Biomedical subjects

S Tanaka

Publications and source records attributed to S Tanaka.

At least 397 records · Page 22Linked to original sources

PubMed2000

Hormonal control of body-color polymorphism in Locusta migratoria: interaction between

The effects of injection of [His(7)]-corazonin and juvenile hormone (JH) III on the body color in L. migratoria were investigated using albino and normal (pigmented) nymphs. Most albino nymphs turned green in the fourth instar if injected with JH III during the last 2 days of the previous instar. When albino third instar nymphs injected with 10 pmol of [His(7)]-corazonin on different days were treated with 100 µg of JH III on day 3.5, they developed various body colors in the following nymphal instar: those injected with [His(7)]-corazonin during the first 2 days developed very dark green or black color, whereas some of those injected after this period turned green and their legs and ventral side of the body were variously pigmented, the coloration being similar to green solitary individuals often found in the field. Field-collected brown solitary nymphs injected with 1 nmol of [His(7)]-corazonin and kept individually, turned reddish without any black spots in the following nymphal instar when the ecdysis occurred within 1 day after injection. Injection of [His(7)]-corazonin 2 days before the following ecdysis induced black patterns on an orange background color, the coloration characteristic of gregarious forms. Similar injections into field-collected green solitary nymphs also induced black patterns but the rest of their body remained green. These results may indicate that the temporal changes in the hemolymph titers of [His(7)]-corazonin and JH play an important role in the control of body-color polymorphism in this locust.

Journal Article↗

PubMed2000

[A method for culturing Artemia].

Artemia sp. is classified into phylum Arthropoda and class Crustacea. Ecological and experimental studies of this animal have been reported using wild species. In order to isolate inbred strains of Artemia, we have established a subculturing method for siblings of Artemia. Details of our practice on the culturing method of Artemia are described and the recent classification of Artemia is presented.

Animal Husbandry↗

PubMed2000

Thrombopoietin and interleukin-2 induce association of CRK with STAT5.

Crk (Crk I and II) proteins and closely related CrkL are adapters which are commonly involved in various signaling processes in various cells, and these proteins share many ligands. Whether they have redundant or distinct physiologic roles is unclear. By coprecipitation and far Western blotting analysis, we demonstrate that Crk (I/II) binds to tyrosine phosphorylated STAT5 in cells stimulated by cytokines such as thrombopoietin (TPO) and interleukin-2 (IL-2). The association did not require nuclear elements and can be observed in primary cells as this was also demonstrated in TPO-stimulated platelets. Using a beta-casein promoter STAT5 binding site as a probe, we have also demonstrated that CrkL (a close relative of Crk) antiserum, but not Crk antiserum, supershifted the STAT5-DNA complex by an electrophoretic mobility shift assay, suggesting that CrkL, but not Crk, is the major component of the complex. Thus, Crk and CrkL may have distinct roles in the regulation of STAT5.

Base Sequence↗

PubMed2000

Arginine-rich peptides. An abundant source of membrane-permeable peptides having potential as carriers for intracellular protein delivery.

A basic peptide derived from human immunodeficiency virus (HIV)-1 Tat protein (positions 48-60) has been reported to have the ability to translocate through the cell membranes and accumulate in the nucleus, the characteristics of which are utilized for the delivery of exogenous proteins into cells. Based on the fluorescence microscopic observations of mouse macrophage RAW264.7 cells, we found that various arginine-rich peptides have a translocation activity very similar to Tat-(48-60). These included such peptides as the d-amino acid- and arginine-substituted Tat-(48-60), the RNA-binding peptides derived from virus proteins, such as HIV-1 Rev, and flock house virus coat proteins, and the DNA binding segments of leucine zipper proteins, such as cancer-related proteins c-Fos and c-Jun, and the yeast transcription factor GCN4. These segments have no specific primary and secondary structures in common except that they have several arginine residues in the sequences. Moreover, these peptides were able to be internalized even at 4 degrees C. These results strongly suggested the possible existence of a common internalization mechanism ubiquitous to arginine-rich peptides, which is not explained by a typical endocytosis. Using (Arg)(n) (n = 4-16) peptides, we also demonstrated that there would be an optimal number of arginine residues (n approximately 8) for the efficient translocation.

Amino Acid Sequence↗

PubMed2000

Prostaglandin E(2) receptors, EP2 and EP4, differentially modulate TNF-alpha and IL-6 production induced by lipopolysaccharide in mouse peritoneal neutrophils.

The expression and function of prostaglandin (PG) E(2) receptors were examined in mouse neutrophils exudated into the peritoneal cavity by casein treatment. Expressions of the EP2 and EP4 receptors were detected in neutrophils by Northern blot, but those of EP1 and EP3 receptors were not detected by RT-PCR. EP2-selective agonist, ONO-AE1-259, and EP4-selective agonist, ONO-AE1-329, stimulated cAMP formation in the cells. PGE(2) affected the TNF-alpha and IL-6 production in lipopolysaccharide (LPS)-treated neutrophils; it suppressed the TNF-alpha production and enhanced the IL-6 production. The PGE(2) effects were mimicked by dibutyryl cAMP. This is the first study of the enhancement of IL-6 production by cAMP-elevating reagents in neutrophils. Using neutrophils from EP2- and EP4-deficient mice in combination with EP2- and EP4-selective agonists, it was found that the augmentation of IL-6 was mediated mainly by the EP2 receptor and the suppression of TNF-alpha by the EP4 receptor and partially by the EP2 receptor. These findings indicate that casein-induced peritoneal neutrophils express Gs-coupled PGE(2) receptors, EP2 and EP4, which might differentially regulate the LPS-induced production of TNF-alpha and IL-6.

Animals↗

PubMed2000

Simultaneous chiral analysis of methamphetamine and related compounds by capillary electrophoresis.

A capillary electrophoretic method for the simultaneous chiral analysis of nine cationic drugs (18 enantiomers) has been developed. These drugs are methamphetamine (MA), amphetamine, dimethylamphetamine, ephedrine (EP), norephedrine, methylephedrine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxy-N-ethylamphetamine. The chiral selector, which was added to the electrolyte, was a mixture of beta-cyclodextrin and heptakis(2,6-di-O-methyl)-beta-cyclodextrin. The detection limits of all enantiomers were 0.1 microg/ml, and the intermediate precisions of migration time and peak area of within-run assays (n=6) were under 0.3% and 1.4%, respectively. The calibration curves of the peak area of (1R,2S)-(-)-EP and S-(+)-MA were linear in the range 0.2-500 microg/ml. This method was applicable to urine analysis.

Calibration↗

PubMed2000

Dendritic cell-like immunoreactivity in the glomerulus of the olfactory bulb and olfactory nerves of mice.

Dendritic cell-like immunoreactivity was examined in the mouse brain. The glomerulus of the olfactory bulb and the olfactory nerves were stained by antibodies against the dendritic cells, NLDC-145 and MIDC-8, while these structures were not stained by antibodies against microglia or macrophages, F4/80, Mac1 or CD45. Immunoelectron microscopy showed that the immunoreaction for NLDC-145 was localized to the sheath and presynaptic terminals of the olfactory nerves. These findings suggest that the sheath and presynaptic terminals of the primary olfactory nerves have some degree of the antigenicity in common with dendritic cells.

Animals↗

PubMed2000

Expression of microglial response factor-1 in microglia and macrophages following cerebral ischemia in the rat.

Microglial response factor-1 is a newly isolated microglial gene, which encodes a Ca(2+) binding protein MRF-1 expressed in microglia and macrophages. We induced 1 h of focal cerebral ischemia or 10 min of global cerebral ischemia in the rat, and investigated the expression of MRF-1 immunoreactivity following ischemia. MRF-1 was present in resting microglia and was upregulated in response to microglial activation. MRF-1 was localized to all the cells of the mononuclear phagocyte system (microglia, monocytes, and perivascular cells) that appeared in the ischemic brain.

Animals↗

PubMed2000

Overexpression of the csk gene suppresses tumor metastasis in vivo.

The non-receptor tyrosine kinase c-Src has been implicated in the development of numerous human cancers. c-Src is activated in colon cancers, particularly in highly metastatic cells, and its overexpression strongly correlates with tumor progression. C-terminal Src kinase (Csk) has been demonstrated to negatively regulate Src family tyrosine kinases through tyrosine phosphorylation at the C-terminal regulatory site (Tyr-527). We report herein that down-regulation of Src kinase activity by adenovirus-mediated csk gene transfer abrogated the highly metastatic phenotype of colon cancer cells. Overexpression of Csk decreased Src tyrosine kinase activity in NL-17 cells, the highly metastatic clone of mouse colon adenocarcinoma 26. Importantly, Csk overexpression in NL-17 cells resulted in significant suppression of in vivo metastasis, without affecting its tumorgenicity. Csk overexpression decreased the invasiveness of NL-17 cells through Matrigel, in vitro reconstituted basement membrane. Gelatin zymography confirmed the decreased protein levels of MMP-2 (gelatinase A) in the supernatants of Csk-overexpressed NL- 17 cells. These results provide a therapeutic basis for interfering with metastasis of colon cancer by csk gene-mediated down-regulation of Src kinase activity.

Adenoviridae↗

PubMed2000

Expressed emotion and psychoeducational intervention for relatives of patients with schizophrenia: a randomized controlled study in Japan.

The benefit of single-family treatment (SFT) in addition to short educational sessions (SES) consisting of multiple-family treatment was investigated. The study design was a randomized controlled study. Subjects were 30 patients suffering from schizophrenia with at least one of their family members showing high expressed emotion (EE) in the Camberwell Family Interview. After the SES, the patients were randomly allocated to two groups: those who received routine individual outpatient treatment and those who received additional SFT and routine treatment. The two groups were followed for 9 months after discharge, and the relapse risks were compared. The relapse risk was lower in the SES+SFT group than in the SES group (23.1% vs. 35.3%). However, the difference was not significant. When high-EE families were classified into those with many critical comments (high-CC) or a high score of emotional overinvolvement (high-EOI), the relapse risk was 0% in the patients living with a high-CC family not only in the SES+SFT group but also in SES group. In the patients living with a high-EOI family, the relapse risk was lower in the SES+SFT group than in the SES group (42.9% vs. 60.0%). These findings suggest that high-EE families should receive at least SES, and additional SFT should be given to families with specific needs.

Adult↗

PubMed2000

The pigmentotropic hormone [His(7)]-corazonin, absent in a Locusta migratoria albino strain, occurs in an albino strain of Schistocerca gregaria.

[His(7)]-corazonin has recently been identified in the corpora cardiaca (CC) of two locust species, the migratory locust, Locusta migratoria and the desert locust, Schistocerca gregaria, as the dark colour inducing neurohormone. Here, we investigate whether [His(7)]-corazonin occurs in the brain-CC axis of a Schistocerca albino strain. From data obtained by immunocytochemistry, injection experiments, chromatographic and mass spectrometric analysis of brain and CC tissues, it could be concluded that an albino strain of S. gregaria from Denmark contains authentic [His(7)]-corazonin. This was unequivocally demonstrated by sequencing the [His(7)]-corazonin-immunoreactive factor in albino Schistocerca brain-CC extracts with ESI-Qq-oa-TOF mass spectrometry. Albinism in this strain is hence not caused by the deficiency of authentic [His(7)]-corazonin in the brain-CC axis, nor by defects in release. Conversely to L. migratoria albinos, injection of [His(7)]-corazonin failed to induce dark pigmentation in Schistocerca albinos. Therefore, albinism in the investigated Schistocerca strain is likely to be situated at the level of the receptor, signal transduction mechanisms or of pigment biosynthesis.

Animals↗

PubMed2000

Dynamical Auger emission induced by multistate vibronic coupling in the core-excited states of the BCl3 molecule.

The Auger emission following the resonant excitation of the BCl3 molecule has been investigated using monochromatized synchrotron radiation. The B 1s excitation to the unoccupied Anti-bonding 4e(') orbital enhances the shoulder structure in the low kinetic energy side of the photoemission from the 2e(') valence bonding orbital. Based on a series of quantum mechanical calculations, this shoulder structure is interpreted as the dynamical Auger emission which reflects the B-Cl stretching nuclear motion and appears as a result of the purely multistate vibronic coupling effect among the Jahn-Teller split B 1s(-1)4e(') E' states and the closely lying B 1s(-1)3a(')(1) A'1 state.

Journal Article↗

PubMed2000

Ghrelin stimulates gastric acid secretion and motility in rats.

Ghrelin, a novel growth-hormone-releasing peptide, was discovered in rat and human stomach tissues. However, its physiological and pharmacological actions in the gastric function remain to be determined. Therefore, we studied the effects of rat ghrelin on gastric functions in urethane-anesthetized rats. Intravenous administrations of rat ghrelin at 0.8 to 20 microgram/kg dose-dependently increased not only gastric acid secretion measured by a lumen-perfused method, but also gastric motility measured by a miniature balloon method. The maximum response in gastric acid secretion was almost equipotent to that of histamine (3 mg/kg, i.v.). Moreover, these actions were abolished by pretreatment with either atropine (1 mg/kg, s.c.) or bilateral cervical vagotomy, but not by a histamine H(2)-receptor antagonist (famotidine, 1 mg/kg, s.c.). These results taken together suggest that ghrelin may play a physiological role in the vagal control of gastric function in rats.

Animals↗

PubMed2000

The diagnostic significance of left auricular thrombus in F344/N rats.

In the process of assessing the main cause of death in F344/N rats from the aging farm of our institute, we have often found left auricular thrombus in autopsy cases of moribund animals. In 319 autopsy cases, 45 were of left auricular thrombus and 44 were accompanied by hematopoietic neoplasms, including overt leukemia and a pre-leukemic condition of leukemia. In cases without splenomegaly, this lesion was found in 13 of 21 animals (61.9%) whereas, in cases with splenomegaly, 31 of 239 were positive for this lesion (13.0%). Thus, left auricular thrombus may be an important macroscopic diagnostic criteria of hematopoietic neoplasms, especially when splenomegaly is absent. Furthermore, this lesion tended to arise in aged animals despite the presence of splenomegaly. These results would therefore greatly contribute to aging science by confirming the health condition of experimental rats and the accuracy of subsequent results.

Journal Article↗

PubMed2000

Hemiparkinsonism associated with the unilateral striatal necrosis: a case report.

We report a patient with hemiparkinsonism associated with unilateral striatal necrosis of the contralateral side. The patient was an 18-year-old woman who had a two-month-history of difficulty in executing skilled movements with her right upper extremity. Neurological examination revealed that she had cogwheel rigidity and bradykinesia in her right upper and lower extremities. MRI revealed a well-delineated low signal intensity in T1-weighted and high signal intensity in T2-weighted images in the region of the putamen on the left side. Her laboratory data were unremarkable and mitochondrial gene mutation studies revealed no abnormality. It is extremely rare to encounter a case of parkinsonism associated with unilateral striatal necrosis.

Journal Article↗

PubMed2000

Effect of norepinephrine receptors on trigeminal rhythm generation in newborn rats.

N-methyl-D,L-aspartate acid and bicuculline are required to enhance the trigeminal rhythmic activities in an in vitro isolated brainstem block preparation. In this study, we analyzed the effect of norepinephrine on the trigeminal neural circuit underlying rhythmic jaw movements. Rhythmic trigeminal activity is observed in brainstem preparations (inferior colliculus to obex) only following blockade of alpha(2)-adrenoceptors with idazoxan. This observation, combined with the inhibition of rhythm by alpha(2)-adrenoceptor agonists suggests endogenous alpha(2)-adrenoceptor mediated inhibition of trigeminal networks. A complex noradrenergic modulation of trigeminal systems is further supported by the prazosin-sensitive potentiation of rhythm by bath application of the alpha(1)-adrenoceptor agonist phenylephrine.

Adrenergic alpha-1 Receptor Agonists↗

PubMed2000

Corticosteroid-responsive diabetes mellitus associated with autoimmune pancreatitis.

Autoimmune pancreatitis, which can be treated with corticosteroid therapy, has the potential to induce diabetes. In a cohort study of 2220 patients with suspected chronic pancreatitis, we found that all four patients with autoimmune chronic pancreatitis also had diabetes. Treatment with prednisolone subsequently improved insulin secretion and glycaemic control in these patients.

Aged↗

PubMed2000

PAL31, a novel nuclear protein, expressed in the developing brain.

We cloned a cDNA encoding a novel protein (PAL31) predominantly expressed in the fetal rat brain by differential display. PAL31 contains leucine-rich repeat domains, a highly acidic region and a putative nuclear localization signal. PAL31 has 50-70% similarity to SSP29, APRIL, LANP, PHAP I, and PP32. Expression of PAL31 mRNA in the brain was high during the fetal period and decreased after birth. Immunohistochemical studies showed that PAL31 is expressed in the entire embryonic brain, whereas in the adult brain its expression is restricted to the subventricular zone where there are neural progenitor cells. It was also revealed that PAL31 is colocalized with PCNA in the nucleus, indicating that the PAL31 expression is developmentally regulated. Considering the primary structure of PAL31 and its spatiotemporal expression pattern, PAL31 is a novel nuclear protein related to the development of the brain through the proliferation of neuronal cells.

Amino Acid Motifs↗