OBJECTIVE

To evaluate the effects of early exercise training in patients recovering from acute respiratory failure needing mechanical ventilation (MV).

METHODS

Prospective, randomized, and controlled study.

METHODS

Three respiratory intermediate ICUs (RIICUs).

METHODS

Of 228 patients admitted to an RIICU, 66 patients weaned from MV from>> 48 to < 96 h were considered eligible and enrolled in the study.

METHODS

Sixty-six patients were randomized to either supported arm exercise training plus general physiotherapy (gPT) [group 1, 32 patients] or to gPT alone (group 2, 34 patients).

RESULTS

Twenty-five patients in each group completed the protocol. Group 1 showed a greater improvement in exercise capacity, as assessed by an arm incremental test (IT) [p = 0.003] and an endurance test (ET) [p = 0.021], compared to group 2. Posttraining maximal inspiratory pressure (MIP) significantly improved in both groups (p < 0.001 and p = 0.003 in groups 1 and 2 respectively; not significant). IT isoworkload dyspnea improved significantly in both groups (p = 0.005 and p = 0.009 in groups 1 and 2, respectively; not significant between groups), whereas IT isoworkload peripheral muscle fatigue (p < 0.001), ET isotime dyspnea (p < 0.01), and ET isotime muscular fatigue (p < 0.005) improved significantly in group 1 but not in group 2. IT improvers (chi2 = 0.004) and ET improvers (chi2 = 0.047) were more frequently observed in group 1 than in group 2. Baseline MIP could discriminate for IT (p = 0.013; odds ratio [OR], 1.116) and ET improvers (p = 0.022; OR, 1.067).

CONCLUSIONS

Early upper-limb exercise training is feasible in RIICU patients recently weaned from MV and can enhance the effects of gPT. Baseline inspiratory muscle function is related to exercise capacity improvement.

We have developed an assay for transient gene expression using a dominant-selectable marker previously employed to transform Drosophila cultured cells. Drosophila hydei cells transfected with a functional Escherichia coli xanthine guanine phosphoribosyl transferase gene (gpt), under the control of the long terminal repeats (LTRs) of the copia transposable element, rapidly incorporate guanine into acid-precipitable counts. Autoradiographic analysis in situ shows that approximately 20% of cells take up, and express, the gpt gene. This transient gpt expression depends on the Drosophila promoter sequences since vectors with the gpt gene in reverse orientation to the copia LTRs fail to incorporate guanine. Deletion analysis confirms that the LTRs are essential for gpt gene expression. Similarly, cells transfected with gpt controlled by the Drosophila 70 000 mol. wt. heat-shock (hsp 70) promoter show regulated guanine incorporation when heat shocked. The efficiency of the copia LTRs varies considerably between the cell lines we tested, whereas that of the hsp 70 promoter does not. The heterologous promoters of the Rous sarcoma virus (RSV) and simian virus 40 (SV40) function poorly in these cells.

BACKGROUND

Titanium dioxide (TiO2) nanoparticles and fullerene (C60) are two attractive manufactured nanoparticles with great promise in industrial and medical applications. However, little is known about the genotoxic response of TiO2 nanoparticles and C60 in mammalian cells. In the present study, we determined the mutation fractions induced by either TiO2 nanoparticles or C60 in gpt delta transgenic mouse primary embryo fibroblasts (MEF) and identified peroxynitrite anions (ONOO-) as an essential mediator involved in such process.

RESULTS

Both TiO2 nanoparticles and C60 dramatically increased the mutation yield, which could be abrogated by concurrent treatment with the endocytosis inhibitor, Nystatin. Under confocal scanning microscopy together with the radical probe dihydrorhodamine 123 (DHR 123), we found that there was a dose-dependent formation of ONOO- in live MEF cells exposed to either TiO2 nanoparticles or C60, and the protective effects of antioxidants were demonstrated by the nitric oxide synthase (NOS) inhibitor, NG-methyl-L-arginine (L-NMMA). Furthermore, suppression of cyclooxygenase-2 (COX-2) activity by using the chemical inhibitor NS-398 significantly reduced mutation frequency of both TiO2 nanoparticles and C60.

CONCLUSIONS

Our results provided novel information that both TiO2 nanoparticles and C60 were taken up by cells and induced kilo-base pair deletion mutations in a transgenic mouse mutation system. The induction of ONOO- may be a critical signaling event for nanoparticle genotoxicity.

In order to cast light on carcinogen-specific molecular mechanisms underlying experimental hepatocarcinogenesis in rats, in vivo mutagenicity and mutation spectra of known genotoxic rat hepatocarcinogens N-nitrosopyrrolidine (NPYR), and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), as well as the nongenotoxic hepatocarcinogen di(2-ethylhexyl)phthalate (DEHP) and the noncarcinogen acetaminophen (AAP), were investigated in guanine phosphoribosyltransferase (gpt) delta transgenic rats, a recently developed animal model for genotoxicity analysis. After 13-wk treatment, glutathione S-transferase placental form (GST-P)-positive liver cell foci were significantly increased in NPYR-treated and IQ-treated rats. In the DEHP-treated rats, marked hepatomegaly with centrilobular hypertrophy of hepatocytes occurred, although GST-P staining was consistently negative. Positive mutagenicity was detected in IQ- and NPYR-treated rats. Mutant frequencies (MFs) in the liver DNA were 188.0 x 10(-6) and 56.5 x 10(-6), approximately 35-fold and 10-fold higher, respectively, than that of nontreatment control rats (5.5 x 10(-6)). There were no increases in MFs in the DEHP- or AAP-treated rats as compared to the nontreatment control value. IQ induced mainly base substitutions leading to G:C to T:A transversions (56.9%) and deletions of G:C base pairs. In contrast, NPYR primarily caused specific A:T to G:C transitions (49.3%), which are very rare in the other groups. These data provided support for the conclusion that IQ and NPYR hepatocarcinogenesis depends on genotoxic processes and specific DNA adduct formation while DEHP exerts its influence via a nongenotoxic promotional pathway. Our data also indicate that analysis of specific in vivo mutational responses with transgenic animal models can provide crucial information for understanding the molecular mechanisms underlying chemical carcinogenesis.

Hepatoprotective effect of andrographolide (the major active diterpenoid lactone of the plant Andrographis paniculata) was studied on acute hepatitis induced in rats by single dose of galactosamine (800 mg/kg, ip)/paracetamol (3g/kg, po). Hepatoprotective activity was monitored by estimating the serum transaminases (GOT and GPT), alkaline phosphatase and bilirubin in serum, hepatic triglycerides, and by histopathological changes in the livers of experimental rats. Pre-treatment and/or post-treatment of rats at different time intervals with different doses of andrographolide in the two experimental models of hepatotoxicity showed that treatment of rats with 400 mg/kg, ip or 800 mg/kg, po, 48, 24 and 2 h before galactosamine administration or with 200 mg/kg, ip, 1, 4 and 7 h after paracetamol challenge leads to complete normalisation of toxin-induced increase in the levels of all the five biochemical parameters, and significantly ameliorates toxin-induced histopathological changes in the livers of experimental rats. The results confirmed the in vivo hepatoprotective effect of andrographolide against galactosamine or paracetamol-induced hepatotoxicity in rats. Since the protective effect of andrographolide was observed in two types of intoxication, which are very different in their primary mechanism of inducing hepatotoxicity, it is suggested that protective mechanisms of andrographolide which are not specific to galactosamine or paracetamol toxicity may be responsible for the hepatoprotective activity of the compound.

After stroke, white matter integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption in mirror's regions of the contralateral hemisphere is associated with degree of functional impairment. Fourteen patients suffering right hemispheric focal stroke (S) and eighteen healthy controls (HC) underwent Diffusion Weighted Imaging (DWI) and neuropsychological assessment. The stroke patient group was divided into poor (SP; n = 8) and good (SG; n = 6) cognitive recovery groups according to their cognitive improvement from the acute phase (72 hours after stroke) to the subacute phase (3 months post-stroke). Whole-brain DWI data analysis was performed by computing Diffusion Tensor Imaging (DTI) followed by Tract Based Spatial Statistics (TBSS). Assessment of effects was obtained computing the correlation of the projections on TBSS skeleton of Fractional Anisotropy (FA) and Radial Diffusivity (RD) with cognitive test results. Significant decrease of FA was found only in right brain anatomical areas for the S group when compared to the HC group. Analyzed separately, stroke patients with poor cognitive recovery showed additional significant FA decrease in several left hemisphere regions; whereas SG patients showed significant decrease only in the left genu of corpus callosum when compared to the HC. For the SG group, whole brain analysis revealed significant correlation between the performance in the Semantic Fluency test and the FA in the right hemisphere as well as between the performance in the Grooved Pegboard Test (GPT) and the Trail Making Test-part A and the FA in the left hemisphere. For the SP group, correlation analysis revealed significant correlation between the performance in the GPT and the FA in the right hemisphere.

Hepatoprotective activity of Emblica officinalis (EO) and Chyavanaprash (CHY) extracts were studied using carbon tetrachloride (CCl(4)) induced liver injury model in rats. EO and CHY extracts were found to inhibit the hepatotoxicity produced by acute and chronic CCl(4) administration as seen from the decreased levels of serum and liver lipid peroxides (LPO), glutamate-pyruvate transaminase (GPT), and alkaline phosphatase (ALP). Chronic CCl(4) administration was also found to produce liver fibrosis as seen from the increased levels of collagen-hydroxyproline and pathological analysis. EO and CHY extracts were found to reduce these elevated levels significantly, indicating that the extract could inhibit the induction of fibrosis in rats.

BACKGROUND

Previous studies from our group and others have shown that cyclooxygenase-2 (COX-2) has an essential role in radiation-induced non-targeted responses and genomic instability in vivo. However, the signalling pathways involved in such effects remain unclear.

METHODS

A 1 cm(2) area (1 cm × 1 cm) in the lower abdominal region of gpt delta transgenic mice was irradiated with 5 Gy of 300 keV X-rays. Nimesulide, a selective COX-2 inhibitor, was given to mice for five consecutive days before irradiation. Changes in transforming growth factor-beta (TGF-β) and TGF-β receptor type-1 (TGFBR1) mediated signalling pathways, in the out of radiation field lung and liver tissues were examined.

RESULTS

While the plasma level of cytokines remained unchanged, the expression of TGF-β and its receptors was elevated in non-targeted lung tissues after partial body irradiation. In contrast to the predominant expression of TGF-β in stromal and alveolar cells, but not in bronchial epithelial cells, TGF-β receptors, especially TGFBR1 were significantly elevated in non-targeted bronchial epithelial cells, which is consistent with the induction of COX-2. The different expression levels of TGFBR1 between liver and lung resulted in a tissue specific induction of COX-2 in these two non-targeted tissues. Multiple TGF-β induced signalling pathways were activated in the non-targeted lung tissues.

CONCLUSIONS

The TGFβ-TGFBR1-COX-2 Signalling Pathway has a critical role in radiation-induced non-targeted response in vivo.

The hepatoprotective effects of the hot water (SRHW) and methanolic (SRM) extracts from the roots and stems of Salacia reticulata were examined using an oxidative stress-induced liver injury model. Both SRHW and SRM extracts (400 mg/kg, p.o.) significantly suppressed the increase in glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities in carbon tetrachloride (CCl4)-treated mice. These extracts also inhibited CCl4-induced thiobarbituric acid-reactive substance (TBA-RS) formation, which indicates increased lipid peroxidation in the liver. A good correlation (r=0.945, p<0.01) was observed between the amount of phenolic compounds in the extracts and their inhibitions of TBA-RS formation. The IC50 values of the extracts on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging were less than 10 microg/ml and the antioxidative activities of six phenolic compounds from the roots of S. reticulata were examined. Mangiferin, (-)-4'-O-methylepigallocatechin, and (-)-epicatechin-(4beta-->8)-(-)-4'-O-methylepigallocatechin, which a principal phenolic compounds, showed potent scavenging activity on DPPH radicals and their concentrations required for 50% reduction of 40 microM DPPH radicals were 5.9, 10, and 3.2 microM, respectively. On the other hand, against the CCl4-induced serum GOT and GPT elevations and TBA-RS formation in mice, mangiferin and (-)-4'-O-methylepigallocatechin showed potent activity at a dose of 100 mg/kg, but (-)-epicatechin-(4beta-->8)-(-)-4'-O-methylepigallocatechin did not. These results suggest that the antioxidative activity of the principal phenolic compounds is involved in the hepatoprotective activity of S. reticulata.

Type 2 Diabetes mellitus (T2DM) is an evident growing disease that affects different cultures throughout the world. T2DM occurs under the influence of three main factors: the genetic background, environmental and behavioral components. Obesity is strongly associated to the development of T2DM in the occident, while in the orient most of the diabetic patients are considered lean. Genetics may be a key factor in the development of T2DM in societies where obesity is not a recurrent public health problem. Herein, two different models of rats were used to understand their differences and reliability as experimental models to study the pathophysiology of T2DM, in two different approaches: the genetic (GK rats) and the environmental (HFD-induced obese rats) influences. GK rats were resistant to weight gain even though food/energy consumption (relative to body weight) was higher in this group. HFD, on the other hand, induced obesity in Wistar rats. White adipose tissue (WAT) expansion in this group was accompanied by immune cells infiltration, inflammation and insulin resistance. GK rats also presented WAT inflammation and insulin resistance; however, no immune cells infiltration was observed in the WAT of this group. Liver of HFD group presented fat accumulation without differences in inflammatory cytokines content, while liver of GK rats didn't present fat accumulation, but showed an increase of IL-6 and IL-10 content and glycogen. Also, GK rats showed increased plasma GOT and GPT. Soleus muscle of HFD presented normal insulin signaling, contrary to GK rats, which presented higher content of basal phosphorylation of GSK-3β. Our results demonstrated that HFD developed a mild insulin resistance in Wistar rats, but was not sufficient to develop T2DM. In contrast, GK rats presented all the typical hallmarks of T2DM, such as insulin resistance, defective insulin production, fasting hyperglycemia/hyperinsulinemia and lipid plasma alteration. Thus, on the given time point of this study, we may conclude that only GK rats shown to be a reliable model to study T2DM.

Macroautophagy/autophagy delivers damaged proteins and organelles to lysosomes for degradation, and plays important roles in maintaining tissue homeostasis by reducing tissue damage. The translocation of LC3 to the limiting membrane of the phagophore, the precursor to the autophagosome, during autophagy provides a binding site for autophagy cargoes, and facilitates fusion with lysosomes. An autophagy-related pathway called LC3-associated phagocytosis (LAP) targets LC3 to phagosome and endosome membranes during uptake of bacterial and fungal pathogens, and targets LC3 to swollen endosomes containing particulate material or apoptotic cells. We have investigated the roles played by autophagy and LAP in vivo by exploiting the observation that the WD domain of ATG16L1 is required for LAP, but not autophagy. Mice lacking the linker and WD domains, activate autophagy, but are deficient in LAP. The LAP-/- mice survive postnatal starvation, grow at the same rate as littermate controls, and are fertile. The liver, kidney, brain and muscle of these mice maintain levels of autophagy cargoes such as LC3 and SQSTM1/p62 similar to littermate controls, and prevent accumulation of SQSTM1 inclusions and tissue damage associated with loss of autophagy. The results suggest that autophagy maintains tissue homeostasis in mice independently of LC3-associated phagocytosis. Further deletion of glutamate E230 in the coiled-coil domain required for WIPI2 binding produced mice with defective autophagy that survived neonatal starvation. Analysis of brain lysates suggested that interactions between WIPI2 and ATG16L1 were less critical for autophagy in the brain, which may allow a low level of autophagy to overcome neonatal lethality. Abbreviations: CCD: coiled-coil domain; CYBB/NOX2: cytochrome b-245: beta polypeptide; GPT/ALT: glutamic pyruvic transaminase: soluble; LAP: LC3-associated phagocytosis; LC3: microtubule-associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; NOD: nucleotide-binding oligomerization domain; NADPH: nicotinamide adenine dinucleotide phosphate; RUBCN/Rubicon: RUN domain and cysteine-rich domain containing Beclin 1-interacting protein; SLE: systemic lupus erythematosus; SQSTM1/p62: sequestosome 1; TLR: toll-like receptor; TMEM: transmembrane protein; TRIM: tripartite motif-containing protein; UVRAG: UV radiation resistance associated gene; WD: tryptophan-aspartic acid; WIPI: WD 40 repeat domain: phosphoinositide interacting.

For the investigation of locoregional chemotherapy of liver neoplasms we developed a standardized animal model in the rat. Continuous infusion therapy or repeated bolus injections of FUDR or 5-FU were given via the hepatic artery, the portal vein or the vena cava in tumor-bearing animals. The efficacy of the treatment was determined by measuring the tumor volume 3 weeks after tumor cell implantation. For the evaluation of the local and systemic toxicity serum GOT, GPT, and total bilirubin were determined. DNA single strand breaks were assessed in isolated liver and bone marrow cells. Inhibition of colony formation of bone marrow stem cells was determined by CFU-C and CFU-S bioassay. A significant reduction of tumor growth was observed only after continuous infusion of FUDR via the hepatic artery. Systemic toxicity was lowest in this group for both compounds while the local liver toxicity was only slightly elevated.

There is overwhelming evidence for an association between impaired mitochondrial function and metabolic syndrome. Mitophagy, a process that selectively removes damaged mitochondria via a specialized form of autophagy, is essential for mitochondrial quality control (mitochondrial QC) and metabolic homeostasis. We thus addressed the potential role of defective mitophagy in the pathogenesis of metabolic disorders. Mice lacking Fundc1, a newly characterized mitophagy receptor, develop more severe obesity and insulin resistance when fed a high-fat diet (HFD). Ablation of Fundc1 results in defective mitophagy and impaired mitochondrial QC in vitro and in white adipose tissue (WAT). In addition, there is more pronounced WAT remodeling with more adipose tissue-associated macrophages infiltration, more M1 macrophage polarization and thus an elevated inflammatory response. Mechanistically, hyperactivation of MAPK/JNK leads to insulin insensitivity, which can be inhibited by knocking out Mapk8/Jnk1 in fundc1 KO mice. Our results demonstrate that dysregulated mitochondrial QC due to defective mitophagy receptor FUNDC1 links with metabolic disorders via MAPK signaling and inflammatory responses. Abbreviations: ATMs: adipose tissue macrophages; BAT: brown adipose tissue; BMDMs: bone marrow-derived macrophages; GOT1/AST: glutamic-oxaloacetic transaminase 1, soluble; GPT/ALT: glutamic pyruvic transaminase, soluble; H&E staining: hematoxylin and eosin staining; HFD: high-fat diet; LIR: LC3-interacting region; mitochondrial QC: mitochondrial quality control; mito-ROS: mitochondrial ROS; mtDNA: mitochondrial DNA; RT-PCR: real-time-PCR; T2D: type 2 diabetes; WAT: white adipose tissue.

We have demonstrated that carcinogen damage to DNA induces the production of cellular factors that act in trans to enhance the asynchronous replication of polyoma viral DNA. Exposure of a polyoma virus-transformed rat cell line to benzo[a]pyrene-7,8-diol-9,10-oxide (BPDE), the ultimate carcinogenic metabolite of benzo[a]pyrene, led to the accumulation of heterogeneously sized free viral DNA molecules which contain polyoma origin sequences as well as cellular sequences that flank the integrated viral DNA. When the sequence gpt was linked to the polyoma early region and transfected into rat cells, it underwent asynchronous replication in response either to direct treatment of the transfected cells with BPDE, or to fusion of untreated transfected cells with normal cells previously exposed to BPDE. Transient arrest of the cell cycle by hydroxyurea, isoleucine deprivation or methotrexate caused a slight enhancement of viral DNA replication when compared with BPDE. Both aphidicolin, an inhibitor of DNA polymerase alpha, and 3-aminobenzamide, an inhibitor of poly[ADP]ribosyl transferase, caused marked inhibition of BPDE-induced viral DNA synthesis. The induction of a trans-acting factor in response to damage of cellular DNA may be relevant to synergistic interactions between environmental chemicals and DNA viruses in cell transformation and to the general phenomenon of gene amplification.

Treatment of male Wistar rats with a single dose of lead nitrate caused a marked enlargement of the liver, which reached its maximum 3 days after the administration of the metal salt. This grossly anatomic effect was accompanied by biochemical changes such as an increase in total protein and DNA content, with a maximum at 3 and 4 days, respectively. A partial regression of liver weight and total DNA and protein content occurred 7 days after lead administration; a significant increase in DNA concentration was found after 1 week, while no variation in protein, when expressed as milligrams per gram liver, was observed in lead-treated rat liver. An increase in DNA synthesis, as monitored by the incorporation of labeled thymidine, was also observed. An enhancement in the specific radioactivity of DNA was evident at 24 hours and appeared maximal at 36 hours after the administration of lead nitrate. The ability of lead to stimulate liver cell proliferation was shown by a significant increase of cells entering mitosis, with a peak at 48 hours. This mitogenic stimulus occurred in parenchymal as well as in nonparenchymal cells, thus showing that this effect was not unique to a particular liver cell populations. No detectable cell necrosis, as monitored by histologic observation, was seen in the liver of lead-treated rats, thus indicating that the cellular proliferation induced by lead is not due to a regenerative response. Only a slight elevation in the levels of serum glutamate-pyruvate transaminase (GPT) was observed by biochemical analysis.

The nucleotide sequence was determined for the Escherichia coli region containing the gpt gene, which encodes the enzyme xanthine-guanine phosphoribosyl transferase (XGPRT; EC 2.4.2.22). Restriction enzyme and sequence analyses have allowed us to locate precisely the gpt gene (16.9-kDal XGPRT) with respect to other genes in this region, notably phoE. Genes gpt and phoE are pointing towards each other and are separated by about 1840 bp. Available sequence data and protein analyses [Overbeeke et al., J. Mol. Biol. 163 (1983) 513-522, and this paper] indicate the presence, between gpt and phoE, of two additional genes. These genes are oriented the same way as gpt and code for proteins of 49 and 15.7 kDal, respectively. By in vitro transcription with E. coli RNA polymerase and nuclease S1 analysis, we have identified a promoter upstream of gpt. The short intercistronic region between gpt and the 49-kDal protein gene contains a rho-independent termination signal that closely precedes and partially overlaps another promoter. It appears from these data that gpt transcription is essentially monocistronic, giving rise to RNA of approx. 555 nucleotides, whereas the 49-kDal and 15.7-kDal protein genes are transcribed from their own promoter.

We describe an immunoglobulin gene recombination indicator in which a specific rearrangement via deletion results in the acquisition of a dominant phenotype. The indicator consists of the Escherichia coli xanthine/guanine phosphoribosyltransferase (gpt) gene, whose translation is prevented by the presence of an upstream initiation codon out of frame with respect to the gpt coding sequence. Flanking this barrier initiation codon are the heptamer-spacer-nonamer recognition sequences from a kappa chain variable region (V kappa) and from a kappa chain joining region (J kappa). A proper V-J joint results in the deletion of the translational barrier and allows expression of the selectable marker. When tested by transfection into fibroblasts, no rearrangements were detected and the presence of the barrier initiation codon was sufficient to completely abolish gpt expression in these cells. Similarly, no rearrangements were detected after transfer of the test gene into myeloma cells. However, when the construct was introduced into the pre-B-cell line 38B9, greater than 80% of the transfected cells showed evidence of a specific rearrangement. These rearrangements were associated with the translation of gpt, although no selection for its expression was needed. DNA sequence analysis of six different V-J joints revealed that the rearrangement proceeded with a high degree of accuracy. These results indicate that only very minimal DNA sequences (21 base pairs 5' of the V heptamer and 4 base pairs 3' of its nonamer; less than 45 base pairs 5' of the J nonamer and 3' of its heptamer) are required for efficient rearrangement and provide formal proof that kappa gene segments can rearrange by a deletional mechanism.

We have used integrative pSV2 plasmids to learn how DNA lesions affect nonhomologous recombination with human chromosomes. Enhanced stable transformation of fibrosarcoma cells with a selectable gene was observed after chemical modification of the plasmid DNA; thus, cells transfected with plasmid pSV2-gpt carrying photoadducts of the cross-linking agent 4'-hydroxymethyl-4,5',8-trimethylpsoralen (HMT) yielded four- to sevenfold-higher levels of Gpt+ transformants than were obtained with untreated plasmid. The enhancement due to HMT interstrand cross-links was at least as great as that due to the monoadducts. DNA hybridization analysis indicated that the enhanced transformation frequency resulted from an increased number of cells carrying integrated plasmid sequences rather than from a higher copy number per transformant. The enhancement was not seen with a plasmid missing the sequences flanking the minimal simian virus 40 gpt transcription unit. Cotransfection with untreated and HMT-treated plasmids suggested that the HMT-containing DNA interacted preferentially with some cellular factor that promoted chromosomal integration of the plasmid DNA. It is concluded that (i) interstrand cross-linking as well as intrastrand DNA adducts promote nonhomologous recombination in human chromatin and (ii) DNA sequences flanking the selectable genes are the targets for such recombinational events.

Ricin a glycoprotein from the Ricinus communis seeds, is known to have diverse toxic effects on cells of different visceral organs. We have studied the hepatotoxicity, nephrotoxicity, and oxidative stress following i.p. administration of ricin (25 microg/kg) in Swiss albino male mice. The results of this study revealed that activities of various enzymes like glutamic pyruvic transaminase (GPT), alkaline phosphatase (ALP), gamma glutamyl transpeptidase (gamma-GT), and lactate dehydrogenase (LDH) were increased in plasma, liver, and kidney tissues indicating damage in liver and kidney. Blood urea level was also increased. However, blood creatinine and bilirubin were not altered. Lipid peroxidation increased to 49 and 25% in hepatic and renal tissue. Total non-protein sulfhydryl content decreased in plasma (12%), hepatic (29%), and renal (16%) tissues. Superoxide dismutase activity decreased significantly in liver (43%) and kidney (37%). The activity of glutatione peroxidase was also decreased. The decrease was more prominent in kidney than liver. A significant increase, 20 to 27% in the activity of catalase was observed in plasma, liver, and kidney. These results indicate that ricin produces hepatoxicity, nephrotoxicity, and oxidative damage at 24 h of post treatment. The hepatotoxicity was more prominent than nephrotoxicity.

In a previous study the BamHI-K fragment of Epstein-Barr virus DNA was shown to induce a nuclear antigen, Epstein-Barr virus nuclear antigen (EBNA), when cotransfected with the herpes simplex virus thymidine kinase gene into mouse LTK- cells. We have now inserted the BamHI-K fragment and a BamHI/HindIII subfragment, I1f , into shuttle vectors containing the origin of replication of simian virus 40. These plasmids have been introduced into COS-1, which are monkey kidney cells transformed by an origin-defective simian virus 40 genome. This expression system permitted rapid characterization of antigens, mRNAs, and proteins related to EBNA. The same-sized EBNA protein (approximately 78,000) was made after transfection with BamHI-K (5.2 kilobase pairs [kbp]) or the I1f subfragment (2.9 kbp). A deletion of about 600 bp occurred when the I1f fragment was propagated on the pSV2 plasmid in Escherichia coli. The deleted fragment gave rise to a smaller protein (approximately 52,000). These data provide evidence that EBNA is encoded by the 2.9-kbp I1f and is not an induced cellular protein. Nuclear antigen and polypeptide expression occurred equally well when the Epstein-Barr virus DNA was cloned on PSV2 -gpt or pSVOd . The latter plasmid lacks sequences allowing for efficient early gene transcription as well as splicing and polyadenylation signals which are present in pSV2 . Preliminary mapping of the EBNA gene transcripts demonstrated that two mRNAs (2.9 and 2.4 kilobases [kb]) are homologous to the I1f fragment. Taken together, the data suggest that the 2.9-kbp I1f fragment contains the structural gene for EBNA synthesis. COS-1 cells will thus provide a valuable system in which to analyze functional domains of the EBNA gene.

A recombinant capripoxvirus has been constructed containing a full-length cDNA of the fusion protein gene of rinderpest virus. The gene was inserted in the thymidine kinase gene of the capripox genome under the control of the vaccinia virus major late promoter p11 together with the Escherichia coli gpt gene in the opposite orientation under the control of the vaccinia early/late promoter p7.5. A vaccine prepared from this recombinant virus protected cattle against clinical rinderpest after a lethal challenge with a virulent virus isolate. In addition, the vaccine protected the cattle against lumpy skin disease.

Oxygen free radicals have been implicated as mediators of ischemia/reperfusion injury in a variety of organs. We investigated the role of oxidative injury and endogenous hepatic glutathione (GSH) in liver cell injury associated with complete hepatic ischemia and reperfusion. Forty-five minutes of complete hepatic ischemia followed by reperfusion caused an increase in serum GPT and a fall in hepatic GSH but no increase in hepatic lipid peroxidation products. Chemical depletion of hepatic GSH with diethyl maleate did not cause hepatocellular injury but augmented hepatic ischemia/reperfusion-induced SGPT release and promoted lipid peroxidation. Pretreatment with the selective, membrane-permeable oxygen radical scavenger dimethyl sulfoxide protected against the ischemia/reperfusion-induced drop in hepatic GSH but did not reduce SGPT release in normal rats. In rats sensitized to oxidative injury by depletion of endogenous GSH with diethyl maleate the oxygen radical scavenger protected against ischemia/reperfusion-induced lipid peroxidation and reduced the release of SGPT. These findings suggest that the rich hepatic supply with endogenous GSH has a crucial role in the protection against oxygen radical injury following short periods of total hepatic ischemia. Oxygen radical injury only occurs after depletion of these endogenous GSH stores.

Two cerebrosides isolated from Lycium chinense fruits have been characterized as 1-O-beta-D-glucopyranosyl-(2S, 3R,4E,8Z)-2-N-palmitoyloctadecasphinga-4,8-dienine+ ++ (1) and 1-O-beta-D-glucopyranosyl -(2S,3R,4E,8Z)-2-N-(2'-hydroxypalmitoyl)octadecasph inga-4,8-dienine (2). While 2 is already known, the structure of 1 was determined by spectral and chemical studies. Incubation of CCl4-intoxicated hepatocytes with 1 and 2, respectively, significantly reduced the levels of glutamic pyruvic transaminase (GPT) and sorbitol dehydrogenase (SDH) released by injured cells.

Isoelectric focusing and studies with 1-(2'-deoxy-beta-D-glucopyranosyl)thymine (GPT), a specific inhibitor of uridine phosphorylase activity, were used to determine the substrate specificities of mammalian pyrimidine nucleoside phosphorylases and their cleavage of 5-fluoro-2'-deoxyuridine (FdUrd). Isoelectric focusing profiles for the cytosol fractions from Ehrlich ascites cells and from Novikoff hepatoma cells each consisted essentially of one peak of nucleoside phosphorylase activity [isoelectric points (pl) 5.4 and 5.8, respectively] that cleaved both uridine and thymidine (dThd), as well as FdUrd. By contrast, cytosol fractions from HeLa (S3) cells, mouse liver, and normal human leukocytes each exhibited a major peak of activity (pl 4.6, 6.5, and 4.9, respectively) that cleaved only dThd and FdUrd, while mouse liver exhibited a second peak (pl 5.2) that cleaved primarily uridine. To distinguish clearly between (a) uridine phosphorylases that cleave primarily uridine and that are inhibited by GPT and (b)dThd phosphorylases that cleave only deoxynucleosides and that are not inhibited by GPT, we propose the term "uridine-deoxyuridine phosphorylases" to define those pyrimidine nucleoside phosphorylases that cleave both uridine and dThd and that are inhibited by GPT. On the basis of this definition and studies with GPT in nonfocused cytosol preparations, we conclude that FdUrd is cleaved to 5-fluorouracil by uridine-deoxyuridine phosphorylase activity in Ehrlich ascites cells and in Novikoff hepatoma cells, and by dThd phosphorylases in mouse liver, in normal human leukocytes, and in HeLa (S3) cells.