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T Maeda

Publications and source records attributed to T Maeda.

At least 883 records · Page 49Linked to original sources
PubMed1991

Investigations of origins of serotonergic projection to developing rat visual cortex: a combined retrograde tracing and immunohistochemical study.

The present study investigated whether the raphe neurons which give rise to the transient serotonergic fibers in the visual cortex of neonatal rats persist or disappear as the rats mature. Three experiments were performed employing the WGA-apoHRP-Au retrograde transport technique in conjunction with 5-HT or WGA-HRP immunohistochemical staining. WGA-apoHRP-Au was injected into the primary visual cortex of all rats 9 days postnatally. In the first experiment, the animals were examined after 2 days; retrogradely labeled cells were observed in the dorsal raphe nucleus (DR), the median raphe nucleus (MR), and in the B9 and B6 cell groups; the majority (82.5%) of the cells was serotonergic. In the second experiment, the examinations took place following a survival time of 8 weeks: virtually all of the original raphe-visual cortical serotonergic neurons were found to the present. In the third experiment, also performed after 8 weeks relabeling the raphe-visual cortical neurons by WGA-HRP, it was found that 37.2% of the raphe neurons which had projected to the neonatal visual cortex no longer possessed such projections.

Aging↗
PubMed1991

Monoaminergic interaction in the central nervous system: a morphological analysis in the locus coeruleus of the rat.

The locus coeruleus of the rat is richly innervated by many aminergic neurons varying in amine content and in site of origin. There are adrenergic and noradrenergic neurons originating in the medulla oblongata, dopaminergic from the hypothalamus, serotonergic from the mesencephalon and also intrinsic noradrenergic neurons in the locus coeruleus complex. Of these, adrenergic and dopaminergic inputs appear relatively specific and powerful.

Animals↗
PubMed1991

Detection and quantitative estimation of metalloporphyrins in vivo.

Spectrofluorometry, radioisotope (RI) labelling and high performance liquid chromatography (HPLC) can be used to estimate photosensitizer concentrations. The biodistribution of porphyrins and metalloporphyrins containing the bifunctional chelating agent diethylenetriamine pentaacetic acid (DTPA) was examined in tumour-bearing mice by nitrogen-pulsed laser spectrofluorometry (PLS) and RI labelling. The biodistribution of metalloporphyrin amino acid derivatives containing alkoxyl groups was also examined by PLS and HPLC analysis using an acetone powder extraction method. Spectrofluorometry is useful for estimating the biodistribution of porphyrins in tumour, lung, kidney and serum, but not in liver. However, spectrofluorometry cannot be used to evaluate the concentration of certain metalloporphyrins such as manganese complexes. The concentrations of porphyrins in liver measured by PLS and two other methods showed remarkable differences. RI labelling and HPLC analysis are obviously tedious methods. Therefore it seems practical to screen for a number of compounds using the spectrofluorometric method (PLS). Subsequently, the porphyrins which give good results with PLS should be measured using RI labelling and HPLC.

Animals↗
PubMed1991

Formation of liquid crystalline phase of actin filament solutions and its dependence on filament length as studied by optical birefringence.

We studied the formation and structure of liquid crystalline phase of F-actin solutions by polarized light photometry, assuming that a small domain of the liquid crystalline phase works as a linear retardation plate. Transmittance of polarized light due to the birefringence of liquid crystalline phase appeared above a threshold concentration of F-actin. The threshold increased with a decrease in filament length, which was regulated by calcium-activated gelsolin. The intensity increased linearly with increasing concentrations until it reached a stationary value. The deviation of optical axis direction of the putative retardation plate was estimated 7-15 degrees. These results indicate that:(a) the liquid crystalline phase is formed above a threshold concentration of F-actin; (b) the threshold is proportional to the inverse of filament length; (c) the ordered phase coexists with the isotropic one, increasing the volume fraction with increasing concentrations until all filaments take the liquid crystalline structure; (d) the filaments in liquid crystalline phase take a highly ordered array. These results can be attributed to the excluded volume effect of rod-like molecules on the formation of liquid crystalline structure.

Actin Cytoskeleton↗
PubMed1991

Evidence for a neural source of acute accumulation of serotonin in platelets in the injured spinal cord of rats. An experimental study using 5,6-dihydroxytryptamine treatment.

It was found previously that large numbers of platelets showing high serotonin (5-hydroxytryptamine; 5-HT) immunoreactivity appeared in hemostatic plugs at the traumatized cord segment in the acute phase of a trauma. In order to determine the origin of 5-HT in the platelets, we investigated the 5-HT immunoreactivity of platelets accumulating in hemostatic plugs at the traumatized spinal cord segment at 5 minutes after injury. This investigation was carried out by light and electron microscopic immunohistochemistry in rat spinal cord pretreated with 5,6-dihydroxytryptamine (5,6-DHT). The hemorrhagic lesion formed at the neural 5-HT-depleted spinal cord segment was completely 5-HT immunonegative, while platelets in lesions in cord segments of control animals or rostral to the injection site of 5,6-DHT in experimental animals where neural 5-HT was not depleted were 5-HT immunoreactive. The results strongly suggest that a significant amount of 5-HT is released from neural elements at the injury site and is transiently incorporated into the platelets in situ.

5,6-Dihydroxytryptamine↗
PubMed1991

Artificial cell adhesive proteins engineered by grafting the Arg-Gly-Asp cell recognition signal: factors modulating the cell adhesive activity of the grafted signal.

An artificial cell adhesive protein could be engineered by grafting the RGDS tetrapeptide, the core sequence of the major cell adhesive site of fibronectin, to a truncated form of Staphylococcal protein A (tSPA) via cassette mutagenesis of the tSPA expression vector pRIT2T [T. Maeda et al. (1989) J. Biol. Chem. 264, 15165-15168]. We synthesized a panel of tSPA derivatives grafted with various RGDS-containing oligopeptides to address the problem of how the cell adhesive activity of the resulting tSPA derivatives was affected by the length and amino acid sequence of the grafted oligopeptides and by the sites on tSPA where the extra oligopeptides were inserted. The results showed that (i) the amino acid residues flanking the RGDS core sequence played a key role in modulating the cell adhesive activity of the grafted RGDS signal; (ii) at least two sites on tSPA, each corresponding to on e of the two HindIII sites of pRIT2T, were competent in sustaining the cell adhesive activity of the grafted signal; and (iii) the divalent tSPA containing the RGDS signal at both sites was more active than monovalent derivatives containing only one signal at either site. These results provide a strategic basis for engineering of artificial cell adhesive proteins by grafting the RGDS signal.

Amino Acid Sequence↗
PubMed1991

Schizosaccharomyces pombe ste11+ encodes a transcription factor with an HMG motif that is a critical regulator of sexual development.

Schizosaccharomyces pombe ste11 encodes a member of the family of HMG-box proteins. Its transcript is induced in response to nitrogen starvation and a concomitant decrease of the intracellular cAMP level. Expression of ste11 is essential for induction of sexual development, and its ectopic expression stimulates uncontrolled mating and sporulation. Ste11 protein regulates positively transcription of the following genes required for sexual development: the mating type genes, matP and matM, and the mei2 gene, which is essential for commitment to meiosis. Ste11 protein synthesized in vitro binds specifically to a DNA fragment carrying a 10-base motif TTCTTTGTTY that is an essential cis-acting element for the induction of mei2 and is commonly seen in the upstream regions of the genes inducible by nitrogen starvation. These observations strongly suggest that Ste11 serves as a key transcription factor for sexual development.

Amino Acid Sequence↗
PubMed1991

An electron microscopic study of experimentally-induced comedo and effects of vitamin A acid on comedo formation.

The mechanisms of comedogenesis and comedolysis were investigated at the ultrastructural level after applying oleic acid (OA) only, or oleic acid together with vitamin A acid (VAA), to rabbit ears daily for two weeks. 1) In the follicular epithelium of the experimentally-induced comedo (EIC) by OA, several ultrastructural changes similar to those in human comedo were observed. EIC in rabbit ears appeared to be induced both by the hyperkeratinization of the follicular epithelium and by the delayed desquamation of horny cells due to the persistence of intercellular binding apparatus. 2) VAA strongly inhibited the formation of EIC. In the follicular epithelium, two different types of changes, non-cohesive hyperkeratinization and inhibition of keratinization, were observed. These represent the cell injury and recovery stages, respectively. VAA induced the disturbance of follicular epithelial keratinization and reduction of intercellular bindings between horny cells. These effects might prevent the cohesion and accumulation of horny cells and inhibit EIC formation. 3) The number of Odland bodies (Ods) showed an inverse correlation with the cohesion of horny layer. These findings support the theory that Ods have a desquamating function as extracellular lysosomes. The change in Ods would also contribute to both EIC formation by OA and the inhibition by VAA. In addition, VAA caused a characteristic increase in Ods with lamellar structures. It is suggested that Ods with lamellar structures have a desquamating function.

Acne Vulgaris↗
PubMed1991

A biliary protein identified by immunoblotting stimulates proliferation of peripheral blood T lymphocytes in primary biliary cirrhosis.

The source of activation of T lymphocytes in primary biliary cirrhosis (PBC) is undefined. Hence, T-cell-mediated reactivity against a biliary tract antigenic protein from human bile was studied. The bile protein was fractionated by 30-50% saturated ammonium sulphate and gel-chromatography, and analysed by SDS-PAGE and Western immunoblotting using rabbit antisera to the bile protein. The antisera reacted specifically with human bile duct epithelium. Western blotting of bile proteins showed two major bands, the B1 and B2 antigens. B1 stained for sialoglycoprotein but not lipid, but B2 was negative for both. Cell-mediated reactivity was tested by proliferation of peripheral lymphocytes against B1. Taking the upper limit of the normal range for stimulation indices (S.I.) as less than 1.89 (= mean + 2 SD), a mitogenic response was detected in 14 of 16 patients with PBC (S.I.: 11.7 to 2.3), and in 4 of 15 patients with chronic active hepatitis, but in none of 12 patients with drug-induced intrahepatic cholestasis or obstructive jaundice. The B2 protein was non-stimulatory. Lymphocyte proliferation to B1 in PBC was confined to T cell fractions of peripheral blood leucocytes. There was no cross-antigenicity between B1 and the M2 antigens, according to Western blotting using the rabbit antisera and PBC sera with anti-M2 reactivity. Thus, the B1 biliary protein is a possible source of T cell activation in PBC and hence could be an immunological co-factor in the pathogenesis of this disease.

Aged↗
PubMed1991

Dilated posterior superior pancreaticoduodenal vein: recognition with CT and clinical significance in patients with pancreaticobiliary carcinomas.

The authors retrospectively reviewed computed tomographic (CT) scans, angiograms, and surgical-pathologic records of 226 patients without and 64 patients with pathologically proved pancreaticobiliary carcinoma to evaluate frequency of depiction, normal range of size, and causes of dilatation of the posterior superior pancreaticoduodenal vein (PSPDV) at CT. Among the patients with pancreaticobiliary carcinoma, CT demonstrated enlarged PSPDVs (diameter, greater than or equal to 8 mm) in seven patients. CT and angiography showed that the portal-superior mesenteric vein (P-SMV) was occluded or stenotic at its confluence in three patients and was normal in four patients. Among the latter four patients, localized tumor invasion was found surgically-pathologically along the right lateral wall of the P-SMV in three. A dilated PSPDV with obliteration of the P-SMV at CT may confirm tumor extension to the P-SMV. In patients with a normal P-SMV at CT, a dilated PSPDV indicates that the tumor has extended beyond the pancreatic parenchyman and occluded other pancreaticoduodenal veins or extended to the wall of the P-SMV.

Aged↗
PubMed1991

[Synthesis and antifungal activity of butenafine hydrochloride (KP-363), a new benzylamine antifungal agent].

In screening of new antifungal agents, bis(naphthalenemethyl)amines were found to have more potent antifungal activity than clotrimazole. Studies on their structure-activity relationships indicated that benzylamines had potent antifungal activity. Among them, butenafine hydrochloride (N-p-tert-butylbenzyl-N-methyl-1-naphthalenemethylamine hydrochloride, KP-363) has proved to show the strongest activity. It exhibits a wide spectrum activity in vitro against particularly dermatophytes (87 strains; minimal inhibitory concentration (MIC) range, 0.0015 to 0.05 microgram/ml), and also against Aspergillus (15 strains; MIC range, 0.025 to 0.78 microgram/ml), Cryptococcus neoformans (4 strains; MICs 0.78 and 1.56 micrograms/ml) and yeasts of genus Candida (67 strains; MIC range, 3.13 to greater than 100 micrograms/ml).

Animals↗
PubMed1991

Characteristics of blood flow velocity patterns of central systemic veins in healthy adults assessed by Doppler echocardiography.

To evaluate the differences in shape and phase lag of the flow velocity curves in the superior (SVC) and inferior (IVC) venae cavae and the hepatic vein (HV), Doppler echocardiographic examination was performed in 40 healthy adults (aged 20 to 67 years, mean +/- SD: 39 +/- 12 years). Flow velocity patterns in each vein were characterized by 4 major deflections: S wave, a systolic forward flow; D wave, a diastolic forward flow; A wave, a small backward flow or reduction of diastolic forward flow due to atrial contraction; and O wave, a small backward flow or reduction of forward flow after the second heart sound. Except for a reduced phasic flow in a collapsed IVC, the venous flow velocity recordings in each vein demonstrated very similar pulsatile patterns and small differences in mean time lags of less than 50 msec. In general, the lowest values of peak A/peak S, peak O/peak S and peak D/peak S were observed in HV flow and the highest in IVC flow. Backflows of A and O waves were prominent in HV flow, but small and least frequent in IVC flow. These data suggest that the baseline of the central venous flow recordings might shift downward in HV flow and upward in IVC flow. However, even if both the baseline shift and amplitude of the flow curve were normalized in each venous flow velocity curve, apparent differences in shape of the flow velocity curves would remain. We concluded that the characteristics and differences of each central venous flow velocity pattern should be noted in studies of these areas.

Adult↗
PubMed1991

Immunohistochemical localization of laminin in the periodontal Ruffini endings of rat incisors: a possible function of terminal Schwann cells.

Ruffini endings in the periodontal ligament of rodents are ensheathed by a special type of terminal Schwann cell with a particularly developed rough endoplasmic reticulum and Golgi apparatus, and further enveloped by a characteristic multi-layered structure. In order to reveal the functional significance of the structures, localization of a laminin molecule in the periodontal Ruffini endings of rats was immunohistochemically investigated at the levels of light and electron microscopy. Immunostaining using an anti-laminin serum clearly demonstrated the profiles of the Ruffini endings as well as those of the blood vessels. Ultrastructurally, reaction products for laminin were deposited in the entire thickness of the multi-layered structure, supporting the idea that this structure is derived from the basal lamina. The basal lamina, immunoreacting with laminin antiserum, was penetrated by periodontal collagen fibers, possibly serving as an adhesive device between the Ruffini endings and surrounding collagen fibers. The laminin immunoreactive materials were also recognized in the vesicles and caveolae of the terminal Schwann cells which tended to gather at the interstitial surface of the cells. The terminal Schwann cells are therefore believed to be directly involved in the formation of the multilayered basal lamina through the active production of its materials.

Animals↗
PubMed1991

[Clinico-histological study of low-density non-enhancing glioma].

Some gliomas are not noticeably enhanced on initial computer tomography (CT) scans. Such low-density non-enhancing gliomas have a relatively long period between onset and surgery ranging from 5 to 25 months. The mechanism causing the low density over a certain period of time in the sequential CT findings was retrospectively investigated. Characteristic histological findings associated with such low-density areas were microcystic formation, necrosis, intratumoral edema, infiltrative growth, and absence of capillary proliferation. Proliferation of capillary vessels is characteristic of CT enhancement.

Adolescent↗
PubMed1991

T-lymphocyte-receptor repertoire of infiltrating T lymphocytes into NOD mouse pancreas.

This study analyzed T-lymphocyte-receptor V beta genes of infiltrating lymphocytes into the pancreases of 12- to 16-wk-old NOD mice with severe insulitis and 5-wk-old mice with mild insulitis by the quantitative polymerase chain reaction method. The V beta transcripts on infiltrating T lymphocytes into pancreases with severe insulitis in older NOD mice were diverse. In contrast, the V beta 11 gene transcript was predominantly expressed on T lymphocytes in the pancreas in younger NOD mice with mild insulitis, suggesting the possible role of V beta 11+ T lymphocytes in triggering insulitis in this species.

Animals↗
PubMed1991

Specific 125I-endothelin-1 binding sites in the central nervous system.

The quantitative receptor autoradiographic method we used revealed that specific 125I-endothelin-1 (125I-ET-1) binding sites are highly concentrated in the choroid plexus (ChP), subfornical organ (SFO), lacunosum molecular layer of the hippocampus (LMol) and granular layer of the cerebellum (GC) of the rat brain. High densities of the binding sites were also observed in the laminae I-III and intermediolateral nucleus of the porcine spinal cord. 125I-ET-1 bound to the rat ChP and LMol with a high-affinity and to the SFO and GC with a low-affinity. The possibility that ET-1 acts as a neuropeptide within the central nervous system by interacting with specific receptors would have to be considered.

Animals↗
PubMed1991

Brain natriuretic peptide binding sites in rat kidney.

Specific binding sites for [125I] porcine brain natriuretic peptide-26 ([125I]BNP-26) were investigated in the rat kidney by using receptor autoradiographic and membrane binding techniques. The binding sites were discretely localized in the glomeruli and inner medulla. There were no differences between the localization of [125I] BNP-26 and [125I] alpha-rat ANP binding sites. [125I]BNP-26 binding to solubilized membranes from isolated glomeruli of the rat kidney was saturable, and a single class of high-affinity sites. [125I]BNP-26 bound to two sites in solubilized inner medullary membranes. The rank order of potency to inhibit binding was BNP-26 = alpha-rat ANP (1-28) greater than atriopeptin III [ANP-(103-126)] much greater than atriopeptin I [ANP(103-123)] greater than des-Cys105, Cys121-ANP-(104-126). The possibility that BNP-26 regulates, as a circulating hormone, kidney functions by binding to ANP receptors would have to be considered.

Animals↗