Mitigation of caffeine-induced fetopathy in mice by pretreatment with beta-adrenergic blocking agents.
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In a previous experiment, fetopathic effects of caffeine were significantly reduced by pretreatment with propranolol at dosage levels of 2.5 to 10 mg/kg. The present experiments were undertaeken to investigate the relation between time intervals of propranolol pretreatment and its effect on reducing fetopathy. Furthermore, the effect of timolol, another beta-adrenergic blocking agent, on reducing fetopathy was compared with that of propranolol. Propranolol (5 mg/kg) administered 15, 30 or 60 minutes before caffeine treatment significantly reduced the caffeine-induced fetopathy. The optimal effect was found when propranolol was given 30 minutes before caffine. The reduction in fetopathy by timolol pretreatment was comparable to that of propranolol. The results lend support to the hypothesis that the fetopathic effect of caffeine is linked with released catecholamines in material or fetal issues of mice. (+info)
Essential role of inducible nitric oxide synthase in monophosphoryl lipid A-induced late cardioprotection: evidence from pharmacological inhibition and gene knockout mice.
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BACKGROUND: Monophosphoryl lipid A (MLA), a nontoxic analogue of endotoxin, is a pharmacological agent that is known to have anti-ischemic effects. Mechanisms involved with the cardioprotection are still unclear. A role for inducible nitric oxide synthase (iNOS) was recently proposed. We tested this hypothesis using S-methylisothiourea (SMT), one of the specific pharmacological inhibitors of iNOS, as well as iNOS gene knockout mice. METHODS AND RESULTS: Adult male ICR or B6,129 mice were pretreated with either MLA 35 or 350 microg/kg IP (MLA35 or MLA350) or vehicle 24 hours before global ischemia/reperfusion, which was carried out in a Langendorff isolated perfused heart model (n=8 to 9 per group). Another group of MLA350 mice received SMT 3 mg/kg IP 30 minutes before heart perfusion. Ventricular contractile function and heart rate were not different between the groups during the preischemia and reperfusion periods (P>0.05). Preischemic basal coronary flow was significantly increased in all MLA350 but not MLA35 mice. Myocardial infarct size was reduced significantly, from 26.9+/-2.9% of risk area in vehicle-treated mice to 13.5+/-2.4% in the MLA350 group (mean+/-SEM, P<0.05). This reduction in infarct size was accompanied by augmented nitrite/nitrate accumulation, from 0.23+/-0. 05 nmol/mg protein in the vehicle group to 0.97+/-0.27 nmol/mg protein in MLA350 mice (P<0.01). Infarct size increased significantly, to 22.2+/-2.8% after treatment with SMT in the MLA350 group. Furthermore, MLA350 failed to reduce infarct size in iNOS knockout mice (25.5+/-3.6%). CONCLUSIONS: These results demonstrate a direct association of infarct size reduction with increased NO production with MLA350. An obligatory role for iNOS in mediating the cardioprotective effect induced by MLA was confirmed with the pharmacological inhibition and gene knockout mice. (+info)
Eos: a novel member of the Ikaros gene family expressed predominantly in the developing nervous system.
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We identified a novel member of the Ikaros gene family, which has critical roles in the development of lymphoid lineages. This gene, which we named Eos, was expressed predominantly in the developing central and peripheral nervous system. Eos protein could interact with itself and Ikaros protein through its C-terminal portion in the yeast two hybrid assay. These findings suggested that Eos may have important roles in neural development similarly to the Ikaros family in the development of hemolymphoid tissue. (+info)
Perineuronal nets of proteoglycans in the adult mouse brain, with special reference to their reactions to Gomori's ammoniacal silver and Ehrlich's methylene blue.
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As our previous studies have indicated, many subsets of neurons in the vertebrate brain possess a sulfated proteoglycan surface coat which reacts to cationic iron colloid and aldehyde fuchsin. The present study demonstrated that this surface coat is supravitally stained with Ehrlich's methylene blue, and doubly with this blue and aldehyde fuchsin, a finding suggesting its being identical to Cajal's superficial reticulum (red superficial) and to Golgi's reticular coating (revetement reticulare). The perineuronal surface coat was further stained with Gomori's ammoniacal silver, and doubly with this silver and cationic iron colloid. These neurons with such a proteoglycan surface coat usually expressed cell surface glycoproteins which were labeled with lectin Wisteria floribunda agglutinin. Hyaluronidase digestion did not interfere with this lectin labeling of the glycoproteins, methylene blue and Gomori's ammoniacal silver staining of the surface coat, while it erased the cationic iron colloid and aldehyde fuchsin staining of the surface coat. These findings suggest that the perineuronal proteoglycan surface coat is associated with some additional molecules which are resistant to hyaluronidase digestion and stainable with methylene blue and Gomori's ammoniacal silver. The possibility is suggested that these molecules might represent "ligand proteoglycans" connecting the perineuronal proteoglycans and cell surface glycoproteins. (+info)
Differential display identification of plunc, a novel gene expressed in embryonic palate, nasal epithelium, and adult lung.
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We have identified a novel gene transcript of approximately 1.1 kilobases in length that is expressed in the presumptive nasal epithelium of the mouse embryo. In situ hybridization analysis shows discrete regions of expression associated with the palate, nasal septum, and nasal conchae. This transcript is also expressed strongly in the trachea and bronchi of the adult lung. Screening of a mouse heart cDNA library yielded several overlapping clones to give a continuous sequence of 1113 bases, containing an open reading frame of 278 codons comprising the complete mRNA. No significant homologies with known genes were observed at the nucleotide level; limited amino acid homology with two salivary gland-specific proteins was noted. A search for functionally significant protein motifs revealed consensus sequences for N-glycosylation, protein kinase C and casein kinase phosphorylation, and a leucine zipper. Additionally, we observed a unique amino acid sequence pattern, consisting of the residues Gly-(Leu/Pro/Gln)-(Pro/Leu)-Leu-Pro-Leu, repeated four times near the amino-terminal portion of the protein with two amino acid residues separating the repeats. Based on these observations, we propose that we have identified a new gene, which we call plunc (for palate, lung, and nasal epithelium clone; GenBankTM accession number U69172). (+info)
Morphometric studies of secretory granule formation in mouse pancreatic acinar cells. Dissecting the early structural changes following pilocarpine injection.
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Secretory granule formation in pancreatic acinar cells is known to involve massive membrane flow. In previous studies we have undertaken morphometry of the regranulation mechanism in these cells and in mast cells as a model for cellular membrane movement. In our current work, electron micrographs of pancreatic acinar cells from ICR mice were taken at several time points after extensive degranulation induced by pilocarpine injection in order to investigate the volume changes of rough endoplasmic reticulum (RER), nucleus, mitochondria and autophagosomes. At 2-4 h after stimulation, when the pancreatic cells demonstrated a complete loss of granules, this was accompanied by an increased proportion of autophagosomal activity. This change primarily reflected a greatly increased proportion of profiles retaining autophagic vacuoles containing recognisable cytoplasmic structures such as mitochondria, granule profiles and fragments of RER. The mitochondrial structures reached a significant maximal size 4 h following injection (before degranulation 0.178 +/- 0.028 microm3; at 4 h peak value, 0.535 +/- 0.109 microm3). Nucleus size showed an early volume increase approaching a maximum value 2 h following degranulation. The regranulation span was thus divided into 3 stages. The first was the membrane remodelling stage (0-2 h). During this period the volume of the RER and secretory granules was greatly decreased. At the intermediate stage (2-4 h) a significant increase of the synthesis zone was observed within the nucleus. The volume of the mitochondria was increasing. At the last step, the major finding was a significant granule accumulation in parallel with an active Golgi zone. (+info)
Suppression of antigen-specific Th2 cell-dependent IgM and IgG1 production following norepinephrine depletion in vivo.
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The mechanism by which the Th2 cell-dependent Ab response is modulated by the sympathetic neurotransmitter norepinephrine (NE) was investigated. Our model system used the severe combined immunodeficient (scid) mouse that was depleted of NE with 6-hydroxydopamine before reconstitution with a clone of beta2-adrenergic receptor (beta2AR)neg KLH-specific Th2 cells and resting trinitrophenyl (TNP)-specific beta2ARpos B cells enriched from the spleens of unimmunized mice. Following challenge with TNP-keyhole limpet hemocyanin (KLH), Ab production in these mice was hapten-, carrier-, and allotype-specific as well as MHC restricted. Depletion of NE resulted in a 50-75% suppression of the primary anti-TNP IgM response compared with that of NE-intact controls, while the secondary IgM response returned to control levels. In contrast, both the primary and secondary anti-TNP IgG1 responses were suppressed by 85 and 40%, respectively. Using NE-intact mice exposed to either a betaAR- or alphaAR-selective antagonist, the effect of NE on the Ab response was shown to be mediated by the betaAR. In addition, administration of a beta2AR-selective agonist to NE-depleted mice partially reversed the suppressed Ab response that resulted from NE depletion. Expression of the beta2AR on TNP-specific B cells was confirmed by radioligand binding, immunofluorescence, and cAMP analysis. Also, while splenic histology was comparable in NE-intact and NE-depleted mice before Ag exposure, follicle expansion and germinal center formation were suppressed in NE-depleted mice after Ag exposure. Taken together, these results suggest that NE stimulation of the beta2AR expressed on B cells is necessary for the maintenance of an optimal primary and secondary Th2 cell-dependent Ab response in vivo. (+info)
The effect of prenatal methylmercury exposure on the GSH level and lipid peroxidation in the fetal brain and placenta of mice.
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Effect of prenatal exposure to methylmercury (MeHg) on the glutathione (GSH) levels and lipid peroxidation in the fetal brain was examined. Pregnant ICR mice were injected with 3 mgHg/kg of MeHg on gestational day 12, 13 and 14 (G12-14). On the G14 or G17, the fetal brains were removed and their GSH levels and thiobarbituric acid-reactive substances (TBARS) levels were determined. On the G17, GSH level of MeHg-treated fetal brain was significantly higher than that of the control brain; the TBARS level showed the similar trend but the difference was not significant. These results indicated that the prenatal MeHg treatment disturbed the normal GSH level in the fetal brain and warranted further investigation on the significance of this GSH perturbation. (+info)