Structure of the mouse Stat 3/5 locus: evolution from Drosophila to zebrafish to mouse

Signal transducers and activators of transcription (Stat) are transcription factors that can be activated by many cytokines. While Drosophila contains only one Stat (d-Stat), mammals contain seven, with STATs 3, 5a, and 5b being the closest functional relatives. To understand the evolutionary relationship between d-Stat and vertebrate STATs 3 and 5, we isolated, sequenced, and analyzed the zebrafish Stat3 (z-Stat3) gene and a 500-kb region spanning mouse chromosome 11, 60.5 cM containing three Stat genes (m-Stats). Within this region we identified the genes encoding m-Stats 3, 5a, and 5b, Cnp1, Hcrt/Orexin, Ptrf, GCN5, mDj11, and four new genes. The 5' ends of the m-Stat5a and m-Stat5b genes are juxtaposed to each other, and the 3' ends of the m-Stat3 and Stat5a genes face each other. While the m-Stat5a and m-Stat3 genes have one promoter each, which are active in many tissues, the m-Stat5b gene acquired two distinct promoters. The distal promoter is expressed ubiquitously, and transcription from the proximal promoter is restricted to liver, muscle, and mammary tissue. Through a comparison of exon-intron boundaries from the m-Stat3, m-Stat5a, and m-Stat5b, z-Stat3, and d-Stat genes, we deduced their evolutionary relationship. We propose that the Stat3 and Stat5 lineages are derived from the duplication of a common primordial gene and that d-Stat is a part of the Stat5 lineage.

Characterization of mouse Ire1 alpha: cloning, mRNA localization in the brain and functional analysis in a neural cell line

In yeast, an endoplasmic reticulum (ER)-associated protein, Ire1p, is believed to initiate the unfolded protein response (UPR), that is responsible for protein folding in the ER under stressed conditions. Two mammalian homologs of Ire1p have been identified, Ire1 alpha and Ire1 beta. We have previously reported that familial Alzheimer's disease linked presenilin-1 variants downregulate the signaling pathway of the UPR by affecting the phosphorylation of Ire1 alpha. In the present study, we cloned the mouse homolog of Ire1 alpha for generating genetically modified mice. Ire1 alpha was ubiquitously expressed in all mouse tissues examined, and was expressed preferentially in neuronal cells in mouse brain. This led us to investigate the effects of the downregulation of the UPR on the survival of neuronal cells under conditions of ER stress. Morphological and biochemical studies using a dominant-negative form of mouse Ire1 alpha have revealed that cell death caused by ER stress can be attributed to apoptosis, and that the downregulation of the UPR enhances the apoptotic process in the mouse neuroblastoma cell line, Neuro2a. Our results indicate that genetically modified mice such as transgenic mice with a dominant-negative form of Ire1 alpha might provide further understanding of the pathogenic mechanisms of Alzheimer's disease and other neurodegenerative disorders.

Improvement in Development of Porcine Embryos Reconstituted with Cells from Blastocyst-Derived Cell Lines and Enucleated Oocytes by Optimization of Reconstruction Methods

The present study was conducted to establish the most suitable system for producing porcine reconstructed embryos by transferring cells from blastocyst-derived cell lines into enucleated oocytes. When the cells were fused to preactivated metaphase II oocytes, or the cells and arrested metaphase II oocytes were fused in medium without CaCl(2) and MgSO(4), the percentages (43-53%) of fused embryos were significantly lower than those (72-79%) produced by fusing the cells to arrested metaphase II oocytes in medium containing CaCl(2) and MgSO(4). High productive efficiency (7%) of blastocysts was obtained when reconstituted embryos produced by the last method were activated again at 3 hours after fusion (F/A --> Activation). Pronuclear formation was observed in 80-91% of the reconstructed embryos produced by F/A --> Activation, with no significant differences between different culture periods in the medium containing cytochalasin B. When cultured in the medium containing cytochalasin B for 0-1 h, almost all (83-85%) the embryos had one pronucleus and one polar body. However, the number of embryos with two pronuclei and no polar bodies was increased significantly by culturing in the medium containing cytochalasin B for 2-4 h. The cleavage rate (34-48%) of reconstructed embryos was not affected by the presence of cytochalasin B for 2 h after activation. However, the percentage of embryos that developed to the blastocyst stage was significantly higher in the presence (23%) than absence (5%) of cytochalasin B. The results indicate that F/A --> Activation and cytochalasin B treatment are effective for the production of porcine embryos reconstituted with cells from blastocyst-derived cell lines and enucleated oocytes.

Inhibitory effect of TAS-301, a new synthesized constrictive remodeling regulator, on renarrowing after balloon overstretch injury of porcine coronary artery

The purpose of this study was to determine the efficacy and the possible mechanism of action of a recently synthesized drug, TAS-301 [3-bis(4-methoxyphenyl)methylene-2-indolinone], on stenosis after balloon overstretch injury of porcine arteries. We measured the diameter of vessels by angiography and conducted histological analysis. The oral administration of TAS-301 kept dilated the angiographic luminal diameter of injured segment 4 weeks after overstretch injury and reduced calculated stenosis ratio in a dose-dependent manner, significantly reducing it at doses of 30 and 100 mg/kg. Histopathological analysis showed that TAS-301 significantly reduced the adventitial area at doses of 30 and 100 mg/kg with moderate reduction of the neointimal area, resulting in the larger residual lumen. In an in vitro assay, TAS-301 dose dependently inhibited the proliferation of adventitial fibroblasts stimulated by basic fibroblast growth factor or transforming growth factor-beta(1). In addition, the drug reduced adventitial fibroblast-mediated three-dimensional collagen gel contraction. These findings indicate that TAS-301, the first compound developed for targeting the constrictive remodeling, showed a high inhibitory potency on coronary artery stenosis of micropigs after injury, mainly due to inhibition of adventitial fibroblast proliferation and of the contractile ability of myofibroblasts. Our results suggest the strong possibility that TAS-301 may be efficacious for prevention of restenosis after angioplasty and the need to examine the therapeutic usefulness of this drug in clinical trials.

Enzyme-linked immunosorbent assays of canine apolipoproteins B-100 and A-I

An enzyme-linked immunosorbent assay (ELISA) for canine blood apolipoprotein (apo) B-100 and A-I was developed. The working range for the assay was 1.8 to 28.7 ng/well for apoB-100 and it was 50 to 410 ng/well for apoA-I. The intra- and inter-assay coefficients of variation for the assay for apoB-100 were 5.4 and 6.9%, respectively, and for apoA-I they were 5.8 and 10.6%, respectively. The average concentrations of apoB-100 and A-I in 25 beagles (males, aged 3-4 years) were 0.084 +/- 0.028 (mean +/- SD) mg/ ml and 6.29 +/- 1.55 mg/ml, respectively. The ratios of canine (C) apoB-100 to CapoA-I were 1.41 +/- 0.58%. The respective concentrations in one case of hyperlipidemia with systemic atherosclerosis were 0.454 mg/ml and 11.28 mg/ml (a ratio of 4.03%). These values were larger than those of the controls. These results suggest that the measurements of CapoB-100 and A-I concentrations by this newly developed ELISA are helpful for diagnosis of lipidosis.

Effects of magnesium and its mechanism on the incidence of reperfusion arrhythmias following severe ischemia in isolated rat hearts

Magnesium sulfate (Mg) has been widely used for the treatment of ventricular arrhythmias (VF) in patients with coronary artery disease. However, the mechanisms of prevention on the incidence of VF have not been defined. The aim of study was to investigate the role of Mg in the prevention of VF and the mechanism of those effects. Series 1 studied antiarrhythmic effects on VF. Isolated rat hearts were perfused in the working heart mode with Krebs'-Henseleit bicarbonate buffer (KHB). Whole heart ischemia was induced by a one-way ball valve with 300 beats/min electrical pacing for 10 minutes followed by 20 minutes of aerobic reperfusion. After control perfusion, Mg was added from 5 minutes before ischemia and was continued to the end of ischemia (1.2 mM for the control group and 2.4, 3.6, 4.8, and 9.6 mM for the study animals) or during reperfusion (3.6 mM). Left ventricular pressure, aortic flow, and ECG were monitored. Series 2 studied the effect of Mg on [Ca2+]i. Hearts were perfused by the Langendorff mode and were loaded with 4 microM of Fura 2/AM as a [Ca2+]i indicator. Ca2+ was monitored using the ratio of Fura-2 fluorescence intensity at excitation wavelengths of 340 and 380 nm. The hearts were subjected to a 20 minutes of low-flow ischemia followed by 20 minutes of aerobic reperfusion. Then 3.6 mM Mg was added to the KHB medium during ischemia. The duration of VF was significantly suppressed in the 2.4, 3.6, and 4.8 mM/L Mg-added groups (472 +/- 173, 779 +/- 159, and 525 +/- 202 second, respectively) when compared with the control group (1200 seconds). Magnesium sulfate suppressed the fluorescence ratio of the diastolic Ca2+ level at the end of 20 minutes of ischemia from 40.5 +/- 3.6% to 9.0 +/- 1.0% (P < 0.05 vs. control hearts). These results suggested that Mg had a beneficial effect on VF and that the optimal Mg concentration was between 2.4 and 4.8 mM. The mechanism of the prevention of VF by Mg could be through the inhibition of [Ca2+]i retention during ischemia.

TAS-301 blocks receptor-operated calcium influx and inhibits rat vascular smooth muscle cell proliferation induced by basic fibroblast growth factor and platelet-derived growth factor

The purpose of this study was to determine the effect of a recently synthesized drug, TAS-301 [3-bis(4-methoxyphenyl)methylene-2-indolinone], on vascular smooth muscle cell (VSMC) proliferation and the intracellular signal transduction pathways involved in VSMC proliferation. In an in vitro assay, TAS-301 inhibited the proliferation of rat VSMCs stimulated by platelet-derived growth factor (PDGF)-BB, basic fibroblast growth factor, or 2% fetal bovine serum in a concentration-dependent manner. TAS-301 dose-dependently inhibited the PDGF-induced Ca2+ influx; the concentration for the inhibition of Ca2+ influx was nearly identical to that for inhibition of VSMC proliferation. The Ca2+ influx induced by PDGF was also attenuated by NiCl2 but not by nifedipine, suggesting that PDGF-induced Ca2+ influx would be mediated by some non-voltage-dependent mechanisms. Furthermore, TAS-301 inhibited PDGF-induced activation of protein kinase C (PKC) and the phorbol 12-myristate 13-acetate-mediated induction of activator protein 1 (AP-1) in a concentration-dependent manner. These findings indicate that TAS-301 inhibited the proliferation of VSMCs by blocking voltage-independent Ca2+ influx and downstream signals such as the Ca2+/PKC signaling pathway, leading to AP-1 induction.

[A patient with motor neuron syndrome clinically similar to amyotrophic lateral sclerosis, presenting spontaneous recovery]

We report a patient with motor neuron syndrome similar to amyotrophic lateral sclerosis (ALS) and with spontaneous recovery. At the age 40, the woman developed progressive muscular weakness, atrophy and fasciculation in extremities. She also noted a dyspnea, tongue atrophy and dysphagia. A neurological examination 6 months after onset revealed i) a tongue atrophy and fasciculation, ii) diffuse muscule weakness and atrophy in face, neck and extremities, and iii) marked hyperreflexia in the four limbs and bilateral Babinski reflex, but iv) neither sensory disturbance nor ophthalmoplegia. Electromyogram (EMG) detected such denervation potentials as fibrillation potentials, fasciculation potentials, positive sharp waves and polyphasic or giant MUPs diffusely in the limb muscles. Peripheral nerve conduction study detected neither conduction block nor delay. Thus, she was diagnosed as suffering from ALS. However, since approximate 1 year after onset, her muscle weakness has gradually been getting better. Simultaneously, the dyspnea and dysphagia gradually improved. Two years after onset, an EMG examination detected chronic denervation potentials in the left musculus sternocleidomastoideus and a few on-going denervation potentials in the left musculus extensor carpi radialis, but no denervation potentials in other limb muscles. Fasciculation potentials were found in tongue muscles. Thus, the present case was thought to have a reversible motor neuron syndrome clinically quite similar to ALS. A mild increase in IgE (346 U/ml) and a low-titer IgM-class anti-GM1 antibody were found in her serum though its pathological significance was uncertain. Any immunological aberrance may account for the pathogenesis. It should be noted that clinically diagnosed cases of ALS may rarely recover spontaneously.

A Japanese patient with frontotemporal dementia and parkinsonism by a tau P301S mutation

The authors report a patient carrying a missense mutation in exon 10 of tau that causes a substitution at codon 301 (P301S). Although the patient shares the rapidly progressive frontotemporal dementia of the other reported pedigrees with P301S, the clinical phenotype is unique in that parkinsonism was a major symptom in the early stage and because behavioral symptoms with dementia became prominent 2 years after the onset of the disease. This study substantiates the notion that tau mutations at codon 301 can show various phenotypes.

Spinal intradural perimedullary arteriovenous fistula with varix in infant

A rare occurrence of type IV spinal arteriovenous malformation (intradural perimedullary arteriovenous fistula) is described in an 18-month-old boy initially misdiagnosed with Guillain-Barré syndrome. An intramedullary mixed-intensity mass lesion at Th1 was demonstrated by magnetic resonance imaging together with flow voids over the dorsal aspect of the swollen spinal cord. Angiography demonstrated an intradural perimedullary arteriovenous fistula including an intraparenchymal vascular pocket. After partial embolisation of the posterior spinal arteries through the left intercostal-radicular artery, the arteriovenous fistula was removed completely together with an organised haematoma. The fistula directly opened into a vascular pocket, which was confirmed pathologically to be a varix. The postoperative course was uneventful, and the patient resumed ambulation within 4 months. The case, subclassifiable as a type IVb spinal perimedullary AVF, was unique given its location and the patient's age at presentation.

Dechlorination of hexachlorobiphenyl by using potassium-sodium alloy

2,2',4,4',5,5'-Hexachlorobiphenyl (HCB) was dechlorinated with potassium-sodium (K-Na) alloy under an inert gas atmosphere. Solvent effect was observed in the reaction. Dechlorination yields in benzene and cyclohexane were 99.9998%, and 99.99996%, respectively. The reaction was exothermic and proceeded at room temperature. In benzene, trace amounts of polychlorinated biphenyls (PCBs) as products by stepwise dechlorination and polychlorinated quarterphenyls as product of Wurtz-Fittig reaction were detected as reaction intermediate. Reaction products were biphenyl, cyclohexylbenzene, and dicyclohexyl. In cyclohexane, there were no products of Wurtz-Fittig reaction. Dechlorination at para-position preferred to that at ortho-position, judging from analysis of PCBs as intermediates of stepwise dechlorination.

A new practical strategy for the synthesis of long-chain phosphopeptide

A new practical strategy has been developed for the synthesis of long-chain phosphopeptide. Both the 2-chlorobenzyloxycarbonyl (CIZ) group for Lys and methyl (Me) for phosphoamino acids remained intact, while other commonly used side-chain protecting groups were cleaved quantitatively, during the reaction using a highly acidic trifluoromethanesulfonic acid (TFMSA)-based reagent system (High TFMSA: TFMSA-TFA-m-cresol=1:9:1, v/v). Selective deprotection of the CIZ and Me group-containing protected phosphopeptide resin with the High TFMSA gave a partially protected phosphopeptide fragment suitable for thioester-mediated fragment condensation. A deprotection protocol of the 9-fluorenylmethyloxycarbonyl (Fmoc) group, which evades significant side reaction toward the protected phosphoamino acid, was also developed. These two new findings enabled us to synthesize long-chain phosphopeptide via thioester-mediated fragment condensation.

Ebp2p, yeast homologue of a human protein that interacts with Epstein-Barr virus nuclear antigen 1, is required for pre-rRNA processing and ribosomal subunit assembly

BACKGROUND

A defect in the secretory pathway causes the transcriptional repression of both rRNA and ribosomal protein genes in Saccharomyces cerevisiae, suggesting a coupling of ribosome synthesis and plasma membrane synthesis. Rrs1p, an essential nuclear protein, is required for the secretory response.

RESULTS

EBP2, encoding the yeast homologue of a human protein that interacts with Epstein-Barr virus Nuclear Antigen 1, was cloned in a two-hybrid screen using RRS1 as a bait. The rrs1-1 mutation, which produces Rrs1p without the C-terminal half and causes a defect in the secretory response, almost abolished the interaction with Ebp2p. Ebp2p is essential for growth and is mainly localized in the nucleolus. The effects of Ebp2p depletion on ribosome biogenesis is quite similar to that of Rrs1p depletion; in the Ebp2p-depleted cells, the rate of pre-rRNA processing is slower, and significantly less mature 25S rRNA is produced compared to those in wild-type cells. The polysome pattern indicates that Ebp2p-depletion causes a decrease of 80S monosomes and polysomes, an accumulation of 40S subunits, and the appearance of half-mer polysomes.

CONCLUSIONS

Ebp2p is required for the maturation of 25S rRNA and 60S subunit assembly. Ebp2p may be one of the target proteins of Rrs1p for executing the signal to regulate ribosome biogenesis.

Cell adhesive sequences in mouse laminin beta1 chain

Laminin-1, a major component of the basement membrane, consists of three different chains, alpha1, beta1, and gamma1. We sought to identify cell adhesive sequences from the mouse laminin beta1 chain by testing HT-1080 fibrosarcoma and B16-F10 melanoma cells for binding to 187 overlapping synthetic peptides which covered the entire chain. Fourteen peptides showed cell adhesive activities with either peptide-conjugated Sepharose beads or peptide-coated plates or both. Additional cells, including neuronal, endothelial, and salivary gland cells, showed biological responses in a cell type-specific manner. B-7, B-133, and B-160 showed the most potent cell attachment. Cell binding on three peptides (B-34, B-133, and B-160) was inhibited by EDTA. Cell adhesion to 11 of the 12 active peptides was inhibited to varying degrees by heparin. Of the 17 active peptides identified in the laminin beta1 chain in this and other studies, 8 are clustered on the amino terminal globular domain, suggesting a possible important role in cell binding for this domain that may be multifunctional. These data demonstrate that the laminin beta1 chain has multiple active sites for cell adhesion, some of which are cell-type specific.

Establishment of a porcine cell line from in vitro-produced blastocysts and transfer of the cells into enucleated oocytes

The present study was conducted to establish a porcine cell line from blastocysts produced in vitro and to examine the developmental ability of nuclear transfer embryos reconstituted with the cells and enucleated mature oocytes. When hatched blastocysts were cultured in Dulbecco's modified Eagle's medium with supplements, no colonies of embryo-derived cells were observed. In contrast, 56% of embryos that were attached to feeder layers of STO cells formed colonies in NCSU-23 with supplements. When the colonies were subcultured in the absence of feeder cells, a cell line with an epithelial-like cell morphology was obtained. This cell morphology was stable up to at least passage 30. Although no fused embryos were observed when a pulse of 100 V/mm was applied, the fusion rate increased significantly at 150 V/mm (28%) and 200 V/mm (64%). At 200 V/mm, 39% of fused embryos cleaved, but no embryos developed beyond the 3-cell stage. When cocultured with electro-activated oocytes, percentages of reconstructed embryos cleaved (65%) and developed to the 4-cell stage (23%) were significantly higher than percentages for those (cleavage: 38%; 4-cell stage: 3%) in the absence of activated oocytes. At 7 days after culture, one reconstructed embryo successfully developed to the blastocyst stage in the presence of activated oocytes. When green fluorescent protein-expressing cells and enucleated oocytes were fused and the fused embryos were cultured with electro-activated oocytes, 3 of 102 reconstructed embryos developed to the blastocyst stage. All of the blastocysts were positive for fluorescent green under ultraviolet light. The results of the present study indicate that a porcine cell line can be established from the hatched blastocyst and maintained in vitro for a long period, and that reconstructed embryos obtained by transferring the blastocyst-derived cells into enucleated oocytes have the ability to develop to the blastocyst stage in vitro.

Molecular cloning of a novel membrane glycoprotein, pal, specifically expressed in photoreceptor cells of the retina and containing leucine-rich repeat

We have isolated a novel retina-specific gene in a screen for genes of which expression is not apparent neonatally in rat retina but is abundant postnatally on day 14 (P14). This gene, named Pal, encodes a putative type I transmembrane protein containing five leucine-rich repeats (LRRs), a single C2-type Ig-like domain, and a single fibronectin type III domain and is considered to be a new member of the LRR and Ig superfamily. No expression of Pal was found in rat retina at P1, but it was detected at P7 and markedly increased with subsequent development. These expression patterns of Pal appeared to be correlated with the development of the photoreceptor outer segments, because in the adult rat retina it was specifically localized in these segments. Ultrastructually, Pal immunoreactivity was distributed diffusely on the disk membrane in the lamellar regions. On the basis of its structural features and localization pattern, Pal may act as a receptor for a certain trophic factor or for an adhesion molecule participating in morphogenesis. The human homolog of Pal was mapped to chromosome 10q23.2-23.3 using fluorescence in situ hybridization.

Regulatory mechanisms of TRAF2-mediated signal transduction by Bcl10, a MALT lymphoma-associated protein

To elucidate the function of Bcl10, recently cloned as an apoptosis-associated gene mutated in MALT lymphoma, we identified its binding partner TRAF2, which mediates signaling via tumor necrosis factor receptors. In mammalian cells, low levels of Bcl10 expression promoted the binding of TRAF2 and c-IAPs. Conversely, excessive expression inhibited complex formation. Overexpressed Bcl10 reduced c-Jun N-terminal kinase activation and induced nuclear factor kappaB activation downstream of TRAF2. To determine whether overexpression of Bcl10 could perturb the regulation of apoptosis in vivo, we generated Bcl10 transgenic mice. In these transgenic mice, atrophy of the thymus and spleen was observed at postnatal stages. The morphological changes in these tissues were caused by acceleration of apoptosis in T cells and B cells. The phenotype of Bcl10 transgenic mice was similar to that of TRAF2-deficient mice reported previously, indicating that excessive expression of Bcl10 might deplete the TRAF2 function. In contrast, in the other organs such as the brain, where Bcl10 was expressed at high levels, no apoptosis was detected. The altered sensitivities to overexpressed Bcl10 may have been due to differences in signal responses to Bcl10 among cell types. Thus, Bcl10 was suggested to play crucial roles in the modulation of apoptosis associated with TRAF2.

RRS1, a conserved essential gene, encodes a novel regulatory protein required for ribosome biogenesis in Saccharomyces cerevisiae

A secretory defect causes specific and significant transcriptional repression of both ribosomal protein and rRNA genes (K. Mizuta and J. R. Warner, Mol. Cell. Biol. 14:2493-2502, 1994), suggesting the coupling of plasma membrane and ribosome syntheses. In order to elucidate the molecular mechanism of the signaling pathway, we isolated a cold-sensitive mutant with a mutation in a gene termed RRS1 (regulator of ribosome synthesis), which appeared to be defective in the signaling pathway. The rrs1-1 mutation greatly reduced transcriptional repression of both rRNA and ribosomal protein genes that is caused by a secretory defect. RRS1 is a novel, essential gene encoding a nuclear protein of 203 amino acid residues that is conserved in eukaryotes. A conditional rrs1-null mutant was constructed by placing RRS1 under the control of the GAL1 promoter. Rrs1p depletion caused defects in processing of pre-rRNA and assembly of ribosomal subunits.

Presenilin-1 mutations downregulate the signalling pathway of the unfolded-protein response

Missense mutations in the human presenilin-1 (PS1) gene, which is found on chromosome 14, cause early-onset familial Alzheimer's disease (FAD). FAD-linked PS1 variants alter proteolytic processing of the amyloid precursor protein and cause an increase in vulnerability to apoptosis induced by various cell stresses. However, the mechanisms responsible for these phenomena are not clear. Here we report that mutations in PS1 affect the unfolded-protein response (UPR), which responds to the increased amount of unfolded proteins that accumulate in the endoplasmic reticulum (ER) under conditions that cause ER stress. PS1 mutations also lead to decreased expression of GRP78/Bip, a molecular chaperone, present in the ER, that can enable protein folding. Interestingly, GRP78 levels are reduced in the brains of Alzheimer's disease patients. The downregulation of UPR signalling by PS1 mutations is caused by disturbed function of IRE1, which is the proximal sensor of conditions in the ER lumen. Overexpression of GRP78 in neuroblastoma cells bearing PS1 mutants almost completely restores resistance to ER stress to the level of cells expressing wild-type PS1. These results show that mutations in PS1 may increase vulnerability to ER stress by altering the UPR signalling pathway.

Construction of Epstein-Barr virus-based expression vector containing mini-oriP

Epstein-Barr virus (EBV)-based vectors are extrachromosomal vectors carrying a replicational origin, oriP (about 2200 bp) and a replication initiation factor (EBNA-1) which are sufficient for autonomous replication. Because one disadvantage of these vectors is their large sizes, we examined the effect of partial deletion of oriP on the effectiveness of the EBV-based vectors, using an enhanced green fluorescent protein (EGFP) as a reporter to monitor gene expression. Results indicated that 954 bp-deleted mini-oriP is useful in primate cells since the vector showed high efficiency of stable transfection, a high ratio of EGFP-positive cells, and high recovery of intact plasmid DNA from transfected cells.

Distinctions between microglial cells and peripheral macrophages with regard to adhesive activities and morphology

Activated microglial cells and peripheral macrophages are hardly distinguishable from the viewpoints of morphology and function. There are various immunological markers common to both microglial cells and peripheral macrophages. In the present study, however, we found that microglial cells have distinct characters in terms of adhesion and morphology. By using a "rheoscope," that is an apparatus to rheologically measure the strength of cell adhesion to substrates, rat microglial cells were found to attach to polystyrene dishes much more weakly than alveolar and peritoneal macrophages. Interferon-gamma (IFNgamma) strengthened the adhesion of alveolar and peritoneal macrophages, whereas it weakened that of microglial cells. Morphological changes of microglial cells induced by IFNgamma were also different from those of peripheral macrophages. Furthermore, alveolar and peritoneal macrophages produced NO in response to IFNgamma, while microglial cells did not. When cultured on astrocyte-derived extracellular matrix (AsECM) in serum-free medium, only microglial cells extended multiple ramified processes. Conversely, alveolar and peritoneal macrophages on AsECM shrunk their ruffling membrane and rounded up. These distinctions between microglial cells and macrophages may reflect differences in cell lineages as well as environments in which individual cells reside.

Superovulation of immature hypothyroid rdw rats by thyroxine therapy and the development of eggs after in vitro fertilization

The aim of this study was to examine the effect of thyroxine on ovulation in immature rdw rats and the fertilization and development of the eggs. Serum thyroxine concentrations at 30 days of age were significantly lower in rdw rats than in normal rats (P < 0.001), and greatly increased after thyroxine replacement therapy (P < 0.001). Although few eggs (1-5 +/- 1-2) were obtained from immature rdw rats treated with gonadotrophins alone, females treated with gonadotrophins and thyroxine ovulated significantly more eggs (85 +/- 5). As a control, normal littermates ovulated 21-45 eggs when treated with gonadotrophins alone, and 68 eggs when administered with gonadotrophins and thyroxine. Of the eggs collected from rdw rats treated with gonadotrophins and thyroxine, and inseminated with spermatozoa from mature F1 males, 98% were penetrated and in almost all (99%) of these eggs, male and female pronuclei formed. Forty-seven per cent of the pronuclear eggs developed to the blastocyst stage in vitro. After transfer to recipients, 21% (14/66) of one-cell and 22% (8/37) of two-cell embryos developed to offspring, and 62% (8/13) of pups were of rdw/rdw genotype. The average body weight (6.9 versus 7.8 g) of offspring derived from one-cell embryos was lower than that for two-cell embryos. The morulae and blastocysts did not develop to term, although 41% implanted in the uterine horns of recipients. In conclusion, in immature rdw rats, superovulation was induced by gonadotrophins combined with thyroxine therapy and the superovulated oocytes were fertilized and developed in vitro and developed to term after embryo transfer.

Effect of hyaluronic acid on the development of porcine 1-cell embryos produced by a conventional or new in vitro maturation/fertilization system

In pigs, it is difficult to produce normal fertilized embryos from immature oocytes in vitro. However, a new maturation/fertilization system in which the percentage of normal fertilized embryos is comparatively high has been developed recently. In the present study, porcine 1-cell embryos were produced both by a conventional and a new system and then cultured in NCSU-23 supplemented with hyaluronic acid at various concentrations. In the conventional system, the percentage of oocytes with monospermic penetration and 1 male pronucleus and 1 female pronucleus was only 6%. At 144 h after insemination, the percentage (5%) of embryos developing to the blastocyst stage in medium supplemented with 0.5 mg/mL hyaluronic acid was significantly (P<0.05) higher than that (2%) in medium without hyaluronic acid. When oocytes were matured and inseminated using the new system, monospermic penetration and the formation of 1 male and 1 female pronucleus were observed in 69% of the penetrated oocytes. However, blastocyst formation (8 to 14%) at 144 h after insemination was not affected by the concentration (0 to 1.0 mg/mL) of hyaluronic acid. These results indicate that the effect of hyaluronic acid on the development of in vitro-produced porcine embryos varies with the conditions of oocyte maturation and fertilization.