Biomedical subjects

N Arai

Publications and source records attributed to N Arai.

At least 127 records · Page 7Linked to original sources

PubMed1997

The advantage of gastrectomized patients in management of their chronic hepatitis C.

Because the majority of patients with chronic hepatitis C do not respond to interferon, alternative treatments need to be established. Several lines of evidence suggest that iron depletion is beneficial for such patients. Thus, gastrectomized patients with a reduced capacity for iron absorption might have an advantage in treatment of their liver damage over patients with intact gastrointestinal tracts. Four male gastrectomized patients had post-transfusion chronic hepatitis C. The iron load in three patients was adjusted below 10 ng/ml of serum ferritin level by phlebotomy. Subsequent interferon treatment for the four patients without iron load cleared circulating hepatitis C virus RNA in one patient only. However, serum ferritin concentrations were stabilized at low levels without maintenance phlebotomy, and sustained normalization of serum liver enzyme activities was obtained in all four patients. Similar treatments were done for 10 male patients with intact gastrointestinal tracts. The amount of removed iron from these patients was more than that from gastrectomized patients. Interferon also failed to clear circulating hepatitis C virus RNA except in one case. Low ferritin levels and sustained normalization of liver enzymes were seen in three patients. A transient elevation of ferritin levels with low enzyme activities was seen in two patients. Relapsing hepatitis was seen in five of the seven patients who needed maintenance phlebotomy due to a rebound in serum ferritin levels, probably because of active iron absorption from the intestine. Our data suggest that depletion of cytotoxic iron is a key to managing patients with chronic hepatitis C.

Adult↗

PubMed1996

Signal transduction in Th clones: target of differential modulation by PGE2 may reside downstream of the PKC-dependent pathway.

Lymphokines produced by non-transformed Th clones, Th1 and Th2, were classified into three groups based on their patterns of expression by different stimuli: Group I, GM-CSF and IL-2, characterized by a strict requirement of activation of both the PKC- and calcium-dependent pathways; Group II, IFN-gamma, IL-3, and IL-4, partially induced by calcium ionophore alone; and Group III, IL-5, IL-6, and IL-10, partially induced by either PMA or calcium ionophore alone. Transfection of constitutively active PKC or p21ras replaced the requirement for PMA in expression of these lymphokines, with the exception of GM-CSF. Production of Group II lymphokines was partially induced by constitutively active calcineurin. Production of Group I and II lymphokines was highly sensitive to cyclosporin A, while Group III lymphokines were relatively resistant. Addition of prostaglandin E2 (PGE2) and overexpression of catalytic subunit of protein kinase A inhibited lymphokine production in Th1 cells, but not in Th2 cells, with the exception of GM-CSF. Production of Group III lymphokines induced by PMA alone was upregulated by PGE2, but that of Group II and III lymphokines induced by calcium ionophore alone was not affected. These results suggest that one of the targets of PGE2 is downstream of the PKC-dependent pathway.

Animals↗

PubMed1996

Combined effects of cabergoline and L-dopa on parkinsonism in MPTP-treated cynomolgus monkeys.

The behavioral effects of L-dopa or cabergoline alone were compared with those of the joint administration of the two drugs in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys with attention to the induction of hyperactivity and dyskinesia. Cabergoline alone at 0.2 mg/kg or less improved in a dose-dependent fashion the parkinsonism without inducing hyperactivity and dyskinesia following a single subcutaneous injection. L-dopa alone improved the parkinsonism, but induced hyperactivity and dyskinesia, depending on the dose applied. Doses required for 50% amelioration by L-dopa and cabergoline were 10 and 0.038 mg/kg, s.c., respectively. With low doses (50%-amelioration doses), cabergoline or L-dopa alone improved the parkinsonism without induction of hyperactivity and dyskinesia, but the duration of action was brief. Cabergoline in combination with L-dopa was highly effective in improving motor disability without induction of hyperactivity and dyskinesia. Moreover, the duration of action was more prolonged with the coadministration than with the single administration of each drug. These findings suggest that the combined therapy with low doses of L-dopa and cabergoline is beneficial for treating patients with advanced Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1996

Absence of SOD1 gene abnormalities in familial amyotrophic lateral sclerosis with posterior column involvement without Lewy-body-like hyaline inclusions.

A 65-year-old man with familial amyotrophic lateral sclerosis (ALS) with posterior column involvement showed fairly slow progression of the illness and lived with the aid of a respirator for 12 years. Neuropathological examinations showed simultaneous involvement of the pyramidal tract and lower motor neurons as well as degeneration in the Clarke's nucleus- spinocerebellar tract-middle root zone of the posterior column, the pallidoluysian system, the medullary reticular formation, and widespread anterolateral columns of the spinal cord. However, the patient had no Lewy-body-like hyaline inclusions, which are characteristic features of this form of familial ALS. Moreover, no abnormalities were found in his SOD1 cDNA sequences. There seem to be certain heterogeneities in familial ALS with posterior column involvement, and SOD1 gene abnormalities may be involved in the pathomechanism in rapidly progressing ALS, in which there are Lewy-body-like hyaline inclusions.

Aged↗

PubMed1996

Progressive supranuclear palsy with asymmetric lesions in the thalamus and cerebellum, with special reference to the unilateral predominance of many torpedoes.

This report concerns a notable case of progressive supranuclear palsy exhibiting asymmetric dentate nucleus and thalamic degeneration with numerous torpedoes. The neuronal loss in the ventral lateral nucleus of the thalamus was predominant on the right side, while in the cerebellum, a quantitative study revealed the contralateral predominance of the neuronal loss in the dentate nuclei and torpedo formation, with preserved Purkinje cells. The abnormal tau-protein-related profiles in the two nuclei did not show any laterality in their distribution, indicating that the dentatothalamic tract may have been affected in a non-specific way in this case. In addition, the fact that the prominent sites of torpedo formation and loss of dentate nucleus neurons are identical supports the hypothesis that the torpedoes may be formed in association with neuronal loss in the dentate nucleus because of a plausible metabolic change in Purkinje cells through synaptic detachment of their axon terminals.

Aged↗

PubMed1996

Dopamine receptor affinities in vitro and stereotypic activities in vivo of cabergoline in rats.

An ergot alkaloid derivative, cabergoline, and its metabolites were investigated for their affinities for dopamine D1 and D2 receptors in rat striatum in vitro in comparison with those of bromocriptine and pergolide. The affinity for D1 receptors was in the following order: pergolide > des-dimethylaminopropyl cabergoline (FCE21904) > cabergoline > or = bromocriptine > or = des-methyl cabergoline (FCE27395) > or = des-ethylcarbamoyl cabergoline (FCE21590). From the effects of GTP on these affinities for the D1 receptor, cabergoline, some of its metabolites, and pergolide were characterized as agonists in contrast to bromocriptine which was classified as an antagonist. The affinity for D2 receptors was ranked as follows: pergolide > or = cabergoline > or = FCE27395 > or = FCE21904 > bromocriptine > FCE21590 > carboxylic acid-type derivative of cabergoline (FCE21589). The affinity of each compound for the D2 receptor was much higher than that for the D1 receptor. The selectivity of cabergoline for D2 receptor was higher than those of bromocriptine and pergolide. Furthermore, these ergot alkaloids were investigated for eliciting stereotypy after subcutaneous administration to normal rats. Pergolide potently induced stereotypy at doses of 0.5 and 1.0 mg/kg, cabergoline slightly induced it only at a high dose of 2.0 mg/kg, whereas bromocriptine did not induce it at any of the doses tested, 10-40 mg/kg. These results suggest that pharmacological properties of cabergoline for the D1 and D2 receptors differ from those of bromocriptine and pergolide.

Animals↗

PubMed1996

Effect of cabergoline, a long-acting dopamine D2 agonist, on reserpine-treated rodents.

We studied the characterization of cabergoline, a new ergot alkaloid derivative and a selective dopamine D2 receptor agonist, in comparison to bromocriptine and pergolide in reserpine-treated rodents. Cabergoline (0.25-1.0 mg/kg, s.c.) improved dose-dependently the reserpine-induced akinesia that was assessed on the locomotor activity, and the efficacy lasted longer than those of bromocriptine (1.25-5.0 mg/kg, s.c.) or pergolide (0.0625-0.5 mg/kg s.c.). Cabergoline (ED50 = 1.10 mg/kg, at 4 h after the administration of drugs) also reversed catalepsy, the failure to correct an externally imposed posture, and its efficacy was stronger and longer than bromocriptine (ED50 = 4.65 mg/kg, at 4 h). Further, reserpine-induced rigidity was improved equally by cabergoline (0.125-1.0 mg/kg, i.v) and bromocriptine (1.0 mg/kg, i.v.). When cabergoline was administered together with 3(3,4-dihydroxyphenyl)-L-alanine (L-DOPA), the effects were additive. Our results indicate that the long-lasting effects of cabergoline could be beneficial for treating Parkinson's disease.

Animals↗

PubMed1996

Surgical treatment of children with medically intractable epilepsy--outcome of various surgical procedures.

Outcome after temporal lobe resection, extratemporal resection, and corpus callosotomy was studied in 33 children aged 15 years or less with medically intractable epilepsy. Seizure-free control was achieved in 67% (6/9) of pediatric patients versus 67% (60/90) of adult patients receiving temporal lobe resection and in 33% (4/12) of pediatric patients versus 25% (7/28) of adult patients receiving extratemporal resection. Among patients suffering from drop attacks and generalized convulsive seizures, 42% (5/12) of pediatric patients versus 25% (6/24) of adult patients receiving corpus callosotomy became seizure-free. The most prominent histological diagnoses in temporal lobe resections were three cases of mesial temporal sclerosis, four of ganglioglioma, and two of neuronal migration disorders. Neuronal migration disorders were the main histology in extratemporal resections. Four of five patients with behavioral problems treated by corpus callosotomy exhibited improved hyperactivity and/or attention deficits. There was no surgical morbidity or mortality. The outcome of pediatric patients was at least as favorable as that of adult patients, and improvement of behavioral disturbances could be expected after surgery. Surgical treatment is an effective and safe procedure for children with medically intractable epilepsy.

Adolescent↗

PubMed1996

Noninvasive evaluation of malignancy of brain tumors with proton MR spectroscopy.

PURPOSE: To test clinical proton MR spectroscopy as a noninvasive method for predicting tumor malignancy. METHODS: Water-suppressed single-voxel point resolved spectroscopy in the frontal white matter of 17 healthy volunteers and 25 patients with brain tumors yielded spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine (Cre), and lactate. These peak intensities were semiquantitated as a ratio to that of the external reference. The validity of the semiquantitation was first evaluated through phantom and volunteer experiments. RESULTS: The variation in measurements of the designated region in the volunteers was less than 10%. Normal ranges of NAA/reference, Cho/reference, and Cre/reference were 3.59 +/- 0.68, 1.96 +/- 0.66, and 1.53 +/- 0.64 (mean +/- SD), respectively. In 17 gliomas, the Cho/reference value in high-grade gliomas was significantly higher than in low-grade gliomas. Levels of NAA/reference were also significantly different in low-grade and high-grade malignancy. In eight meningiomas (four newly diagnosed and four recurrent), the level of Cho/reference was significantly higher in recurrent meningiomas than in normal white matter or in newly diagnosed meningiomas. CONCLUSIONS: Higher grades of brain tumors in this study were associated with higher Cho/reference and lower NAA/reference values. These results suggest that clinical proton MR spectroscopy may help predict tumor malignancy.

Adolescent↗

PubMed1996

[The dose-response relationship in treatment of strabismus with botulinum toxin].

The dose-response relationship between botulinum toxin and the alteration of ocular alignment of 15 esotropia cases (ET) and 15 exotropia cases (XT) was evaluated. We began with a dose of 0.25 units (U) per injection and stepped it up to 2.5 U per injection in ET and to 10 U per injection in XT. The average number of injections was 3.6 and 5.2, respectively. The maximum effect on ocular alignment developed 7 to 14 days after injection, and following recurrences ceased within 2 to 6 months, indicating a lasting effect. The maximum effect of each injection was within the limits of 10 to 30 prism diopters (delta). The maximum effect per unit dose of the small dose injection was greater than that of the large dose injection. In each dose, a greater effect was observed in the ET than in the XT, Recurrence was within the limits of 8 to 21 delta with both small dose injection and large dose injection. The recurrence amount per unit dose was greater with small dose injection than with large dose injection. The larger the dose injected, the more lasting was the effect obtained. This tendency was more prominent in ET than in XT. A roughly linear relationship between the dose and the ocular alignment was obtained on logarithmic graph paper, and the recurrence was reduced when the dose was increased. These findings suggest that repetitive injection effectively accumulates, resulting in a lasting effect.

Adolescent↗

PubMed1995

Definition of cis-regulatory elements of the mouse interleukin-5 gene promoter. Involvement of nuclear factor of activated T cell-related factors in interleukin-5 expression.

We have previously reported that the promoter region of the mouse interleukin-5 (IL-5) gene, extending from a nucleotide position about -1,200 to +33 relative to the transcription initiation site, can mediate transcriptional stimulation by phorbol 12-myristate 13-acetate and dibutyryl cAMP (Bt2cAMP) in mouse thymoma EL-4 cells. Here, we describe identification of four cis-regulatory elements necessary for full activity of the IL-5 promoter, using deletion and mutation analyses. We designated these elements as IL-5A (-948 approximately -933), IL-5P (-117 approximately -92), IL-5C (-74 approximately -56), and IL-5CLE0 (-55 approximately -38). We found that IL-5P bears homology to the binding site for the nuclear factor of activated T cells (NF-AT) and interacted with protein factors in nuclear extracts prepared from EL-4 cells stimulated with phorbol 12-myristate 13-acetate and Bt2cAMP (designated NFIL-5P). NFIL-5P complex was inhibited in the presence of an excess NF-AT and AP1 oligonucleotides and super-shifted by antisera raised against NF-ATp, c-Fos, and c-Jun. It thus seems likely that an NF-AT-related factor is involved in the regulation of IL-5 gene transcription.

Animals↗

PubMed1995

Positive and negative regulation of granulocyte-macrophage colony-stimulating factor promoter activity by AML1-related transcription factor, PEBP2.

The granulocyte-macrophage colony-stimulating factor (GM-CSF) gene promoter contains a consensus sequence for the polyomavirus enhancer binding-protein 2 (PEBP2) transcription factor, which consists of alpha and beta subunits. There are at least two genes, alpha A and alpha B, encoding the alpha subunit. alpha B is the mouse homologue of human AML1 gene detected at the breakpoints of t(8;21) and t(3;21) myeloid leukemias. We examined alpha A1 (an alpha A-gene product) and alpha B1 and alpha B2 (two alpha B-encoded isomers) for their effects on the GM-CSF promoter. PEBP2 alpha A1, alpha B1, and alpha B2 proteins bound the PEBP2 site within the mouse GM-CSF promoter. PEBP2 alpha A1 and alpha B1 enhanced the expression of the GM-CSF promoter-driven reporter plasmid in unstimulated and 12-O-tetradecanoylphorbol 13-acetate/phytohemagglutinin-stimulated human Jurkat T cells. In contrast, the promoter activity was suppressed by alpha B2. Coexpression of alpha B1 and alpha B2 showed that the promoter activity could be determined by the alpha B1/alpha B2 ratio. Jurkat cell extract contained PEBP2 site-binding protein(s) that cross-reacted with antimouse alpha A1 antibodies. Northern blot analysis indicated the expression of human PEBP2 alpha A, alpha B (AML1), and beta genes in Jurkat cells. Although further studies are required to determine the precise role of PEBP2 in the GM-CSF promoter activity, the present findings suggested the importance of the relative ratio of different PEBP2 isoforms in regulating the levels of the promoter activity.

Animals↗

PubMed1995

Numerous glial fibrillary tangles in oligodendroglia in cases of subacute sclerosing panencephalitis with neurofibrillary tangles.

Both neurons and oligodendroglia are preferentially infected in subacute sclerosing panencephalitis (SSPE). Massive argyrophilic and tau-positive glial fibrillary tangles (GFT) were found in oligodendroglia in two autopsy cases of SSPE with neurofibrillary tangles (NFT). GFT shared common phosphorylated tau-epitopes with NFT, but were negative for ubiquitin. Electron microscopically, GFT consisted of compact bundles of irregularly woven tubules. Thus, GFT in SSPE differed from NFT showing regular constriction of tubules and from GFT in some other cytoskeletal disorders in which GFT reportedly consisted of straight tubules.

Adolescent↗

PubMed1995

Cyclic AMP inhibits expression of the IL-2 gene through the nuclear factor of activated T cells (NF-AT) site, and transfection of NF-AT cDNAs abrogates the sensitivity of EL-4 cells to cyclic AMP.

cAMP inhibits PMA-induced IL-2 production at the transcriptional level in EL-4, a mouse lymphoma line. The region of the mouse IL-2 promoter covering positions from -321 to +46 relative to the transcription initiation site is required for activation by PMA and inhibition by cAMP. This region contains the nuclear factor of activated T cells (NF-AT), nuclear factor-kappa B (NF-kappa B), AP-1, and Oct binding sites, and the role of each element in responding to PMA and/or cAMP signals was characterized. The IL-2 promoter carrying mutations in each element reduced response to PMA while it retained sensitivity to cAMP, thereby suggesting that multiple elements contribute to positive and negative responses to PMA and cAMP, respectively. Using reporter plasmid carrying multiple copies of each element, we then found that the NF-AT construct was most effective in responding to PMA activation and to cAMP inhibition. Electrophoretic mobility shift assay revealed that, after exposure of cells to Bt2cAMP, NF-AT binding complex changed in amount or in mobility as a function of time. Furthermore, overexpression of the cytoplasmic component of NF-AT abrogated the inhibitory action of cAMP. These results indicate that the NF-AT site is a target of the inhibitory action of cAMP. In addition, binding of the NF-kappa B (p50/p65) heterodimer to the NF-kappa B site was inhibited by cAMP. Taken together, our data show that cAMP in EL-4 cells inhibits mouse IL-2 gene transcription through cis regulatory elements that include the NF-AT site as well as the NF-kappa B site.

Amino Acid Sequence↗

PubMed1995

Expression of the Fas ligand in cells of T cell lineage.

Fas ligand (FasL) is a membrane-type cytokine belonging to the TNF family, and induces apoptosis through its cell-surface receptor, Fas. To determine the cell types that express FasL, various mouse tissues and cell lines were examined by Northern hybridization using a mouse FasL cDNA as a probe. Among tissues, lymphoid organs (thymus, lymph node, spleen), lung, and small intestine express low levels of FasL mRNA, suggesting the role of FasL in the general immune system and mucosal immunity. The testis expressed FasL mRNA most abundantly; however, the size of FasL mRNA in the testis was slightly shorter than those in other tissues. Distribution of FasL mRNA in a panel of cell lines indicated that the FasL expression is rather restricted to the cells of T cell lineage. Activation of the splenocytes with the T cell activators such as PMA and ionomycin, Con A, anti-CD3, or even IL-2 alone induced the expression of the FasL. CD8+ splenocytes expressed the FasL more abundantly than did the CD4+ splenocytes upon activation by Con A and IL-2. Among CD4+ CTL cell lines, the FasL was expressed in all Th1 and Th0, and some Th2 clones.

Animals↗

PubMed1995

Cis-acting DNA elements of mouse granulocyte-macrophage colony-stimulating factor gene responsive to Fc epsilon receptor cross-linking stimulation in the mouse mast cell line MC/9.

Mouse mast cells produce many kinds of cytokines in response to cross-linking of high affinity Fc epsilon receptor (Fc epsilon RI). Among these cytokines, granulocyte-macrophage CSF (GM-CSF) gene induction in mouse mast cells has been reported to be regulated at both the transcriptional level and the post-transcriptional level. We analyzed the mechanism of the transcriptional regulation of GM-CSF gene induction through Fc epsilon RI cross-linking stimulation in the mouse mast cell line MC/9. In MC/9, the GM-CSF gene was activated transcriptionally by Fc epsilon RI cross-linking stimulation. The 5' deletion analysis of GM-CSF gene promoter indicated that the 5' boundary of the responsive promoter region lay between positions -113 and -95. When the deletion was extended to positions -72 or -60, the stimulatory effect was significantly diminished. We then examined 3' deletion of pmGMCAT -113 from position -60. This analysis indicated that the 3' boundary lay between positions -84 and -72. No subfragments of the region spanning positions -113 to -72 could cover the full induction level. A site-directed mutagenesis experiment revealed that the sequence spanning positions -108 to -72 was needed for full activation. These data indicate that GM-CSF gene in mast cells is activated mainly through the sequence spanning positions -108 to -72.

Animals↗

PubMed1995

Expression of bone sialoprotein mRNA during bone formation and resorption induced by colchicine in rat tibial bone marrow cavity.

In the rat tibial bone marrow cavity, following colchicine injection, there is a phase of osteogenesis in which bone trabeculae replace the necrotic bone marrow tissues and fill the marrow cavity. The newly formed bone is subsequently resorbed by osteoclasts and normal bone marrow is restored. In this study, we correlated these morphologic events with the pattern of gene expression of bone sialoprotein (BSP), an extracellular matrix protein in mineralized tissues, to elucidate the possible functions of BSP in bone formation and resorption in vivo. The expressions of osteopontin (OPN) and type I collagen were also examined. Northern hybridization of the tibia demonstrated that OPN mRNA was gradually increased and expressed at a maximal level 10 days after colchicine injection (during the bone resorption process), while BSP mRNA expression already reached a maximal level at day 6 (during the initial process of bone formation). Its expression was, thus, quite temporary at the beginning of bone formation and different from that of type I collagen, which was continually elevated from days 6 to 10. In situ hybridization of the newly formed bone induced in the tibia revealed that BSP mRNA was evenly expressed in most osteoblasts and osteocytes, moreover in interconnecting colonies of spindle-shaped cells, possibly preosteoblasts, at day 6. At day 10, however, its expression became restricted to some cells on the bone surfaces, some osteoblasts, and most osteoclasts. These observations suggest that BSP may play an important role mainly in the initiation of bone formation and is also associated with the functions of osteoclast in vivo.

Amino Acid Sequence↗

PubMed1995

Differential effects of three dopamine receptor agonists in MPTP-treated monkeys.

The behavioral effects of cabergoline, pergolide and bromocriptine were investigated in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned parkinsonian cynomolgus monkeys with attention to the induction of hyperactivity, as evidenced by irritability, excitability and aggressiveness. All three drugs improved the parkinsonism in a dose-dependent fashion following a single injection. Among the three dopamine (DA) receptor agonists used, the antiparkinsonian effect of pergolide was the strongest and had an immediate effect, while cabergoline showed the longest duration of the antiparkinsonian effect and was least potent in inducing hyperactivity.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗