Differential Expression of Subspecies of Polyomavirus and Murine Leukemia Virus Enhancer Core Binding Protein, PEBP2, in Various Hematopoietic Cells

The core sequence of the enhancer of murine leukemia virus (MuLV) long terminal repeat is highly conserved in a large number of MuLV strains and appears to play an essential role when SL3-3 or Moloney strains induce T cell lymphoma in mice. We found by using the electrophoretic mobility shift assay that a polyomavirus enhancer core-binding protein, PEBP2, bound to this core motif of MuLV. We also noted that PEBP2 in several hematopoietic cell lines derived from B lymphocyte, macrophage and myelocyte lineages migrated significantly faster than the authentic PEBP2 detected in NIH3T3 (ibroblasts. Interestingly, PEBP2 detected in the cell lines of T lymphocyte lineage appeared to contain both types, which were indistinguishable in electrophoretic mobility from those of NIH3T3 and of B lymphocyte, macrophage and myelocyte lineages. The treatment of the nuclear extract containing PEBP2 with phosphatase generated PEBP3, which is a subcomponent of PEBP2 and retained the same DNA-binding specificity as PEBP2. The altered mobility of hematopoietic cell-derived or T lymphocyte-derived PEBP2 was found to be due to the alteration of the mobility of PEBP3. Based on the distinct mobility of PEBP2/3 of T lymphocytes from those of other hematopoietic cells, we discuss the implication of PEBP2 in MuLV-induced T cell leukemia and T cell-specific gene expression.     

Effect of alkyl groups on the rate constants of propagation and termination in the radical polymerization of dialkyl itaconates

Polymerization of dialkyl itaconates with dimethyl azoisobutyrate ( 5 ) was studied in benzene at 50°C by means of electron spin resonance (ESR). The monomers used are dimethyl ( 1 ), diethyl ( 2 ), dibutyl ( 3 ) and di-2-ethylhexyl ( 4 ) itaconates. All the polymerization systems involve ESR-observable propagating polymer radicals under the actual polymerization conditions. The polymerization rate (R_p) and degree of polymerization of the resulting polymer increase in going from shorter to longer alkyl groups. The ESR-determined rate constants of propagation (k_p) and termination (k_t) decrease as the alkyl chain becomes longer. k_p of 1 is 3,3 times higher than that of 4 , while k_t of 1 is 590 times higher than that of 4 . Thus, the steric effect due to the alkyl group suppresses much more termination than propagation, leading to the fact that R_p increases as the alkyl group becomes larger.     

Long-lived polymer radicals, 2. An ESR study on the reactions of the propagating polymer radicals of N-methylacrylamide and N-methylmethacrylamide with vinyl monomers at room temperature

Acrylamide (AAm), methacrylamide (MAm), N-methylacrylamide (NMAAm) and N-methylmethacrylamide (NMMAm) were found to yield long-lived propagating polymer radicals in the photo-sensitized polymerizations in 1,4-dioxane or benzene. The concentration of poly(NMAAm) radicals reached 1.10^?3 mol/l. Some post-effect was observed at room temperature in the photo-sensitized polymerization of AAm with di-tert-butyl peroxide in 1,4-dioxane, while no post-polymerization proceeded at room temperature in the polymerization of NMMAm in benzene. The reactions of poly(NMAAm) and poly(NMMAm) radicals with various vinyl monomers were found to produce long-lived propagating polymer radicals of the second monomers at room temperature. Polymer radicals of non-homopolymerizable monomers such as α-methylstyrene and 1,1-diphenylethylene were easily formed in such a block-copolymerization matrix. The formation of the propagating polymer radicals of the vinyl monomers was investigated by means of ESR spectroscopy.     

Vinyl polymerization initiated with the lanthanum versatate/p-chlorobenzenediazonium tetrafluoroborate system

The system of lanthanum versatate ( 1 ) and p-chlorobenzenediazonium tetrafluoroborate ( 2 ) was found to induce effectively polymerizations of electron-accepting monomers such as methyl methacrylate ( 3 ) and di-2-ethylhexyl itaconate (DEHI). The polymerization rate (R_p) was expressed by R_p = k[ 1 / 2 ]^0,44 [ 3 ]^0,65 at 50°C fixing the mole ratio of 1 and 2 at unity. The overall activation energy of the polymerization was calculated to be 37, 1 kJ · mol^?1. The spin trapping result revealed that the initiator system produces p-chloropheneyl radicals. The polymerization system of DEHI was observed to involve ESR-observable propagating polymer radicals, indicating that the polymerization initiated with the 1/2 system proceeds through radical mechanism. During the polymerization, the ESR spectrum was changed in shape, suggesting that the propagating polymer radicals interact with some species formed by the initiation reaction. Interacting polymer radicals were also observed in the polymerizations of diethyl itaconate and N-dodecylmaleimide with the 1/2 system. The polymerization systems of MMA, styrene and butyl acrylate were also found to involve ESR-observable radicals, although it is vague whether they are propagating polymer radicals or not.     

Vinyl polymerization with dimethylaniline/cupric nitrate system

A study of vinyl polymerizations initiated with the system of dimethylaniline (DMA) and cupric [Cu(II)] nitrate has been made. This initiator system was found to induce the polymerization of vinyl monomers having an electron-attracting substituent such as methyl methacrylate (MMA) and acrylonitrile, but it does not initiate the styrene and vinyl acetate polymerizations. The rate of polymerization (R_p) of MMA with this system was expressed by the following Eqs., depending upon the Cu(II) concentration used: The apparent activation energy for this polymerization was found to be 16.5 and 14.4 kcal/mole for the above two Cu(II) concn. ranges, respectively. The polymer of MMA obtained by this system was found to contain an endgroup similar to dimethylaniline, probably a methylanilinomethyl group, from the determination of its UV spectrum.     

Metal-containing initiator systems, 34. Polymerization of vinyl monomers initiated by the binary system cobaltocene/bis(ethyl acetoacetato)copper (II)

The effect of some metallocenes such as ferrocene (Fe(C₅H₅)₂), nickelocene (Ni(C₅H₅)₂), and cobaltocene (Co(C₅H₅)₂), on the vinyl polymerization initiated with bis(ethyl acetoacetato)-copper(II) (Cu(eacac)₂) was investigated. Co(C₅H₅)₂ was found to exert a markedly accelerating effect on the polymerization of methyl methacrylate (MMA) with Cu(eacac)₂. The polymerization of MMA with the system Co(C₅H₅)₂/Cu(eacac)₂ at 50°C was found to be fairly affected by the solvent used. The results of copolymerization of MMA with styrene (St) and the effect of hydroquinone (HQ) on the polymerization of MMA with Co(C₅H₅)₂/Cu(eacac)₂ showed that the polymerization proceeds via a radical mechanism. The polymerization of MMA with Co(C₅H₅)₂/Cu(eacac)₂ was studied kinetically in acetone. The overall activation energy of the polymerization was calculated to be 86,3 kJ/mol (20,6 kcal/mol). This value was somewhat higher than that (17,6 kcal/mol) obtained for the polymerization of MMA with Cu(eacac)₂ alone. The polymerization rate (R_p) is represented by the following equation: R_p = k[Co(C₅H₅)₂]^0,5 [Cu(eacac)₂]^0,2 [MMA]^1,3. The high order in monomer concentration suggests a participation of the monomer in the initiation process of this polymerization. This is supported by the examination of the ESR spectrum of the system Co(C₅H₅)₂/Cu(eacac)₂/MMA/acetone, where reduction of Cu(II) to Cu(I) occurs. To elucidate the initiation mechanism, the spin trapping technique was applied to the system Co(C₅H₅)₂/Cu(eacac)₂/methyl acrylate. From these results, an initiation mechanism for the binary initiator system Co(C₅H₅)₂/Cu(eacac)₂ is proposed and discussed.     

Endocannabinoid system modulates relapse to methamphetamine seeking: possible mediation by the arachidonic acid cascade.

We clarified the modulating action of the endocannabinoid system, and its possible mediation by the arachidonic acid cascade, on the reinstatement of methamphetamine (METH)-seeking behavior, using the intravenous self-administration paradigm in rats. Following 12 days of self-administration of METH, the replacement of METH with saline resulted in a gradual decrease in lever press responses (extinction). Under extinction conditions, METH-priming or re-exposure to cues previously paired with METH infusion markedly increased the responses (reinstatement of drug-seeking). The cannabinoid CB1 receptor antagonist, SR141716A, blocked this behavior. Although the cannabinoid agonist, Delta8-tetrahydrocannabinol (THC), had no effects by itself, coadministration of the agonist and METH at small doses reinstated the drug-seeking behavior. THC attenuated the effects of the reinstatement-inducing dose of METH, but enhanced the effect of cues. Either given repeatedly during the extinction or singly, 24 h before the first METH-priming or cues challenge, THC suppressed the reinstatement. In another set of experiments, we found that diclofenac, a cyclooxygenase inhibitor, also attenuated the reinstatement induced by exposure to cues or drug-priming. These results suggest that the endocannabinoid system, through possible mediation by the arachidonic acid cascade, serves as a modulator of the reinstating effects of METH-priming and cues. Extending the current view on the treatment of drug dependence, these results indicate that endocannabinoid-activating substances as well as cyclooxygenase inhibitors may be promising as antirelapse agents.     

Influences of season and of temperature, photoperiod, and subcutaneous melatonin infusion on the glomerular filtration rate of ewes

Abstract: Influences of season and of temperature, photoperiod, and subcutaneous melatonin infusion on glomerular filtration rate (GFR) were measured in ewes. There was a seasonal difference of GFR between summer (June-August) and winter (December-February) in Tokyo (35°, 35°N); GFR was significantly ( P < 0.05) higher in summer (4.2 ± 0.3 ml/ min/kg) than in winter (3.0 ± 0.2 ml/min/kg). GFR was measured after exposure to three types of photoperiod, 24L: 0D, 12L: 12D, and 0L: 24D, for 7 to 8 days. The value for GFR obtained at 20°C was significantly lower ( P < 0.05) with 0L: 24D than with the other two photoperiodic conditions. GFR obtained during subcutaneous melatonin infusion (20μg/hr for 16 hr/ day for 7 days) with 24L: 0D conditions was significantly ( P < 0.05) lower (2.5 ± 0.1 ml/min/kg) than without infusion (3.8 ± 0.3 ml/ min/kg) and was about the same as that obtained in animals under 0L: 24D conditions. At 30°C, GFR exhibited no difference between the 3 photoperiodic conditions and was always lower than that found at 20°C. Possible influences of melatonin on GFR are discussed.     

Mechanisms of action of mazindol in preventing onset and development of obesity induced by gold thioglucose injection

Biochemical and morphological studies were made on the role of mazindol in treatment of obesity in mice induced by gold thioglucose (GTG) injection. Mazindol was added to the diet at a level of 10 mg/kg body weight and then all animals were fed on a constantly restricted diet of 60 percent of the level of ad lib, food intake for 10 weeks. The following results were obtained: (1) The body weight and Lee's index were significantly increased by GTG injection and these increases in the GTG-obese group were reduced by oral mazindol. (2) The levels of triglyceride and cholesterol in the liver were much higher in the GTG-obese group than in the lean group, and were significantly less in the mazindol-treated group than in the GTG-obese group. (3) The levels of serum triglyceride and immunoreactive insulin were significantly higher in the GTG group than in the lean group and the increase in the GTG-treated animals was reduced by oral mazindol. (4) The size of fat cells and basal lipolytic activity in parametrial adipose tissue were greater in the GTG-obese group than in the lean group and were significantly reduced by mazindol treatment. (5) Disaccharidase activities in the small intestinal mucosa and the absorptive surface area of the mucosa were significantly greater in the GTG-obese group than in the lean group and were increased significantly less in the mazindol-treated group.     

Soluble transferrin receptor and its ratio to erythroblasts in bone marrow may be a new diagnostic tool to distinguish between aplastic and refractory anemia

Myelodysplastic syndromes (MDS), especially refractory anemia (RA) are very heterogeneous diseases regarding their morphological, biological and clinical features. One important clinical problem is the difficulty of diagnosis. Soluble transferrin receptors (sTfRs) reflect the erythropoietic activity in the bone marrow (BM). To establish whether determination of serum sTfR could be useful for the differential diagnosis between RA and aplastic anemia (AA), we measured the serum sTfR concentrations, BM cellularity and BM erythroblast percentages in 14 untreated AA and 7 untreated RA patients. The serum sTfR levels of the RA patients (820.1 +/- 402.8 ng/ml) were significantly higher than those of the AA patients (491.1 +/- 195.2 ng/ml; p = 0.0207). However, the serum sTfR values of RA and AA patients also overlapped. A new index, the 'sTfR-E index' [the ratio of serum sTfR level (ng/ml) to BM cellularity (%) x BM erythroblasts (%)] is proposed, which is expected to reflect the number of transferrin receptors (TfR) on the cell membrane per BM erythroblast. The sTfR-E index values of the 7 RA patients (0.395 +/- 0.234) were significantly lower than those of the 14 AA patients (2.669 +/- 1.633; p = 0.0003). The sTfR-E index values of AA and RA patients overlapped only marginally. In conclusion, the sTfR-E index may be a useful new diagnostic tool to distinguish between AA and RA patients.