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Biomedical subjects

N Mizuno

Publications and source records attributed to N Mizuno.

At least 271 records · Page 15Linked to original sources
PubMed1990

Infrahyoid and accessory motoneurons in the Japanese monkey (Macaca fuscata).

The segmental and topographical organization of motoneurons innervating the infrahyoid (IH) and the spinal accessory (AC) muscles was studied in the Japanese monkey (Macaca fuscata) with the retrograde horseradish peroxidase (HRP) method after application of HRP to the peripheral nerve branches supplying the IH and AC muscles. IH motoneurons constitute two distinct slender cell columns, a longer medial and a shorter lateral one. The medial cell column extends from the most caudal level of the hypoglossal nucleus to the lower levels of the second cervical (C2) cord segment. In the medial column, motoneurons supplying the sternohyoid and sternothyroid muscles are distributed at the medullary and C1 levels, while those innervating the omohyoid muscle are primarily distributed at the C2 level. The lateral cell column consists of motoneurons supplying the thyrohyoid muscle and extends from the most caudal level of the hypoglossal nucleus to the middle levels of the C1 cord segment. Axons of thyrohyoid motoneurons follow a dorsomedially directed bent emergent course, making a hairpin turn. AC motoneurons supplying the sternocleidomastoid (SC) and trapezius (TZ) muscles form a single slender cell column extending from the most rostral level of the pyramidal decussation to the middle levels of the C6 cord segment. SC motoneurons are distributed from the most rostral level of the pyramidal decussation to the middle levels of the C3 cord segment, while TZ motoneurons are distributed from the upper levels of the C2 cord segment to the lower levels of the C6 cord segment. At the levels of the C2 and C3 cord segments, both SC and TZ motoneurons are distributed in the AC cell column; the cluster of SC motoneurons is located dorsomedial to that of TZ motoneurons.

Animals↗
PubMed1990

Immunohistochemical demonstration of glutaminase in catecholaminergic and serotoninergic neurons of rat brain.

The presence of phosphate-activated glutaminase in monoaminergic neurons was shown in the rat brain by a double-staining method using a mouse monoclonal anti-glutaminase antibody combined with rabbit antisera against tyrosine hydroxylase, dopamine-beta-hydroxylase, phenylethanolamine-N-methyltransferase or serotonin. Glutaminase-like immunoreactivity was detected within perikarya of many monoaminergic neurons in the substantia nigra pars compacta, locus ceruleus, raphe nuclei, etc. Possible functional significance of glutaminase in monoamine neurons was discussed.

Animals↗
PubMed1990

Cell cycle analysis of human dermal fibroblasts cultured on or in hydrated type I collagen lattices.

The proliferation and cell cycle phase composition of human dermal fibroblasts cultured on or in type I collagen lattices (reconstituted dermis model) were examined. On collagen lattices, as compared with conventional cultures on plastic dishes, the proliferation of human dermal fibroblasts was suppressed, being arrested at about one-half the saturation density after 10 days of culture. In collagen lattices, proliferation was further suppressed, being nearly arrested within 4-7 days of culture. Cells were analyzed for cell cycle phases by two-color flow cytometry using DNA staining and S phase cell staining with FITC-conjugated antibromodeoxyuridine antibody. After 5 days of culture, the number of S phase cells on collagen lattices was 49.3% of that on plastic dishes, with an increase in G0G1 phase cells of 79.8%. In collagen lattices, the number of S phase cells was very small (4.3% of all cells), and most of the cells accumulated in G0G1 phase. These findings suggest that the cell cycle of fibroblasts is arrested at G0G1 phase by their interaction with collagen. On the basis of these results, the reconstituted dermis model using collagen lattice is considered to be analogous to the dermis in vivo with respect to cell growth and cell cycle phase composition.

Cell Cycle↗
PubMed1990

Enhanced melanogenesis of murine melanoma cells cultured on or in collagen gel.

To elucidate the interaction between melanoma and its matrix, we cultured B16 murine melanoma cells on and in type I collagen gel and evaluated specified functions of melanoma cells; tyrosinase activity and melanin-synthesizing capacity. Proliferation of cells cultured in these environments was markedly suppressed compared with that of cells cultured conventionally on plastic. On the other hand, the tyrosinase activity of cells cultured in or on collagen gel was two to three times higher than that of cells cultured on the plastics, while their melanin production was approximately double that achieved during conventional culture of cells. In conclusion, collagen gel influenced the growth and cell-specific functions of the melanoma cell. The culture system using collagen gel as substrate may be useful for the investigation of the interaction between melanoma and its matrix.

Animals↗
PubMed1990

Parallel arrangement, growth inhibition and cell cycle phase analysis of human dermal fibroblasts cultured in collagen lattice.

Human dermal fibroblasts were cultured in a hydrated type I collagen lattice. When collagen fibers were arranged in one direction, fibroblasts were arranged in the same direction. Cell proliferation was markedly suppressed in the collagen lattice as compared with that on plastic, with growth being arrested after day 5. No differences in proliferation were observed between aligned cells and randomly oriented cells. Flow cytometry with DNA staining was performed to analyze each phase of the cell cycle of fibroblasts. Among the 10,000 cell population, S phase cells on day 2 of culture accounted for 43% on plastic but were markedly inhibited to 25% in the lattice. On day 4, S phase cells accounted for 33% on plastic but only for 10% in the lattice. These findings suggest that cell advancement to the S phase is markedly inhibited in the collagen lattice, resulting in accumulation of most of cells in the G0G1 phase. The present study clearly showed that culture in the collagen lattice allowed alignment of fibroblasts with a definite orientation as observed in vivo and produced a status resembling that in vivo in terms of proliferation and cell cycle phase composition.

Adult↗
PubMed1990

Correlation of contractility and proliferative potential with the extent of differentiation in mouse fibroblastic cell lines cultured in collagen lattices.

Four types of fibroblastic cell lines at various stage of differentiation, which had been derived from syngeneic mice, were cultured in collagen lattices (reconstituted dermis model). Lattice contraction, growth in the lattice, and cell morphology were compared. The following cell lines were used: [I] precrisis cells within several subcultures derived from the skin of Balb/c mice, [II] an established normal cell line derived from syngeneic mice (Balb/3T3 clone A31), and [III] two transformed lines (Balb/3T12-3, 3T3-B-SV40) originating from [II]. The cells adopted a bipolar spindle form in the collagen lattice. Lattice contraction was the most marked with cell type [I] followed in order by [II] and [III]. Relative growth in the lattice occurred in the reverse order (III greater than II greater than I). These findings suggested a correlation between lattice contraction and growth in the lattice and also between the extent of differentiation and lattice contraction.

Animals↗
PubMed1990

Effects of human recombinant tumor necrosis factor-alpha (TNF-alpha) on the proliferative potential of human keratinocytes cultured in serum-free medium.

The effects of human recombinant tumor necrosis factor-alpha (TNF-alpha) on human keratinocytes cultured in a serum-free medium were investigated. TNF-alpha markedly suppressed cell growth. The growth-inhibitory effect was reversible and cytostatic at a concentration of 1-5 U/ml, but appeared to be irreversible and cytocidal at 10 U/ml. The growth suppressive effect was more marked when TNF-alpha was added in the late growth phase or preconfluent phase than when it was added in early or mid-growth phases. No effects of TNF-alpha on cell adhesion to the substrate were observed. These results indicate that TNF-alpha is a very potent anti-proliferative agent for human keratinocytes.

Cell Adhesion↗
PubMed1990

Infiltration of melanoma cells into the type I collagen gel.

Melanoma cells were cultured on type I collagen gel, and the infiltration of of those cells into the gel was observed. B16 murine melanoma cells initially adopted a spherical form on the gel, but they assumed a dendritic form after infiltration into the interior. The degree of infiltration increased very rapidly and was time-dependent. No correlations between the growth rate or melanogenic activity and infiltrative potential were observed. When Syrian hamster and human melanoma cell lines were cultured, the degrees of infiltration varied. This culture system using collagen gel is considered to be a useful in vitro model of tumor cell invasion.

Animals↗
PubMed1990

Nail abrasion: a new treatment for ingrown toe-nails.

A simple new method for the treatment of ingrown toe-nails was devised and applied to 33 toe-nails in 22 patients. The entire nail surface, except for the margin, was abraded until the nail became flexible with a Schreu's skin grinder equipped with a steel bar. When there was infection or granulation of the nail wall, the imbedded nail corner was trimmed before abrasion. The patients underwent additional treatments when one treatment was not enough to achieve cure or when discomfort appeared, which was the first symptom of recurrence. The average number and duration of treatments was 2.9 times and 16 months, respectively. Relief from pain occurred in all patients soon after abrasion was performed. Recurrence of infection and granulation was observed in only one patient. Five patients (23%) remained problem-free for more than one year without any additional treatment, because their incurved nail was gradually improved in shape by repetition of this procedure. This therapy was particularly effective in patients with severely incurved nails.

Adult↗
PubMed1990

Topical PUVA, etretinate, and combined PUVA and etretinate for palmoplantar pustulosis: comparison of therapeutic efficacy and the influences of tonsillar and dental focal infections.

Twenty patients with palmoplantar pustulosis (PPP) were treated with topical PUVA, oral etretinate (Re), or combined PUVA and etretinate (Re-PUVA). Re and Re-PUVA treated sites improved and/or cleared more rapidly than PUVA treated sites. Complete clearance was observed in six of ten sites treated with Re-PUVA, two of ten with Re, and one of ten sites with PUVA within 12 weeks. UVA-control sites failed to be cleared within 12 weeks. Remission periods after stopping the treatment were 1.5 +/- 0.5 weeks (n = 2) with Re, 10.5 +/- 11.4 weeks (n = 6) with Re-PUVA, and one year (n = 1) with PUVA. These results overall suggested that Re-PUVA is the most effective treatment for PPP. Tonsillar focal infection (TFI) and dental focal infection (DFI) were found in 6/20 and 17/20 patients, respectively. However, the presence of focal infection (FI), TFI and/or DFI, did not appear to interfere with the therapeutic activities of Re and/or PUVA, because the complete clearance rates and remission periods in FI(+) patients were comparable with those in FI(-) patients.

Adult↗
PubMed1990

Microcystic adnexal carcinoma: a light microscopic, immunohistochemical and ultrastructural study.

We report a case of microcystic adnexal carcinoma (MAC) occurring on the upper lip of an 82-year-old woman. Microscopically the tumor showed both pilar and sweat gland differentiation, involved the entire dermis and subcutaneous tissue, and invaded perineural spaces. Immunoperoxidase studies revealed carcinoembryonic antigen to be present in the ductal lining cells and in the amorphous content in the lumen, confirming sweat gland differentiation. The S-100 protein was positive in dendritic cells within the solid cell nests, but negative in cells lining cystic spaces. Ultrastructural study confirmed that the neoplasm was composed of two components, with pilar and eccrine differentiation. The former showed concentric layers of squamous epithelial cells with well-developed desmosomes and cytofilaments. The latter had ductal and alveolar structures; the ultrastructural features included: i) numerous villous folds of plasma membrane to interdigitate each other by focal desmosomes, ii) aggregates of cytofilaments, and iii) basally located myoepithelial cells which were separated from the surrounding stroma by rather thick basement membrane. In addition, distinct amyloid deposition was also observed on ultrastructural examination. To our knowledge, amyloid deposition has not been previously reported in MAC.

Aged↗
PubMed1990

Effects of demethylchlortetracycline phototoxicity on the structure and functions of rat liver mitochondria.

The phototoxic effects of demethylchlortetracycline (DMCT) with UVA radiation on isolated rat liver mitochondria were studied. DMCT at concentration of 21.5 microM with 5.53 x 10(-2) J cm-3 of UVA was found to be a potent uncoupler of oxidative phosphorylation. DMCT alone also uncoupled mitochondria but at higher concentrations (105 microM). ATPase activity was remarkably induced in mitochondria exposed to DMCT (21.5 microM) plus UVA (120% of DNP-stimulated ATPase activity). Content of ATP in such mitochondria when measured after addition of ADP was much smaller than that in control mitochondria. Ultrastructurally, mitochondria treated either with DMCT (21.5 microM) or with UVA alone stayed in the condensed configuration. On the other hand, uncoupled mitochondria treated with DMCT plus UVA became swollen and were changed into the orthodox configuration.

Animals↗
PubMed1990

PUVA increases ornithine decarboxylase gene expression in mouse skin.

The influence of topical PUVA on the activity of ornithine decarboxylase (ODC) and its gene expression was investigated in the skin of hairless mouse. After 1 h of application of 0.3% 8-methoxypsoralen, irradiation of 3 J/cm2 of ultraviolet A (UV-A) was administered. The ODC activity markedly increased and peaked at 24 h following UV-A irradiation. The ODC mRNA level, analyzed in dot-blot analysis, elevated to about 5 times that of control at 24 h after treatment. These results show that the PUVA-induced ODC activity is due in part to an increase in ODC gene expression.

Animals↗
PubMed1990

Vascular relaxation properties of calcitonin gene-related peptide and vasoactive intestinal polypeptide in subarachnoid hemorrhage.

The vascular relaxation effects of calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) on the dog basilar artery after experimentally produced subarachnoid hemorrhage (SAH) were examined in vitro by an isometric tension recording method. Both CGRP and VIP induced dose-dependent relaxations in ring segments of the intact basilar artery of control dogs. The vasorelaxant action of CGRP was more potent than that of VIP. The single-injection model of SAH was produced by injection of fresh autologous arterial blood (1 ml/kg body weight) into the cisterna magna on Day 0 of the post-SAH period, and the double-injection model was produced by two injections of blood (0.5 ml/kg each) on Days 0 and 2. Narrowing of the basilar arteries on vertebral angiograms was most prominent on Day 3 or 7 in the single- or double-injection model, respectively. Relaxation of the basilar artery induced by CGRP and VIP was to some extent decreased on Days 3 and 7 of the post-SAH period in the single-injection model, and on Days 7 and 14 in the double-injection model. However, the vasorelaxant effects of CGRP and VIP were significantly enhanced on Day 14 of the post-SAH period in the single-injection model, and on Days 28 and 42 in the double-injection model. Subsequently, these effects returned to control levels by Days 28 or 63 in the single- or double-injection model, respectively.

Animals↗
PubMed1990

Contraction phenomenon of type I collagen gel by melanoma cells.

In order to study the interaction between melanoma cells and collagen, B16 murine melanoma cells were embedded and cultured in type I collagen gel. Melanoma cells cultured in the collagen gel became elongated, as compared with those cultured on plastic, and some of them assumed a dendritic form. The gel contracted very slowly but steadily during culturing of melanoma cells, as in the experiment using fibroblasts. On the 20th day of culture the area of the gel accounted for only 32% of that when culture started. This contraction was enhanced by retinoic acid, which is known to induce cell differentiation. The contractility of the gel differed between various lines of melanoma cells. The present observations raise the possibility of interaction between melanoma cells and type I collagen.

Animals↗
PubMed1990

Correlation between ageing and collagen gel contractility of human fibroblasts.

To investigate the influence of ageing on wound healing, we cultured fibroblasts derived from human dermis in type I collagen gel, and evaluated the relationship between gel contractility and ageing. Cells were obtained from children (0-15 years old, Group A), early adulthood (16-40 years old, Group B), mid-adulthood (41-60 years old, Group C), and the elderly (61 or older, Group D). Gel contractility was determined by measuring the diameter on the second day after gel preparation. Within the tenth passage, gel contraction was the most marked in Group A, but did not differ among the other groups. Gel contraction at passages 30-40 did not differ from those within the tenth passage in Groups B, C and D, but it decreased markedly in Group A to a value similar to that in the other groups. These results show that fibroblasts in childhood are more contractile than those in adulthood and are more readily affected by passages (in vitro ageing).

Adolescent↗