance was studied. In the recipient C57BL/10 Sn Slc (B10) mice given 1 x 10(8) B10.BR Sg Sn Slc (B10.BR) spleen cells (SC) on day -2 followed by 200 mg/kg CP on day 0, the number of leukocytes and neutrophils in the periphery declined to their minimum levels on day 4. When rhG-CSF in a dose of 200 micrograms/kg was given daily for 5 days to the B10 mice, which had been treated with B10.BR SC and CP, starting one day after the administration of CP, the leukocyte and neutrophil counts declined to the same levels as those in the B10 mice treated with B10.BR SC and CP alone on day 2. On day 4, however, the counts recovered to their normal levels. The nucleated cell count of the spleen in the B10 mice given B10.BR SC and CP followed by rhG-CSF decreased less and recovered faster than that in the B10 mice given B10.BR SC and CP. The case was found to be the same in bone marrow, and the difference did not reach statistical significance. When the recipient mice were inoculated i.p. with 4 x 10(4) Pseudomonas aeruginosa (GNB-139) on day 4, the survival of the B10 mice treated with B10.BR SC and CP was markedly improved by rhG-CSF administration. The administration of rhG-CSF did not affect either the prolongation or the specificity of skin allograft survival, as shown in an H-2 mis-matched combination of B10.BR----B10 and in an H-2 identical combination of AKR/J Sea(AKR)----C3H/HeN Crj (C3H). The tolerant state, which was demonstrated by various immune responses, such as CTL, delayed footpad reaction, and antibody, was also not affected by rhG-CSF. Furthermore, the basic mechanisms for inducing a long-lasting skin allograft tolerance in this system--namely, the specific destruction of Ag-stimulated and then proliferating mature T cells in the periphery, the establishment of mixed chimerism, and the intrathymic clonal deletion of immature T cells--were preserved even when rhG-CSF was given to C3H mice previously made tolerant of AKR.

Animals↗
PubMed1991

Apolipoprotein A-I deficiency due to a codon 84 nonsense mutation of the apolipoprotein A-I gene.

The molecular genetic defect of a female patient with apolipoprotein A-I (apoA-I) deficiency and premature atherosclerosis was examined. Her parents were first cousins. Her plasma density fraction from 1.063 to 1.21 g/ml contained no apoA-I on SDS/PAGE and no measurable high density lipoprotein cholesterol. Southern blot hybridization showed no gross abnormality to be present in the patient's apoA-I gene and homozygosity for a haplotype of restriction fragment length polymorphisms in the apoA-I gene region. Sequencing after amplification by PCR revealed a codon 84 nonsense mutation (CAG----TAG, Gln----stop) of exon 4 and a codon 67 missense mutation (GCC----ACC, Ala----Thr) of exon 3 in the patient's apoA-I gene. The data from dot-blot hybridization with allele-specific oligonucleotide probes indicated that she was homozygous for the apoA-I gene with regard to the two mutations. The codon 37 missense mutation was also detected in the apoA-I gene of 6 out of 60 controls, who all had normal levels of apoA-I and high density lipoprotein cholesterol, suggesting that the missense mutation is polymorphic and not associated with apoA-I deficiency. These findings indicate that homozygosity for the apoA-I gene with codon 84 nonsense mutation causes the deficiency of apoA-I and of high density lipoprotein cholesterol in the patient.

Adult↗
PubMed1991

Specific destruction of host-reactive mature T cells of donor origin prevents graft-versus-host disease in cyclophosphamide-induced tolerant mice.

In cyclophosphamide (CP)-induced tolerance, a long lasting skin allograft tolerance was established in many H-2-identical strain combinations without graft vs host disease. Destruction of donor-reactive T cells of host origin, followed by intrathymic clonal deletion of these cells, has been revealed to be the chief mechanisms of this system. Here, we studied the fate of host-reactive populations in donor-derived T cells of C3H/He (C3H) (H-2k, Mls-1b, Mls-2a) mice rendered CP-induced tolerant to AKR/J (AKR) (H-2k, Mls-1a, Mls-2b), by assessing AKR-derived Thy-1.1+ T cells bearing TCR V beta 3 that are specifically reactive with Mls-2a-encoded Ag of the recipient C3H mice. In the AKR-derived Thy-1.1+ lymph node cells of the C3H mice that had been treated with AKR spleen cells plus CP, CD4(+)-V beta 3+ T cells were obviously decreased by day 10 after the CP treatment. At this stage, the Thy-1.1+ T cells were not detected in the C3H thymus, suggesting that the obvious decrease of CD4(+)-V beta 3+ T cells of AKR origin was not due to intrathymic clonal deletion in the recipient C3H mice. Therefore, the destruction of the host-reactive mature T cells of donor origin, as well as that of the donor-reactive mature T cells of host origin, occurred by the CP treatment at the induction phase. Furthermore, after the establishment of intrathymic mixed chimerism in the recipient C3H mice, V beta 3+ T cells were not detected among the Thy-1.1+ T cells of AKR origin in the mixed chimeric thymus, suggesting that the host-reactive immature T cells repopulated from the injected donor hematopoietic cells were clonally deleted in the recipient thymus. These two mechanisms appear to prevent graft vs host disease in CP-induced tolerance.

Animals↗
PubMed1991

Effects of sublingual nitroglycerin in patients receiving transdermal nitroglycerin for coronary artery disease: prevention of cross-tolerance.

The systemic hemodynamic and coronary dilative responses to sublingual nitroglycerin were studied in patients receiving transdermal nitroglycerin. A total of 48 patients with coronary artery disease were divided into 4 groups: 12 patients receiving 1 tablet of sublingual nitroglycerin without transdermal nitroglycerin (Group 1), 12 patients receiving 1 tablet of sublingual nitroglycerin with 12-hour-daily intermittent therapy of transdermal nitroglycerin (Group 2), 12 patients receiving 1 tablet of sublingual nitroglycerin with continuous therapy of transdermal nitroglycerin with continuous therapy of transdermal nitroglycerin (Group 3), and 12 patients receiving 2 tablets of sublingual nitroglycerin with continuous therapy of transdermal nitroglycerin (Group 4). Before and during administration of sublingual nitroglycerin, aortic pressure, left ventricular pressure, and coronary artery diameter were examined at diagnostic cardiac catheterization in all patients. During sublingual nitroglycerin, the decreases of aortic systolic pressure and left ventricular end-diastolic pressure were greater in Group 1, 2, and 4 than in Group 3. Dilation of coronary arteries by sublingual nitroglycerin tended to be greater in Group 1, 2, and 4 than in Group 3. Thus, the effects of sublingual nitroglycerin for the relief of ischemia might be more prominent in patients with intermittent therapy of transdermal nitroglycerin than in those with continuous therapy. The increased dose of sublingual nitroglycerin for the relief of ischemia might be more effective in patients with continuous therapy of transdermal nitroglycerin.

Administration, Cutaneous↗
PubMed1991

Serotonin-containing epithelial cells in rat duodenum. I. Quantitative morphometric study of the distribution density.

Serotonin (5HT)-containing epithelial cells in rat duodenum were studied quantitatively by three-dimensional morphometric analysis. Longitudinal sections covering the whole length of rat duodenum were stained by either 5HT immunohistochemistry or by glyoxylic acid fluorescent histochemistry. Three-dimensional values for positive cell density, namely the number of 5HT cells per unit volume of the epithelium, were obtained by stereological morphometry with the aid of a computer-assisted image analyzer. This analytical method provides an absolute value for the distribution density of 5HT-containing cells regardless of thickness of sections, or which of the two histochemical procedures is used. The mean number of such cells per unit volume was higher in the crypts than in the villi but varied little along the duodenum. The density of 5HT cells in a given duodenal region, however, varied greatly among individual animals. The villi of the 10 to 16-mm segment from the pylorus were identified as having the smallest individual variation and therefore as being the most suitable for statistical evaluation in future pharmacohistochemical investigations.

Animals↗
PubMed1991

Serotonin-containing epithelial cells in rat duodenum. II. Quantitative study of the effect of 5HTP administration.

The effect of 5-hydroxytryptophan (5HTP) administration on serotonin (5HT)-containing epithelial cells in rat duodenum was investigated quantitatively using three-dimensional morphometry to determine cell density and HPLC to measure 5HT and 5HTP concentrations. The results are interpreted in terms of the amine precursor uptake and decarboxylation (APUD) capacity of the cells. After administration of 5HTP, no significant change was observed in the density of 5HT-fluorescent epithelial cells in the duodenal region examined. Moreover, no evidence could be obtained that the concentration of 5HT in duodenal villi was increased after 5HTP administration, despite a highly significant increase in serum 5HTP and 5HT levels. These results indicate that no cells in the duodenal epithelium have the ability to decarboxylate exogenously administered 5HTP and convert it to 5HT under physiological conditions.

5-Hydroxytryptophan↗
PubMed1991

A cytogenetic survey of 14,835 consecutive liveborns.

The results of chromosome studies on cultured umbilical cord blood lymphocytes from a consecutive series of 14,835 liveborn infants (7,608 males and 7,227 females) are described. Ninety-three infants (6.27 per 1,000) had a major chromosome abnormality. Of these, thirty-one infants (2.09 per 1,000) had sex chromosome abnormalities. Seven male infants had a 47,XXY karyotype, five had a 47,XYY karyotype, and three were mosaics. One male had a ring Y chromosome in all cells examined. A pericentric inversion of the Y chromosome was found in one case. Seven female infants had a 47,XXX karyotype, one had a 45,X karyotype and six were mosaics. Sixty-two infants (4.18 per 1,000) had autosomal abnormalities. There were twenty-one infants with trisomy 21 including one mosaic, six infants with trisomy 18, and two infants with trisomy 13 of a Robertsonian translocation type. Three infants had an unbalanced derivative chromosome resulting from a parental reciprocal translocation. Two infants with a partial monosomy of chromosome 13 were detected. There were four infants carrying an additional small marker chromosome. Twenty-four infants (1.62 per 1,000) had a balanced structural rearrangement of the autosomes; eleven with a Robertsonian translocation, eleven with a reciprocal translocation, and two with a pericentric inversion. The incidence of each type of major chromosome abnormality in this study was quite similar to that obtained from previous newborn surveys.

Chromosome Aberrations↗
PubMed1991

Isolation of a full-length cDNA encoding mouse aromatase P450.

A full-length cDNA clone for aromatase P450 has been isolated from a pregnant mouse ovarian cDNA library. The insert of this clone (2394 bp) contains a 1509-bp open reading frame encoding 503 amino acid residues together with a 46-bp 5'-untranslated stretch and an 839-bp 3'-untranslated region to which a poly(A) tract is attached. Northern blot analysis of ovarian RNA from pregnant mice reveals a major mRNA band of 2.5 kb with a minor band of 2.1 kb. Comparison of mouse aromatase P450 with that of rat, human, and chicken shows 91, 81, and 69% identity in the nucleotide sequence and 92, 79, and 69% identity in the deduced amino acid sequence, respectively. The membrane-spanning domain of mouse aromatase P450 is estimated to be an extremely hydrophobic segment located within the N-terminal region of the molecule. Furthermore, a highly conserved heme-binding domain is noticed.

Amino Acid Sequence↗
PubMed1991

Responses of calcitonin gene-related peptide-immunopositive nerve fibres in the periodontal ligament of rat molars to experimental tooth movement.

Nerve fibres showing CGRP-immunoreactivity were exclusively distributed around blood vessels in the periodontal ligament of normal teeth. The CGRP-positive nerves as well as the vessels were more dense during tooth movement and reached a maximum density and intensity of immunoreaction after 3 days. After that, the immunoreactive nerves gradually disappeared, and returned to the control level by the 7th day. Some of the CGRP-nerves were adjacent to bone resorptive lacunae at 3 days when active remodelling of alveolar bone was taking place. These findings suggest that the distribution of CGRP-positive nerves is dynamically changed around the blood vessels in the periodontal ligament during tooth movement, and that CGRP might affect the regulation of blood flow in the ligament. CGRP is possibly involved in the tissue remodelling, directly or indirectly, in addition to its function as a neurotransmitter.

Animals↗
PubMed1991

Parasympathetic innervation of cutaneous blood vessels examined by retrograde tracing in the rat lower lip.

The origin of vasoactive intestinal polypeptide (VIP)-immunoreactive and acetylcholinesterase (AChE)-positive perivascular nerve fibers in the lower lip of rats was investigated using the retrograde tracer, wheat germ agglutinin conjugated to enzymatically inactive horseradish peroxidase gold complex (WGAapoHRP-Au), in combination with immunohistochemistry and enzyme histochemistry, by comparing the cells of origin of projection to the parotid gland. After the application of the tracer to the lip, small- to medium-sized nerve cells were labelled exclusively in the ipsilateral otic ganglion. Most of them showed moderate VIP-immunoreactivity and AChE activity. In contrast, injection into the parotid gland resulted in labelling of mostly large-sized cells of the otic ganglion which showed intense VIP-immunoreactivity and AChE activity. These results confirmed that the parasympathetic innervation of the rat lip originates from the otic ganglion. It was further suggested that there are at least two subpopulations in the otic ganglion cells, different from each other in size and in VIP-immunoreactivity, which separately innervate the salivary gland and the blood vessels.

Acetylcholinesterase↗
PubMed1991

Structure and expression of rat S-100 beta subunit gene.

The gene structure for S-100 beta subunit has been elucidated. The gene spans about 8 kbp and consists of 3 exons and 2 introns. The transcription initiation site was determined by an S1 nuclease mapping. The promoter region contains TATA-box-like and CAAT-box-like sequences. To examine the activity of the promoter sequence, a transfection of pS100 beta-lacZ fused gene to the cultured cells was carried out. C6 glioma cells showed a positive expression of beta-galactosidase. Gene-deletion experiments suggested the functional importance of the DNA fragment (22 bp) containing TATA-box-like and CAAT-box-like sequences. A factor protein that binds to the 100 bp DNA fragment containing the promoter sequence was specifically detected in the rat brain nuclear extract.

Animals↗
PubMed1991

Distribution of type B monoamine oxidase immunoreactivity in the cat brain with reference to enzyme histochemistry.

We studied the detailed distributions and morphology of structures immunoreactive to type B monoamine oxidase, and compared them with those stained by monoamine oxidase enzyme histochemistry in the brain of cats treated with or without colchicine. By means of the indirect immunohistochemical method in conjunction with type B monoamine oxidase monoclonal antibody, we demonstrated type B monoamine oxidase immunoreactivity in neuronal cell bodies, fibers and astroglial cells in the cat brain. As expected, the distribution of type B monoamine oxidase-immunoreactive cell bodies overlapped that of serotonin-containing ones in the lower brainstem and midbrain, as well as that of histaminergic ones in the posterior hypothalamus. We found novel cell groups containing type B monoamine oxidase in the areas described below. Intense type B monoamine oxidase-immunopositive and enzymatically active neurons, corresponding to liquor-contact ones, were discovered in the wall of the central canal of the spinomedullary junction. Weak immunoreactivity was identified in neurons of the dorsal motor nucleus of the vagus, parvocellular reticular formation and locus coeruleus complex, which have been reported to contain type A monoamine oxidase enzymatic activity. Type B monoamine oxidase-immunostaining in these structures was enhanced by treatment with colchicine. In addition, lightly immunostained cells were distinguished in the caudal portion of the hypothalamic arcuate nucleus, area of tuber cinereum, retrochiasmatic area, and rostral portion of the paraventricular thalamic nucleus after colchicine treatment. These cells also displayed monoamine oxidase activity; however, it was difficult to enzymatically characterize their nature due to its weak activity and sensitivity to inhibitors of both A and B. Distinct type B monoamine oxidase-immunoreactive fibers and terminal-like dots were abundant in the whole brain, particularly in the central gray, dorsal pontine tegmentum, interpeduncular and pontine nuclei, nucleus of the solitary tract and dorsal motor nucleus of vagus, where dense innervations of serotonergic fibers have been reported. Their immunoreactive density increased after colchicine treatment, but monoamine oxidase enzymatic reaction did not. An intense immunoreactivity could be seen in many glial cells in parts of the brain including myelinated axon pathways. The densest accumulation of such labeled glial cells was found in the central gray, inferior olive, medial geniculate body, substantia nigra, ventral tegmental area of Tsai, retrorubral area, hypothalamus, thalamus and bed nucleus of the stria terminalis. In contrast, the striatum contained less numerous type B monoamine oxidase-immunoreactive and enzymatically active astroglial cells in comparison with the other structures.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗