Formation of N1-acetylspermidine in rat liver after treatment with carbon tetrachloride

A single intraperitoneal injection of carbon tetrachloride produced a significant increase in the concentration of N¹-acetylspermidine in rat liver. The concentration of N¹-acetylspermidine was maximal at the same time after injection at which other workers reported maximal conversion of spermidine to putrescine and maximal acetylase activity in liv liver extracts. N¹-acetylspermidine was not detectable in livers of untreated animals and at 45 hours after injection with monoacetylation of polyamines precedes their degradation by polyamine oxidases. Spleen, lungs and erythrocytes of untreated animals contained detectable amounts of the monoacetyl polyamines. Treatment with carbon tetrachloride did not produce changes in the concentrations of the monoacetyl polyamines in these tissues.     

A NUCLEAR MEMBRANE CHANGE AFTER PARTIAL HEPATECTOMY

Partial hepatectomy (67 per cent extirpation) of the rat leads to a change in the membrane of liver nuclei (purified with citric acid) detectable as an increase in electrophoretic mobility. No change is detectable 2 hours after the operation, but between 2 and 6 hours about a 1.4-fold increase in mobility occurs after which the mobility becomes constant at the elevated level. Removal of only 10 per cent of the liver causes no detectable change in 6 hours. Bilateral adrenalectomy immediately before partial hepatectomy does not affect the development of the nuclear change. Actinomycin D and p-fluorophenylalanine, but not noradrenalin, ionizing radiation, or EDTA, suppress the increase in electrophoretic mobility. The level of actinomycin D required to block the nuclear membrane change is 6 times greater than that necessary to prevent the rate increase in hepatic RNA metabolism that follows removal of part of the liver. This discrepancy and the difference in the response to noradrenalin indicate that, at least initially, the nuclear membrane change and the change in the rate of RNA synthesis are independent processes. The inability of EDTA to block the nuclear membrane change shows that the Zn⁺⁺ requirement for DNA replication is not related to the events that lead to the alteration in the electrokinetic properties of liver nuclei.     

Stimulation of hepatic phosphatidate phosphohydrolase activity by a single dose of ethanol;.

An acute ethanol load (5 g per kg body wt) given by gastric intubation to fasted rats caused a significant increase in phosphatidate phosphohydrolase activity in the soluble fraction of the liver. The activity was two-fold at 8 hours and three-fold at 16 hours after the ethanol administration and decreased to the control level a few hours after the disappearance of ethanol from the blood. Results from in vivo experiments with intraportally injected [³H]glycerol showed an ethanol-induced cross-over point between glycerol incorporation into phosphatidic acid and neutral glycerolipids. This cross-over could be observed only when the phosphatidate phosphohydrolase activity was increased.     

Mitochondrial RNA and protein synthesis in enucleated African green monkey cells

The behavior of extramitochondrial protein synthesis and of mitochondrial RNA and protein synthesis was examined in the cytoplasts of African green monkey kidney cells (TC-7 subline) at different times following enucleation by cytochalasin B. The rate of incorporation of [³H]isoleucine into protein of the soluble cytoplasmic fraction decreased in an approximately exponential fashion, with a half-life of about five hours, during the first 26 hours after enucleation. Discrete mitochondrial 16 S, 12 S and 4 S RNA components were identified among the products of cytoplast RNA synthesis. The rates of [³H]uridine incorporation into the 16 and 12 S RNA components as well as into total RNA declined progressively after enucleation to a barely detectable level by the 20th hour. By contrast, the rate of chloramphenicol-sensitive [³H]isoleucine incorporation into protein (due to mitochondrial protein synthesis) did not undergo a substantial decline for at least 20 hours in TC-7 cytoplasts; instead, a reproducible transient stimulation occurred in the first hours following enucleation. The products of mitochondrial protein synthesis pulse-labeled in nucleated cells and in cytoplasts 24 hours after enucleation exhibited similar electrophoretic profiles.     

Plasma amino acid levels after carbon tetrachloride induced acute liver damage. A dose-response and time-response study in rats

Summary The aims of the present study were to assess the changes of individual plasma amino acid levels in relation (1) to the severity of liver damage and (2) to the process of liver recovery. Acute liver injury was induced by an intragastric administration of CCl₄ diluted in olive oil in doses of 2, 4 and /or 6 g of CCl₄ per kg b.w. The control rats received olive oil only. Animals were sacrificed at 16, 24, 48 and 96 hours after treatment. The severity of liver injury was assessed by histological examination, by changes in ALT and AST in the blood plasma and by changes in liver weight. Statistical analysis was carried by ANOVA, p < 0.05 was considered significant. The Spearman rank correlation coefficient was used as a measure of the degree of linear relationship between variable and dose. In the period of the development of acute liver damage, i.e. at 16 and 24 hours after treatment, an increase in blood plasma amino acid levels and positive correlations with the dose of CCl₄ were observed for most individual amino acids. The only exception was arginine which decreased in a dose dependent manner. At a phase of liver recovery, i.e. at 48 and 96 hours after CCl₄ treatment, the concentrations of some individual amino acids decreased below the control values. The negative correlation with the dose of CCl₄ occurred for taurine and isoleucine (at 48 hours) and taurine, threonine, valine, methionine, isoleucine and leucine (at 96 hours).     

Kinetics of nickel binding in hepatic and renal cytosol of63NiCl2-treated rats

Elution profiles of nickel-binding protein were investigated in hepatic and renal cytosol of rats at various time intervals (6, 16, 24, and 48 h) after intraperitoneal administration of⁶³Ni (1 mg Ni/kg. B. Wt. = 400 µCi as⁶³NiCl₂). The nickel-binding proteins were characterized in terms of absorbance at 254 nm, sulfhydryl content, and⁶³Ni counts. The results demonstrated that in liver it was bound to both high as well as low mol wt sulfhydryl proteins and glutathione-like moiety with a maximum incorporation at 16 h, after which it declined and by 48 h, very little⁶³Ni was associated with the bioligands. In kidney the incorporation of⁶³Ni was approximately 400-fold higher than liver and most of⁶³Ni was associated with the low mol. wt. sulfhydryl moiety. Kidney also exhibited maximum incorporation of⁶³Ni at 16 h that was metabolized by 48 h.     

Heat Shock Proteins and Their mRNAs in Dry and Early Imbibing Embryos of Wheat

Two-dimensional gels of in vitro translation products of mRNAs isolated from quiescent wheat (Triticum aestivum) embryos demonstrate the presence of mRNAs encoding heat shock proteins (hsps). There were no detectable differences in the mRNAs found in mature embryos from field grown, from 25°C growth chamber cultivated, or from plants given 38°C heat stresses at different stages of seed development. The mRNAs encoding several developmentally dependent (dd) hsps were among those found in the dry embryos. Stained two-dimensional gels of proteins extracted from 25°C growth chamber cultivated wheat embryos demonstrated the presence of hsps, including dd hsps. A study of the relationship of preexisting hsp mRNAs and the heat shock response during early imbibition was undertaken. Heat shocks (42°C, 90 minutes) were administered following 1.5, 16, and 24 hours of 25°C imbibition. While the mRNAs encoding the low molecular weight hsps decayed rapidly upon imbibition, the mRNAs for dd hsps persisted longer and were still detectable following 16 hours of imbibition. After 1.5 hours of imbibition, the mRNAs for the dd hsps did not accumulate in response to heat shock, even though the synthesis of the proteins was enhanced. Thus, an applied heat shock appeared to lead to the preferential translation of preexisting dd hsp mRNAs. The mRNAs for the other hsps, except hsp 70, were newly transcribed at all of the imbibition times examined. The behavior of the hsp 70 group of proteins during early imbibition was examined by RNA gel blot analysis. The mRNAs for the hsp 70 group were detectable at moderate levels in the quiescent embryo. The relative level of hsp 70 mRNA increased after the onset of imbibition at 25°C and remained high through 25.5 hours of prior imbibition. The maximal levels of these mRNAs at 25°C was reached at 17.5 hours of imbibition. Heat shock caused modest additional accumulation of hsp70 mRNA at later imbibition times.     

Safety and Immunogenicity of DNA and MVA HIV-1 Subtype C Vaccine Prime-Boost Regimens: A Phase I Randomised Trial in HIV-Uninfected Indian Volunteers

Study Design

A randomized, double-blind, placebo controlled phase I trial.

Methods

The trial was conducted in 32 HIV-uninfected healthy volunteers to assess the safety and immunogenicity of prime-boost vaccination regimens with either 2 doses of ADVAX, a DNA vaccine containing Chinese HIV-1 subtype C env gp160, gag, pol and nef/tat genes, as a prime and 2 doses of TBC-M4, a recombinant MVA encoding Indian HIV-1 subtype C env gp160, gag, RT, rev, tat, and nef genes, as a boost in Group A or 3 doses of TBC-M4 alone in Group B participants. Out of 16 participants in each group, 12 received vaccine candidates and 4 received placebos.

Results

Both vaccine regimens were found to be generally safe and well tolerated. The breadth of anti-HIV binding antibodies and the titres of anti-HIV neutralizing antibodies were significantly higher (p<0.05) in Group B volunteers at 14 days post last vaccination. Neutralizing antibodies were detected mainly against Tier-1 subtype B and C viruses. HIV-specific IFN-γ ELISPOT responses were directed mostly to Env and Gag proteins. Although the IFN-γ ELISPOT responses were infrequent after ADVAX vaccinations, the response rate was significantly higher in group A after 1^st and 2^nd MVA doses as compared to the responses in group B volunteers. However, the priming effect was short lasting leading to no difference in the frequency, breadth and magnitude of IFN-γELISPOT responses between the groups at 3, 6 and 9 months post-last vaccination.

Conclusions

Although DNA priming resulted in enhancement of immune responses after 1^st MVA boosting, the overall DNA prime MVA boost was not found to be immunologically superior to homologous MVA boosting.

Trial Registration

Clinical Trial Registry CTRI/2009/091/000051     

Interconversion of 16-epioestriol and oestriol by avian liver tissue in vitro

1. [16-¹⁴C]16-Epioestriol and [6,7-³H₂]oestriol were incubated both simultaneously and separately at 40° with hen liver homogenates obtained from birds in the laying stage. 2. Purification and identification of products was made by ether extraction, Girard separation, Celite partition and paper chromatography and crystallization to constant specific activity both with and without derivative formation. Percentage conversions of the radioactive 16-epioestriol and oestriol were calculated from these specific activities. 3. Oestriol yielded 16-epioestriol as early as 5min. after exposure of steroid to the tissue. No production of oestriol from 16-epioestriol was detectable in this time. 4. Considerably more 16-epioestriol was formed from oestriol than oestriol by the reverse reaction after 90min. of incubation. 5. 16-Oxo-oestradiol-17β appeared in all cases to be the major identified intermediate in the interconversion of 16-epioestriol and oestriol.     

Comparative analysis of proteins labelled with [35S]methionine in the liver in vivo and in freshly isolated and short-term-cultured hepatocytes in vitro

[³⁵S]Methionine-labelled liver proteins, analysed by one- or two-dimensional gel electrophoresis showed a strikingly similar pattern whether synthesized in vivo or by freshly isolated hepatocytes. In contrast, major qualitative and quantitative differences were observed with the patterns of labelled proteins found in cultured hepatocytes. The changes detectable very early (within 1 h) in culture affected preferentially the synthesis of cytoskeleton proteins (cytokeratins, actin, myosin), which was dramatically increased. Physical factors like cell attachment appear to be responsible for these changes which, however, occurred more rapidly in the presence of serum. Freshly isolated hepatocytes and short-term-cultured cells responded similarly to insulin and glucagon, which respectively increased and decreased the labelling of the whole set of cellular and exported proteins. Glucocorticoids caused either an increase or a decrease in the labelling of several proteins, but the effects were detectable only under chronic exposure of cultured hepatocytes. Based on these results, freshly isolated hepatocytes appear more representative of the liver in vivo than cultured hepatocytes, and therefore seem more suitable for short-term studies. However, cultured hepatocytes can be used for long-term studies since they maintain many specific liver functions and remain hormonally sensitive.     

Expression of nuclear matrix proteins in rat liver tissue

We have studied the synthesis of nuclear matrix proteins as it occurs in the rat liver. To investigate their kinetics in tissue, nuclear matrix proteins were prepared from liver of rats injected with radioactive methionine. Synthesis of lamins was not observed in quiescent hepatocytes although they were the principal proteins of this subcellular fraction, suggesting that lamins are very stable in the liver. When hepatocytes were stimulated to divide by partial hepatectomy, only synthesis of lamin B was initiated. Many proteins not visible on Coomassie blue-stained gels were detectable by autoradiography. In the nuclear matrix extracts of quiescent hepatocytes, one of the most prominently labeled ones was a protein of 70 kDa. After hepatectomy, an additional protein of 62 kDa was detectable. These proteins were visible 1 h after the injection of radioactivity, but were no longer observed in nuclear matrices prepared 24 h after injection. These experiments indicate that in addition to lamins, two nuclear matrix proteins are present in the rat liver that were not detected previously, perhaps because of their rapid turnover.     

Isoprenylated Proteins in Myelin

Abstract: Incubation of rat brainstem slices with [³H]- mevalonate ([³H]MVA) in the presence of lovastatin resulted in the incorporation of label into three groups of myelin-associated proteins with molecular masses of 47, 21–27, and 8 kDa, as revealed on sodium dodecyl sulfate- polyacrylamide rod gel electrophoresis. Although the gel patterns of [³H]MVA-derived prenylated proteins were similar, the relative level of ³H incorporated into each protein species differed between myelin and the brainstem homogenate. Immunoprecipitation studies identified the 47-kDa prenylated protein as a 2′-3′-cyclic nucleotide phospho- diesterase, whereas the 8-kDa protein proved to be the γ subunit of membrane-associated guanine nucleotide regulatory protein. The ³H-labeled 21–27-kDa group in myelin corresponds to the molecular mass of the extensive Ras- like family of monomeric GTP-binding proteins known to be prenylated in other tissues. Increase in lovastatin concentration resulted in reduced levels of [³H]MVA-labeled species in myelin and concomitantly increased levels in the cytosol. A cold MVA chase restored to normality the appearance of [³H]MVA-labeled proteins in myelin. Furthermore, a high lovastatin concentration in the brainstem slice incubation mixture altered the appearance of newly synthesized nonprenylated myelin proteins, including proteolipid protein and the 17-kDa subspecies of myelin basic protein. Because other myelin proteins were unaffected by the high lovastatin concentration, restricting the availability of MVA in myelin-forming cells may selectively alter processes required for myelinogenesis. Although the molecular basis for the” different MVA requirements in myelin- forming cells remains undefined, it may involve an alteration in the biological activity of certain proteins that require prenylation to be functionally active, and that are responsible for promoting insertion of specific proteins into the myelin membrane.     

Studies of the in vivo metabolism of mevalonic acid in the neonatal chick

After 4 hr of the intraperitoneal injection of different doses of (R)-[5-14C]mevalonic acid (MVA), its incorporation into nonsaponifiable and saponifiable lipids was maximal in neonatal chick kidneys and liver, and minimal in brain, spinal cord and skin. Using 14CO2 production from [5-14C]MVA as an index of the shunt pathway not leading to sterols, we have demonstrated for the first time that about 11% of MVA was in vivo metabolized by this pathway in nonmammalian species. Kidneys presented the maximal ability to incorporate MVA into nonsaponifiable and saponifiable lipids at any time considered (15-750 min). The percentage of radioactivity recovered as saponifiable lipids in liver and kidney decreased after 12 hr the injection of MVA. Although the absolute amounts of 14C incorporated in both derivatives were much less in brain, spinal cord and skin than in liver and kidneys, the relative percentages found in the saponifiable fraction were clearly higher in the former tissues, especially in the spinal cord.     

Antibody profiling by proteome microarray reveals the immunogenicity of the attenuated smallpox vaccine modified vaccinia virus ankara is comparable to that of Dryvax

Modified vaccinia virus Ankara (MVA) is a highly attenuated vaccinia virus that is under consideration as an alternative to the conventional smallpox vaccine Dryvax. MVA was attenuated by extensive passage of vaccinia virus Ankara in chicken embryo fibroblasts. Several immunomodulatory genes and genes that influence host range are deleted or mutated, and replication is aborted in the late stage of infection in most nonavian cells. The effect of these mutations on immunogenicity is not well understood. Since the structural genes appear to be intact in MVA, it is hypothesized that critical targets for antibody neutralization have been retained. To test this, we probed microarrays of the Western Reserve (WR) proteome with sera from humans and macaques after MVA and Dryvax vaccination. As most protein sequences of MVA are 97 to 99% identical to those of other vaccinia virus strains, extensive binding cross-reactivity is expected, except for those deleted or truncated. Despite different hosts and immunization regimens, the MVA and Dryvax antibody profiles were broadly similar, with antibodies against membrane and core proteins being the best conserved. The responses to nonstructural proteins were less well conserved, although these are not expected to influence virus neutralization. The broadest antibody response was obtained for hyperimmune rabbits with WR, which is pathogenic in rabbits. These data indicate that, despite the mutations and deletions in MVA, its overall immunogenicity is broadly comparable to that of Dryvax, particularly at the level of antibodies to membrane proteins. The work supports other information suggesting that MVA may be a useful alternative to Dryvax.     

共表达猪呼吸与繁殖障碍综合征病毒NJ-a株ORF4、ORF5与ORF6基因重组改良型痘苗病毒安卡拉株的构建

为探讨共表达猪繁殖与呼吸综合征病毒(Porcinerep roductive and respiratory syndrome Virus,PRRSV)保护性抗原基因的重组改良型痘苗病毒安卡拉株(Modified Vaccinia Virus Ankala,MVA)的免疫效力,将PRRSVNJ-a株ORF4、ORF5和ORF6基因插入转移载体pⅡLR中,获得了三基因共表达的转移载体pⅡLR-ORF5/ORF6/ORF4,通过同源重组的方法获得重组病毒rMVA-GP5/M/GP4。以lacZ为报告基因进行噬斑筛选和重组病毒纯化后,PCR方法证明ORF4、ORF5和ORF6成功的插入MVA基因组中;经Western blot检测与间接免疫荧光试验证实,重组病毒感染细胞能正确表达PRRSVGP4、GP5与M蛋白。用rMVA-GP5/M/GP4免疫6周龄Babl/C小鼠,首免后3周可检测到特异性PRRSV中和抗体,8周后中和抗体效价可达25,并能继续维持4周;淋巴细胞增殖试验结果表明,重组病毒免疫小鼠产生强烈的特异性细胞增殖反应。上述研究结果表明rMVA-GP5/M/GP4具有良好的免疫原性,可作为预防PRRS的候选疫苗进一步研究。     

Embryonic synthesis of myoglobin in vivo estimated by radioimmunoassay

Chick embryos in ovo incorporated radioactivity from lysine-U-¹⁴C into myoglobin, as measured by an immunoprecipitation technique. The most consistent results were obtained by injection of the precursor into the yolk sac fluid.Incorporation, or apparent myoblobin synthesis, occurred in cardiac and skeletal muscle but not in liver, although incorporation of amino acid into total soluble proteins was equivalent in all tissues studied. Synthesis was highest in cardiac muscle and appeared there first in younger embryos. Myoglobin synthesis was detectable in the heart of embryos as early as 6 days of age and rose with age thereafter. Myoglobin synthesis appeared later and at lower levels in skeletal muscle.In vitro at neutral pH, tissue extracts of liver and muscle possessed only slight properties of myoglobin degradation.Using nonradioactive precipitin techniques, sensitive to 5–10 μg/ml, myoglobin was detected in embryonic heart muscle by week 2 of life and rose in content thereafter. Two of 8 embryos had trace amounts in thigh muscle near the time of hatching, and no embryos possessed measurable amounts of myoglobin in liver tissue or in pectoral skeletal muscle. Adult birds possessed equivalent amounts of myoglobin in heart and thigh muscle while pectoral muscle and liver tissue had no detectable myoglobin content.     

Phosphorylation of nuclear matrix proteins in isolated regenerating rat liver nuclei

The phosphorylation of nuclear matrix proteins from normal and regenerating rat liver nuclei was examined using an $\text{in vitro}$ system of isolated nuclei and γ-³²P-ATP. Phosphorylation of the nuclear matrix proteins was 2–3 fold higher than that of the total nuclear proteins in normal nuclei. The level of phosphorylation of the matrix proteins was enhanced an additional three fold at a period in liver regeneration (12 hours) just preceding the onset of DNA synthesis.     

Improving the MVA vaccine potential by deleting the viral gene coding for the IL-18 binding protein

Background

Modified Vaccinia Ankara (MVA) is an attenuated strain of Vaccinia virus (VACV) currently employed in many clinical trials against HIV/AIDS and other diseases. MVA still retains genes involved in host immune response evasion, enabling its optimization by removing some of them. The aim of this study was to evaluate cellular immune responses (CIR) induced by an IL-18 binding protein gene (C12L) deleted vector (MVAΔC12L).

Methodology/Principal Findings

BALB/c and C57BL/6 mice were immunized with different doses of MVAΔC12L or MVA wild type (MVAwt), then CIR to VACV epitopes in immunogenic proteins were evaluated in spleen and draining lymph nodes at acute and memory phases (7 and 40 days post-immunization respectively). Compared with parental MVAwt, MVAΔC12L immunization induced a significant increase of two to three-fold in CD8⁺ and CD4⁺ T-cell responses to different VACV epitopes, with increased percentage of anti-VACV cytotoxic CD8⁺ T-cells (CD107a/b⁺) during the acute phase of the response. Importantly, the immunogenicity enhancement was also observed after MVAΔC12L inoculation with different viral doses and by distinct routes (systemic and mucosal). Potentiation of MVA''s CIR was also observed during the memory phase, in correlation with a higher protection against an intranasal challenge with VACV WR. Of note, we could also show a significant increase in the CIR against HIV antigens such as Env, Gag, Pol and Nef from different subtypes expressed from two recombinants of MVAΔC12L during heterologous DNA prime/MVA boost vaccination regimens.

Conclusions/Significance

This study demonstrates the relevance of IL-18 bp contribution in the immune response evasion during MVA infection. Our findings clearly show that the deletion of the viral IL-18 bp gene is an effective approach to increase MVA vaccine efficacy, as immunogenicity improvements were observed against vector antigens and more importantly to HIV antigens.     

Effects of pravastatin sodium on mevalonate metabolism in common marmosets

In experimental animals and humans, the concentration of serum mevalonate (MVA), a direct product of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, is considered to reflect the activity of whole-body sterol synthesis. The relationship between the concentration of serum MVA and the activity of sterol synthesis in tissues, however, has not been fully clarified. In the present study, we examined MVA metabolism by using pravastatin, a liver-selective inhibitor of HMG-CoA reductase, and common marmosets, a good model animal for studying lipid metabolism. In the time course study, the maximal reduction in the concentration of serum MVA was observed 2 h after a single oral administration of 30 mg/kg pravastatin to common marmosets. We, therefore, examined the relationship between the concentrations of serum and hepatic MVA, and sterol synthesis in some tissues at this time point. Sterol synthesis was determined ex vivo in tissue slices by measuring the incorporation of [14C]acetate into digitonin-precipitable [14C]sterols. Pravastatin at 0.03-30 mg/kg reduced dose-dependently the activity of hepatic sterol synthesis, whereas no significant reduction of sterol synthesis was observed in other tissues such as intestine, kidney, testis and spleen, even with the highest dose (30 mg/kg). The liver-specific inhibition of sterol synthesis caused parallel reductions in the concentrations of both serum and liver MVA. In addition, there were good correlations between the concentration of either serum or hepatic MVA and the activity of hepatic sterol synthesis. These data indicate that the major origin of serum MVA is the liver, and that the concentration of serum MVA reflects the concentration of hepatic MVA and the activity of hepatic sterol synthesis 2 h after a single oral administration of pravastatin in common marmosets.