Anionic copolymerization of β-lactones in correlation with the mode of fission. studies on the syntheses of aliphatic polyesters. XI

The copolymerization behavior of β-propiolactone (PL) and α.α-bischloromethyl β-propiolactone (α-BCPL) is correlated with the mode of fission. With sodium acetate as catalyst, the formation of β-acetoxy propionic acid at the initiation reaction was observed and α-BCPL was more than five times as reactive as PL in copolymerization. Thus propagation by carboxylate anion through alkyl-oxygen fission was presumed in the case of pyridine and the acetate of Na, Li, and Mg as catalyst. On the other hand, the formation of ethyl β-hydroxy propionate and the decreased reactivity of α-BCPL in copolymerization was observed with magnesium and aluminum ethoxide as catalyst. In the case of the ethoxide of Na, Li, and Al, and Et₂Mg or Et₃Al as catalyst, propagation by alkoxide anions through acyl-oxygen fission of the coordinated lactones was presumed.     

Anionic polymerization of fluorine-containing vinyl monomers, 6. Polymerizations of fluoroalkyl acrylates and methacrylates initiated by organoaluminium compounds

The anionic polymerizations of 2,2,2-trifluoroethyl acrylate ( 1a ), 2,2,2-trifluoroethyl methacrylate ( 1b ), 2,2,2-trifluoro-1-trifluoromethylethyl acrylate ( 2a ), and 2,2,2-trifluoro-1-trifluoromethylethyl methacrylate ( 2b ) were examined with triethylaluminium and diethylaluminium active methylene chelate compounds as initiators. 2b was polymerized with triethylaluminium. Diethyl(ethyl cyanoacetato)aluminium was found to produce polymers of 1a and 1b . Diethyl(acetylacetonato)aluminium and diethyl (dimethyl malonato)aluminium, however, show low reactivity towards these four monomers. The resulting polymers show unimodal molecular weight distribution with number-average molecular weights of 10⁴?10⁵, measured by GPC. The initiation reaction and the copolymerization reactivity with styrene support the anionic polymerization mechanism.     

Contribution of BCAP to maintenance of mature B cells through c-Rel

Mice deficient in the B cell adaptor for phosphoinositide 3-kinase (BCAP) have reduced numbers of mature B lymphocytes, which show defects in cell survival and proliferation. We found here that the NF-kappa B (Rel) pathway was impaired in BCAP-deficient mature B cells and that NF-kappa B target genes, indispensable for cell survival and division, were not induced in response to B cell receptor (BCR) stimulation. Among the NF-kappa B (Rel) family, expression of c-Rel was specifically reduced in BCAP-deficient B cells. Retrovirus-mediated reintroduction of c-Rel restored the pool size of immunoglobulin (Ig)M(lo)IgD(hi) mature B cells in the spleen as well as proliferative responses to BCR stimulation. These results indicate BCAP is essential in the maintenance of mature B cells through functional coupling with c-Rel.     

Difference in cytokine production and cell activation between adenoidal lymphocytes and peripheral blood lymphocytes of children with otitis media

We evaluated the immunological potential of adenoidal lymphocytes from children with recurrent otitis media. Interleukin-4 release and CD69 expression were lower in adenoidal lymphocytes than in peripheral blood lymphocytes (PBL). Our results suggest that there may be a difference between the immunological potential of adenoidal lymphocytes and that of PBL in children with otitis.     

Mechanomyography of the human quadriceps muscle during incremental cycle ergometry

The mechanical activity of the human quadriceps muscle during maximal incremental cycle ergometry was investigated by mechanomyography (MMG). MMG and surface electromyography (EMG) recordings of vastus lateralis muscle activity were obtained from nine males. Cycle ergometry was performed at 60?rev/min and work load was incremented step wise by 20?W (3.2?Nm) every minute until volitional fatigue. The mean amplitudes of MMG (mMMG) and EMG (mEMG) during the contraction phase were calculated from the last six contractions in each load. The duration, load and work rate of exercise at exhaustion were 13.3 (1.6)?min, 44.1 (5.5)?Nm, 276.7 (34.7)?W, respectively. A linear relationship between mMMG and load was evident in each subject (r?=?0.868–0.995), while mEMG seemed to dissociate as the load became greater. In the grouped mean data, mMMG was linearly related to load whether aligned to the absolute (r?=?0.995) or maximal (r?=?0.995) load. Involvement of the noise component was further investigated by studying passive cycling by four subjects. Pedals were rotated passively for the first half of each stage (PAS) and the subject then pushed the pedals for the second half (ACT). In the lighter load region, the mMMG of ACT was as small as that of PAS. However, the change in the mMMG of PAS was very small compared with that of ACT. In conclusion, this study demonstrates a linear relationship between the mMMG of the quadriceps muscle and work load during maximal incremental cycle ergometry. The effect of movement noise was thought to be small and stable.     

B cell development is perturbed in bone marrow from c-fos/v-jun doubly transgenic mice

c-fos and c-jun gene products form a heterodimeric complex (AP-1)that regulates target gene expression by binding to a specificDNA sequence motif. In order to study a role of AP-1 (Fos/Jun)in growth and differentiation of immature B lineage cells, wehave established and mated two independent transgenic mice carryingthe mouse c-fos gene or the viral v-Jun gene fused to the H-2Kpromoter. IL-7 dependent bone marrow cell culture from doublytransgenic (H2-fos/jun) mice demonstrated severe delay of earlyB cell development. Proliferation of pre-B cells in the freshbone marrow from HZ-fos/jun mice to IL-7 stimulation was verylow. These results suggest that the deregulated production ofAP-1 perturbs IL-7 mediated proliferation and differentiationof immature B cells.     

Suppressive effects of Sairei-to on monoclonal antibody 1–22–3-induced glomerulonephritis: Analysis of effective components

The effects of treditional Chinese medlclne (Salrel-to) on experimental glomerulonephritls Induced In rats by monodonal antibody (mAb) 1–22–3 lnjectlon was examined. The level of proteinuria in the Sairel-to-treated group was significantly lower than that In the PBS treated group. This suppressive effect was caused by the major component of Sealer-to, Syo-salko-to but not by another component, Gorel-san. The suppressive effect of Syo-salko-to was Identified In Its components ( Bupleuri radix, Pindilae tuber and Zingibers rhizoma ), but not In the other combined components ( Ginseng radix and Zizyphl fructus ). Further study weeled that the suppressive effects of the combined components were mainly derived from Bupleuri radix . It was demonstrated that the actual active Ingredient is probably Salkosaponin-d. Light microscopy revealed that Sairel-to and Its effective components suppressed the proliferation of mesanglal cells and mesanglal matrix expansion. Semi quantitative morphological studies of glomerular lesions on the eighth day showed that Syo-salko-to and Its combined components ( Bupleuri radix, Zinglberis rhizoma and Pinelliae tuber ) suppressed mesanglal matrix expansion significantly compared with phosphate-buffered saline control groups (matrix score: 28.0±19.1 vs 102.3±14.1; 30.9±30.1 vs 102.3±14.1, p<0.005, respectively). It was concluded that Salkosaponln-d, as well as Bupleuri radix , Syo-salko-to and Sairel-to can suppress proteinurla and morphological changes In the rat glomerulonephritls model Induced by mAb 1–22–3.     

Cloning of TPA-inducible early (TIE) genes by differential hybridization using TPA-Nonresponsive variant of mouse 3T3-L1 cells

The tumor promoter 12-O -tetradecanoylphorbol-13-acetate (TPA) induces DNA synthesis in quiescent 3T3-L1 cells but not in its variant VT-1 cells. A gt10 cDNA library was constructed using poly(A)⁺ RNA from 3T3-L1 cells that were stimulated by TPA for 20 min. Radioactive cDNA probes were prepared from mRNAs of TPA-treated 3 T3-L1 and VT-1 cells and used for screening of the 3T3-L1 cDNA library by differential hybridization. Nine of 6000 phage plaques hybridized only to the 3T3-L1 cDNA probe. Analysis of the nucleotide sequence of five of these clones indicated a high degree of homology with human or mouse type I and type III collagen genes. Three other independent clones showed no homology with any known DNA sequences. These isolated clones of TPA-inducible early (TIE) genes may be useful to study the signal transduction pathway of phorbol esters.     

Excitatory GABAergic synaptic potentials in the mesencephalic trigeminal nucleus of adult rat in vitro

The mesencephalic trigeminal nucleus (MesV) contains the somata of primary afferent neurons innervating masticatory muscle spindles and the periodontal membrane. MesV afferent somata are unique in receiving synaptic inputs. Intracellular recordings in coronal pontine slices from adult rats were made from MesV neurons identified by having Cs-sensitive inward rectification and pseudounipolar morphology. Stimuli near the MesV evoked either a cluster of action potentials superimposed on a postsynaptic potential (PSP) or an antidromic spike at resting membrane potential (RMP). Membrane hyperpolarization revealed that each cluster of action potentials consisted of an antidromic spike and a subsequent PSP. Evoked PSPs in slices and miniature postsynaptic currents (mPSCs) recorded using whole-cell patch in dissociated MesV neurons were resistant to glutamate antagonists and strychnine but were reversibly abolished by 40 microM bicuculline. Superfusion of 1-10 mM GABA decreased input resistance and depolarized the membrane. Reversal potentials for evoked PSPs and GABA-induced depolarizations were similar and close to that for mPSCs which matched the Cl- equilibrium potential. Thus activation of synapses on MesV somata evokes GABAergic PSPs that generate action potentials at RMP in the adult. These data also indicate that primary afferent MesV neurons can act as interneurons in the central control of mastication.     

The effect of exhaustive exercise on the antioxidant enzyme system in skeletal muscle from calcium-deficient rats

 The aim of the current study was to elucidate the synergism of dietary calcium restriction and exhaustive exercise in the antioxidant enzyme system of rat soleus muscle, and to investigate the involvement of neutrophils in exercise-induced muscle damage. Forty-eight male Wistar rats were assigned to the following groups: control (C) or calcium-restricted [1 month (1 M) or 3 months (3 M)]. Each group was subdivided into acutely exercised or non-exercised groups. Soleus muscle from each rat was analysed to determine the levels of antioxidant enzymes [Mn-superoxide dismutase (SOD), Cu,Zn-SOD, glutathione peroxidase (GPX), and catalase (CAT)]. Dietary calcium restriction resulted in calcium deficiency and upregulated the antioxidant enzymes examined except GPX. Conversely, exhaustive exercise significantly decreased GPX and CAT, but not SODs activities in the calcium-restricted (1 M and/or 3 M) rats. Contents of immunoreactive Mn-SOD and Cu,Zn-SOD were only increased in the 3 M rats. During calcium restriction, the mRNA expression of both forms of SOD showed initial upregulation, followed by downregulation. Exhaustive exercise significantly increased the mRNA expressions only in the 3 M rats. Moreover, exhaustive exercise markedly increased myeloperoxidase activity in soleus muscles from the 1 M and 3 M rats compared with the C rats, and significantly enhanced the ability of neutrophils to generate superoxide in the 3 M rats. The results demonstrate that dietary calcium restriction upregulates certain antioxidant enzyme activities in rat soleus muscle, indicating an enhanced resistance to potential increases in intracellular reactive oxygen species. The results also suggest that exhaustive exercise may cause oxidative damage in soleus muscle of calcium-deficient rats through the activation of neutrophils. Received: 4 August 1997 / Received after revision: 29 September 1997 / Accepted: 26 November 1997