Search PubMed⌕ Search

Biomedical subjects

M Arai

Publications and source records attributed to M Arai.

At least 19 recordsLinked to original sources
PubMed1992

Immunohistochemical localization of calretinin in the rat lateral geniculate nucleus and its retino-geniculate projection.

In the present study, we examined the distribution of calretinin-immunoreactive neuronal cell bodies and fibers in the lateral geniculate nucleus of the rat. In normal rats, clusters of immunoreactive cell bodies were found in: (i) the rostral portion of the ventral lateral geniculate nucleus pars medialis (VLGM), (ii) the intergeniculate leaflet (IGL), (iii) the intermediate region between the VLGM and the ventral lateral geniculate nucleus pars lateralis (VLGL), (iv) the caudomedial portion of the VLGM, and (v) the caudolateral portion of the VLGM. In the dorsal lateral geniculate nucleus (DLG), immunoreactive cell bodies were rarely observed. After uni- or bilateral eye enucleation, no significant alteration in the morphological features or distribution of immunoreactive cell bodies was detected in the lateral geniculate nucleus. In normal rats, immunoreactive fibers formed dense plexuses in: (i) the DLG, (ii) the external layer of the VLGL, (iii) the internal layer of the VLGL, (iv) the IGL, (v) the caudomedial portion of the VLGM, and (vi) the optic tract. After unilateral eye enucleation, immunoreactive fibers in the external layer of the VLG and in the optic tract almost totally disappeared on the contralateral side to the lesion. Unilateral eye enucleation caused a significant decrease of immunoreactive fibers in the DLG and in the internal layer of the VLGL, but a substantial number of immunoreactive fibers still remained there. In the IGL and the caudomedial portion of the VLGM, no observable alteration in the distribution of immunoreactive fibers was detected after uni- or bilateral eye enucleation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Isolation and characterization of type IX collagen-proteoglycan from the Swarm rat chondrosarcoma.

Type IX collagen was partially purified from the Swarm rat chondrosarcoma by a series of a conventional salting-out procedures. The preparation was further separated by anion exchange chromatography into an unbound and a bound fraction in an A230 ratio of about 5:1. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the bound fraction appeared as a broad band, whose molecular mass ranged from 250 to 270 kDa. Digestion with chondroitinase ABC reduced the apparent molecular mass of the bound fraction to about 250 kDa, a value comparable to the molecular mass of the unbound fraction. Tryptic peptide maps of the protein moieties of unbound and bound forms showed that their molecular structures were basically identical. A monoclonal antibody specific for LMW, one of the pepsin-resistant fragments of the rat sarcoma type IX, reacted with both the unbound and bound fractions. Together the results indicate that the unbound and bound fractions represent a type IX collagen devoid of the chondroitin sulfate chain and its proteoglycan form with covalently bound chondroitin sulfate, respectively. The extent of glycosaminoglycan attachment to type IX collagen molecules in rat chondrosarcoma (about 16%) is quite different from the extents described in chick embryo cartilage (about 80%), chick vitreous humour (100%) and bovine cartilage (less than 5%). Further studies on the neoplastic tissue will offer additional information regarding the biological basis and biological consequences of the glycosaminoglycan attachment to type IX collagen molecules.

Animals↗
PubMed1992

Occurrence of collagen and proteoglycan forms of type IX collagen in chick embryo cartilage. Production and characterization of a collagen form-specific antibody.

Type IX collagen from chick embryonic cartilage is a proteoglycan bearing a single chondroitin sulfate chain covalently linked to the alpha 2(IX) polypeptide chain. We have isolated type IX collagen metabolically labeled with [3H]proline using an antibody to type IX collagen and have found that the molecule is synthesized in two forms, a collagen form (COLIX) and a proteoglycan form (PGIX). In cultured chondrocytes, the two forms of type IX collagen showed a different ability to be deposited in the matrix. We have suggested the possibility that both forms may arise from an alternative substitution of a chondroitin sulfate chain to the NC3 domain of the alpha 2(IX) chain. Based on the reported amino acid sequence at the NC3 domain of alpha 2(IX), we have synthesized undecapeptides containing the sequence around the glycosaminoglycan attachment site of the alpha 2(IX) chain. Antibody against the peptide, which was raised in rabbit, only recognized COLIX and made it possible to distinguish COLIX from PGIX. Evidence shows that this could be due to a difference in antigenicity of the NC3 domain of the alpha 2(IX) chain between COLIX and PGIX caused by the substitution of a chondroitin sulfate chain to the serine residue in this domain. Therefore, this antibody may be useful as a probe for studies on the functions of glycosaminoglycan substitution in type IX collagen.

Amino Acid Sequence↗
PubMed1992

Evaluation of selected plants for their toxic effects in canaries.

Leaves or fruit from 14 plants considered to be toxic to pet birds were administered by gavage to 15 pairs of canaries (Serinus canaria). Each bird was given 0.12 to 0.70 g of plant material. One pair served as a control and was given distilled water. The plant materials were flash-frozen in liquid nitrogen, pulverized, and resuspended in deionized water for administration. Of the plants tested, 5 (oleander, lupine, foxglove, yew leaves, and dieffenbachia) were considered highly toxic and were associated with acute death of birds. The remaining plant samples caused no, or only transient, clinical illness.

Animals↗
PubMed1992

Endothelin-1 stimulates c-fos mRNA expression and acts as a modulator on cell proliferation of rat FRTL5 thyroid cells.

In FRTL5 thyroid cells, endothelin (ET)-1 alone had no effect on DNA synthesis but caused a transient increase in c-fos mRNA levels and stimulated IGF-I induced DNA synthesis and cell proliferation. By contrast, ET-1 inhibited the stimulatory effects of TSH actions on DNA synthesis, cell proliferation and c-AMP production. 8-Bromo-cAMP-induced DNA synthesis was also inhibited by ET-1, suggesting that ET-1 exerts its inhibitory effects at step(s) involving cAMP production and post cAMP pathway. ET-1-induced suppression of TSH actions were reversed by a C-kinase inhibitor, H-7. These results suggest that the effect of ET on functions of FRTL5 cells is, at least, in part mediated by C-kinase dependent pathway.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Evaluation of selected plants for acute toxicosis in budgerigars.

Pairs of budgerigars were given samples, by gavage, of plants considered potentially toxic to pet birds. Samples were prepared by flash-freezing and powdering fresh plant material in liquid nitrogen and resuspending the material in deionized water for administration. Of the 19 plants tested, only 6 induced clinical signs of illness; these plants included yew, oleander, clematis, avocado, black locust, and Virginia creeper (Taxus media, Nerium oleander, Clematis sp, Persea americana, Robinia pseudoacacia, Parthenocissus quinquefolio).

Acacia↗
PubMed1992

Coronary angioplasty using an over-the-wire balloon catheter through a new 6 French guiding catheter.

A new 6 French (F) guiding catheter with a large, teflon-coated internal lumen (4.2F) was developed, permitting use of the standard ultralow profile (less than 3F) over-the-wire system. This small coronary angioplasty system (6F-PTCA) was evaluated in 48 lesions in 45 of 137 patients (33%) who underwent coronary angioplasty between September 1990 and January 1991. The mean age was 64 years (range 49 to 82); 37 (82%) were male. The procedure was via the brachial artery in 28 patients (62%). The overall primary success rate was 96%. It was 100% via the brachial artery and 90% via the femoral artery. There were no major complications. The puncture compression time with the 6F-PTCA via the brachial artery and via the femoral and with 8F-PTCA via the femoral was 3.8, 9.6, and 16.9 hr, respectively (P less than 0.001), although the procedure time of the 6F-PTCA via brachial and via femoral and of the 8F-PTCA was not significantly different. The mean hospital stay was 3.1, 4.5, and 5.5 days, respectively (P less than 0.01). A small hematoma occurred in 2 patients (4.4%) after the 6F-PTCA and in 3 (3.3%) after 8F-PTCA, and a large hematoma (greater than 5 cm) was noted in 7 patients (7.6%) after 8F-PTCA. These results indicate that coronary angioplasty using the over-the-wire system through the new 6F guiding catheter is technically feasible. Moreover, this approach, especially when advanced via the brachial artery, could shorten the hemostasis time and facilitate early ambulation.

Aged↗
PubMed1992

Characterization of a novel mRNA expressed by neurons in mature brain.

In previous studies, differential hybridization screening of an activated murine T-lymphocyte cDNA library identified an interleukin 2-responsive mRNA, designated F5, expressed in lymphoid tissues and brain only. We now report characterization of a full-length clone isolated from an adult mouse brain cDNA library. Neither the nucleic acid nor amino acid sequences demonstrated similarity to reported sequences. On Southern blotting, the protein coding sequence hybridized to genomic DNA from a variety of species. On Northern blotting, F5 mRNA was expressed in adult mouse brain, spinal cord, eye, and dorsal root ganglia but not in peripheral nerve. In situ hybridization studies demonstrated prominent expression by neurons in brain. F5 mRNA expression was undetectable in embryonic rat cerebral hemisphere and low until postnatal day 21. F5 is a novel mRNA selectively expressed by proliferating lymphocytes and mature neurons.

Amino Acid Sequence↗
PubMed1992

Expression of the neu proto-oncogene by Schwann cells during peripheral nerve development and Wallerian degeneration.

The neu gene, which encodes a putative tyrosine kinase growth factor receptor termed p185neu, was originally identified as a dominant transforming gene in neurogliomas and schwannomas induced by transplacental treatment of rat embryos with ethylnitrosourea. The present studies were undertaken to determine the expression pattern of the neu gene in peripheral nerve. Northern blot analysis of total RNA isolated from rat sciatic nerves demonstrated prominent neu mRNA expression on postnatal days 1 and 7, with substantially lower expression up to adulthood. Immunohistochemical studies confirmed expression of p185neu by Schwann cells (SC) in developing sciatic nerve and minimal p185neu immunoreactivity in adult nerves. However, neu mRNA and p185neu protein progressively increased following sciatic nerve transection in adult animals. In addition, neu mRNA and p185neu were found in neonatal rat sciatic nerve SC and several SC-derived cell lines. In resting SC, neu mRNA was expressed at a low level, but was greatly increased by treatment with forskolin and glial growth factor. These studies demonstrate that the neu gene and its protein product, p185neu, are expressed by SC both in vivo and in vitro and suggest that p185neu plays a role in the regulation of SC proliferation or differentiation.

Animals↗
PubMed1992

Expression of the T-lymphocyte activation gene, F5, by mature neurons.

F5 was first identified as an mRNA expressed by activated but not resting T-lymphocytes. Subsequent studies suggested that it also is selectively expressed by mature neurons. Although the F5 protein coding sequence is highly conserved, the function of the F5-encoded protein is unknown. The present studies were undertaken to define the anatomic distribution, cellular specificity, and developmental pattern of F5 mRNA expression in the mouse nervous system, addressing specifically the question of whether the expression pattern of F5 corresponds to that of known ligand-receptor or signal-transduction systems. The use of a nonradioactive in situ hybridization method and paraffin-embedded sections provided excellent morphological preservation and a high degree of cellular resolution. F5 mRNA was detected in the central nervous system, peripheral nervous system, and retina in cells having the location and morphological features of neurons. Combined in situ hybridization histochemistry for F5 mRNA and immunofluorescence staining for cell-specific markers confirmed that neurons expressed F5 mRNA but astrocytes did not. The neuronal expression of F5 mRNA had two interesting features. First, the level of expression appeared to correlate directly with the size of the neuronal perikarya, the length of the axonal projection, or the extent of dendritic arborization. Second, F5 mRNA appeared late in post-natal development. These observations are of interest because of preliminary data suggesting that F5 may function as a substrate for protein kinase C, which demonstrates a similar expression pattern in the nervous system.

Animals↗
PubMed1992

The regulation of calcium cycling in stressed hearts.

Myothermal measurements of tension-independent heat are used to calculate the quantity of calcium released during isometric contraction and the rate at which it is removed in control, thyrotoxic and pressure-overloaded rabbit hearts. Experiments were carried out at 30 degrees C. In control rabbit hearts 41.0 +/- 7.0 nmoles/g Ca++ was released into the cytosol for each beat, while the rate at which the Ca++ was removed from the cytosol was 24.4 +/- 4.4 nmoles/g sec. In the presence-overloaded preparations, the amount of calcium released and the rate of calcium removal were 41% and 40% of control values. This reduction was correlated with the mRNA levels for the sarcoplasmic reticulum (SR) Ca++ ATPase, phospholamban and the ryanodine receptor. The depression was also correlated with a reduction in SR Ca++ ATPase protein expression. In thyrotoxic hearts compared with controls, with each activation there is an increase in the amount of calcium liberated into the cytosol (39%) and the rate of calcium removal (31%). This increase is correlated with an increase in the mRNA and protein expression for the SR Ca++ ATPase as well as the mRNA for the ryanodine receptor. Calsequestrin mRNA was unchanged in all of the experimental preparations. It is suggested that the alteration in the calcium cycling proteins offers at least a partial explanation for the changes in calcium cycling measured in response to the stresses applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Ataxic polyneuropathy and anti-Pr2 IgM kappa M proteinemia.

A case of ataxic neuropathy associated with IgM kappa M proteinemia is reported. Double filtration plasmapheresis effectively treated the neuropathy. The IgM kappa antibody had anti-Pr2 cold agglutinin activity. We demonstrated reactivities of the IgM kappa antibody to sialosyl paragloboside, sialosyl lactosaminyl paragloboside, GT1b, GD1a, GD1b, GM3 and GD3 on high-performance thin-layer chromatography immunostaining and enzyme-linked immunosorbent assay, which is previously unreported antigenic specificity of the M proteins in cases of paraproteinemic neuropathy. IgM M protein with anti-Pr2 cold agglutinin activity may play a pathogenetic role in peripheral nerve demyelination, because the target antigens of the M protein are present in myelin and possibly in endothelial cells of the peripheral nervous system.

Ataxia↗
PubMed1992

Thyroid ultrasonography related to clinical and laboratory findings in patients with silent thyroiditis.

We summarized the clinical course of 10 patients with silent thyroiditis and evaluated the clinical usefulness of ultrasonography, in combination with clinical and laboratory findings, for the differentiation from Graves' disease. Serum T3 and T4 were increased in all cases, and the ratio of T3/T4 (ng/micrograms) was 17.8 +/- 3.6 (SD). But in 3 of 10 patients the ratio was greater that 20. TSH receptor antibody (TRAb) and thyroid stimulating antibody (TSAb) were negative in all cases. The estimated thyroid volume by ultrasonography was 18.4 +/- 5.5 ml, which was slightly increased but significantly lower than those in Graves' disease (p less than 0.05). The internal texture of the thyroid showed a decreased echogenicity with a mean echo level of 70.4 +/- 15.4. There was a weak positive correlation between the echo level at the onset of thyrotoxicosis and the lowest T3 level during the clinical course (p less than 0.05). It is suggested that ultrasonography gives a useful information to the diagnosis and outcome of patients with silent thyroiditis.

Adult↗
PubMed1992

Cluster of fibronectin type III repeats found in the human major histocompatibility complex class III region shows the highest homology with the repeats in an extracellular matrix protein, tenascin.

Walking and sequencing a genome portion centromeric of CYP21B in the human MHC class III region disclosed a cluster of fibronectin type III repeats in an approximately 50-kb DNA segment. Fibronectin type III repeats are known to consist of ca. 90 amino acid residues and exist in a wide range of protein species. Homology searches in protein databases showed that the repeats found had the highest homology with the repeats of human tenascin, an extracellular matrix protein. One cDNA sequence located immediately centromeric of CYP21B, the 3' portion of which is transcribed by the opposite strand of CYP21B, was found also to have six type III repeats followed by a fibrinogen domain. Pairwise homology comparison of these repeats in the MHC locus with those of human tenascin showed a general parallelism in their gene organization, indicating that the newly found repeats are elements of certain tenascin-like genea.

Amino Acid Sequence↗
PubMed1992

The influence of argon laser panretinal photocoagulation on the rabbit ERG c-wave.

We observed the influence of panretinal photocoagulation on the ERG c-wave in rabbit eyes. DC-registered ERGs were recorded from rabbit eyes before and after photocoagulation, and compared with those of the fellow eyes. The rabbits were subdivided into 3 groups according to application numbers: 500, 1000, and 1500 spots. The ERG c-waves were found to have totally disappeared in all rabbits 3 days after panretinal photocoagulation, then reappeared with various intervals. In the 500 spot group, the c-wave reappeared after one week, and almost reached control levels in one and a half months. In the 1000 spot group, a 10 day delay was noted, and 90% of control levels were regained after 6 months. In the 1500 spot group, the c-wave didn't reappear until 2 weeks later, and regained 70% (of the control level) after 6 months. The recovery rates were related to the number of laser applications. These results indicate that the ultimate degree of recovery in c-wave amplitude and the time required for the reestablishment of retinal pigment epithelium function both depend on the size of the coagulated area.

Animals↗
PubMed1992

Structural identification of an epitope of antigenic factor 5 in mannans of Candida albicans NIH B-792 (serotype B) and J-1012 (serotype A) as beta-1,2-linked oligomannosyl residues.

In previous articles, we reported the presence of phosphate-bound beta-1,2-linked oligomannosyl residues in the mannans of strains of Candida albicans serotypes A and B and Candida stellatoidea. To identify the antigenic factor corresponding to this type of oligomannosyl residue, a relationship between chemical structure and antigenic specificity in the mannans of C. albicans NIH B-792 (serotype B, B-strain) and C. albicans J-1012 (serotype A, J-strain) was investigated by using a combination of two-dimensional 1H nuclear magnetic resonance spectroscopy of H-1, H-2, and H-5 regions in the mannans and an enzyme-linked immunosorbent assay that employed concanavalin A-coated microtiter plates. It was shown in the present 1H nuclear magnetic resonance study that an examination of chemical shifts not only in the H-1 region but also in the H-5 region was useful for the quantitative determination of the phosphate-bound beta-1,2-linked oligomannosyl residues. In the enzyme-linked immunosorbent assay using concanavalin A-coated plates, it was revealed that, of factor sera 1, 4, and 5, only factor serum 5 showed a reactivity proportional to the densities of the beta-1,2-linked oligomannosyl residues of the mannan subfractions of different phosphate contents that had been prepared from the bulk B-strain mannan by DEAE-Sephadex chromatography. The above results indicate that the phosphate-bound beta-1,2-linked oligomannosyl residues, Manp beta 1----(2Manp beta 1----)n2Man (n = 0-5), correspond to antigenic factor 5.

Antigens, Fungal↗
PubMed1992

Regulation of sarcoplasmic reticulum gene expression during cardiac and skeletal muscle development.

The expression of major sarcoplasmic reticulum proteins during cardiac and fast-twitch skeletal muscle development was examined using gene-specific probes. Through the use of S1 nuclease mapping, Northern blot, and RNA slot-blot analysis, sarcoplasmic reticulum proteins were shown to exhibit both narrow tissue specificity and plasticity in their expression during muscle development. In fast-twitch skeletal muscle, the cardiac/slow-twitch isoforms of Ca(2+)-ATPase and calsequestrin were detected at high levels in fetal stages but were gradually replaced by fast-twitch isoforms in adult muscle. In contrast, cardiac muscle expressed exclusively cardiac/slow-twitch isoforms of Ca(2+)-ATPase and calsequestrin at all stages. Both fast-twitch and slow-twitch skeletal muscle expressed the same skeletal muscle ryanodine receptor isoform, whereas cardiac muscle expressed a cardiac isoform. Phospholamban expression was restricted to cardiac and slow-twitch skeletal muscle and did not appear in developing fast-twitch skeletal muscle. During in vitro myogenesis of C2C12 cells, the mRNA transcripts encoding sarcoplasmic reticulum proteins were found to be coordinately induced in synchrony with that of contractile protein mRNA. The myogenic factor "myogenin" induced sarcoplasmic reticulum gene transcripts along with contractile protein mRNAs in nonmyogenic cells. These data suggest that the induction of both sarcoplasmic reticulum and contractile protein gene families is under the control of a common myogenic differentiation program.

Actins↗