Similar Alteration Pattern Research Articles

Translational responses and oxidative stress of mussels experimentally exposed to Hg, Cu and Cd: One pattern does not fit at all

Certain metals, like Hg, Cu and Cd, are capable of down-regulating protein synthesis in several marine organisms, including Mytilus galloprovincialis. Nevertheless, due to the complexity of the environmental stress, it is difficult to evaluate the influence of individual metals on protein synthesis via field studies. To bypass this difficulty, experimental studies were carried out on M. galloprovincialis exposed in aquarium for 15 days to one of three selected metal salts, HgCl 2, CuCl 2 and CdCl 2. Polysome profile was determined in digestive gland extracts of the exposed mussels as a way of measuring the functional status of ribosomes, superoxide radical production and lipid peroxidation as indicators of oxidative stress, metallothionein content as a metal detoxification index, and superoxide dismutase activity as a free radicals-scavenging index. Exposure of mussels to Hg 2+ or Cu 2+ resulted in a concentration- and time-dependent decrease in the polysome content of digestive gland cells, which at 15th day of exposure and at the highest metal concentrations tested, was 32% and 19% of the control, respectively. Both metals, at the concentrations used (<40 μg/L), did not significantly influence the oxidative stress biomarkers. By contrast, Cd 2+ treatment significantly induced superoxide radical production and lipid peroxidation in digestive gland cells, hinting that mussels suffered from oxidative stress. Polysome levels in Cd 2+-exposed mussels were initially decreased by day 5 in digestive gland cells and then elevated to reach nearly the control levels by 15 days of exposure. Elevated protein synthesis was associated with significantly increased production of metallothioneins, whereas such increase was not recorded in Hg 2+- or Cu 2+-exposed mussels. Interestingly, the ribosome efficiency at initiating protein synthesis followed a similar pattern of polysome alterations, a fact suggesting that regulation of protein synthesis mainly occurred at the initiation phase of translation. Overall, these results suggest that the effect of each metal on protein synthesis is idiosyncratic and depends on its ability to induce specific cellular defense mechanisms against oxidative stress.

Nanotoxicology : An Emerging Discipline

Nanotoxicology refers to the study of the interactions of nanostructures with biological systems with an emphasis on elucidating the relationship between the physical and chemical properties of nanostructures with induction of toxic biological responses. Nanotoxicology is aimed at providing information on the potential toxicological effects, risk assessment and safety evaluation of nanostructured materials on human health. Nanoparticles present possible dangers, both medically and environmentally. They are also able to pass through cell membranes in organisms and their interactions with biological systems are relatively unknown. Animal studies have shown that nanoparticles can penetrate cells and tissues, move through the body and brain and cause biochemical damage. The greater chemical reactivity of nanomaterials result in increased production of reactive oxygen species which may contribute to similar patterns of cell injury and alterations at the molecular level by initiation, propagation and autocatalytic chain reactions. Intracellular signaling activation and inactivation of enzymes, stimulation, secretion and release of pro-inflammatory cytokines, chemokines and nuclear factor activation and alteration are also common events.

Systemic alteration of Cholesterol Homeostasis in experimental and natural scrapie

Alessandra Pani1, S. Vascellari1, C.D. Orru1, C. Abete1, A. Mandas2, S. Dessi2 1Department of Biomedical Science & Technology 2Department of Internal Medicine, University of Cagliari, Italy O the last few years a signifi cant amount of genetic, biochemical, and pharmacological data have indicated that prion disorders are associated with brain cholesterol alterations. At the molecular level, growing evidence indicate that the cholesterol–rich domains of plasma membrane (i.e. raft s) represent preferred sites of conversion of the cellular prion protein (PrPc) into pathogenic prion isoform(s) (PrPsc), and that alterations of membrane cholesterol, the main regulator of organization and function of raft domains, play a key role in prion pathophysiology. In this context, our studies showed that brains from mice and sheep infected with scrapie, as well as persistently prion-infected mouse neuroblastoma N2a cells, exhibit an increased content of cholesterol and an altered ratio of the intracellular cholesterol pools [i.e. free cholesterol (FC) vs. cholesterol esters (CE)], resulting in abnormal cytoplasmic accumulation of CE. Interestingly, we found that also cells from peripheral tissues [i.e. ex vivo cultures of skin fi broblasts and peripheral blood mononuclear cells (PBMCs)] of scrapie-infected sheep, show a similar pattern of cholesterol alterations. Th e biochemical cholesterol modifi cations were accompanied by changes in the expression levels of genes and gene-products involved in cholesterol esterifi cation and traffi cking [i.e. acyl-coenzymeA:cholesterol-acyltransferase (ACAT-1; up-regulated) and caveolin-1 (Cav-1; down-regulated)]. Altogether these data indicate that prion disorders are likely associated with major systemic alterations of the cholesterol homeostatic networks. In addition, in persistently prion-infected N2a cells, we found that drugs [i.e. everolimus, pioglitazone, Sandoz 58035, progesterone, verapamil] able to reduce the CE pool by diff erent mechanisms, were also able to inhibit the generation of the PK-resistant prion protein (PrPres) in a dose-response manner, and that strong synergistic anti-prion eff ects can be obtained with combinations of various cholesterol interfering drugs, apparently via restoration of cholesterol homeostasis in the infected cell. Although eff ectiveness of such drug combinations has yet to be proved in vivo, the enhanced anti-prion eff ect suggests that a rational design of drug combinations which interact at the cholesterol metabolism level, contributing to a better understanding of the complex relationship that links cholesterol metabolism to PrPsc biogenesis, may lead to the development of novel therapeutic and/or prophylactic approaches for the successful control of prion disorders.

Identification of a novel mitochondrial protein, short postembryonic roots 1 (SPR1), involved in root development and iron homeostasis in Oryza sativa

• A rice mutant, Oryza sativa short postembryonic roots 1 (Osspr1), has been characterized. It has short postembryonic roots, including adventitious and lateral roots, and a lower iron content in its leaves. • OsSPR1 was identified by map-based cloning. It encodes a novel mitochondrial protein with the Armadillo-like repeat domain. • Osspr1 mutants exhibited decreased root cell elongation. The iron content of the mutant shoots was significantly altered compared with that of wild-type shoots. A similar pattern of alteration of manganese and zinc concentrations in shoots was also observed. Complementation of the mutant confirmed that OsSPR1 is involved in post-embryonic root elongation and iron homeostasis in rice. OsSPR1 was found to be ubiquitously expressed in various tissues throughout the plant. The transcript abundance of various genes involved in iron uptake and signaling via both strategies I and II was similar in roots of wild-type and mutant plants, but was higher in the leaves of mutant plants. • Thus, a novel mitochondrial protein that is involved in root elongation and plays a role in metal ion homeostasis has been identified.

Long-Term Kinetics of Cytokine Responses in Human Tears After Penetrating Keratoplasty

This was a kinetic study of inflammatory cytokine levels in postoperative tear samples from penetrating keratoplasty (PKP) patients with or without corneal rejection. In a prospective design, nonstimulated tears were collected from the affected eyes of 12 patients at regular intervals for 12-14 months following PKP. Nine patients retained clear grafts, whereas three suffered endothelial rejection of the corneal graft within 14 months. The concentrations of the cytokines IL-1beta, IL-6, TNF-alpha, IL-8, IL-10, and IL-12p70 were measured via cytometric bead array technology. The postoperative concentrations of the cytokines in the tears varied among the patients, but exhibited similar alteration patterns in each eye tested. The concentrations of IL-6 and IL-8 were significantly higher (P = 0.009 and P = 0.01, respectively), whereas those of IL-10, TNF-alpha, and IL-12p70 were significantly lower (P = 0.008, P = 0.006, and P = 0.0009, respectively) in the tear samples from the patients with corneal rejection as compared with those with uncomplicated corneal grafts. The ratios IL-6/IL-10 and IL-8/IL-10 were significantly higher (P = 0.0231 and P = 0.015, respectively), and TNF-alpha/IL-10 was significantly lower (P = 0.045) throughout the examination period in the patients with endothelial rejection. The enhanced release of IL-6 and IL-8 into the tears of patients with corneal graft rejection concomitant with decreased concentrations of IL-10, TNF-alpha, and IL-12p70 may possibly serve as an indicator of the rejection process. However, due to the large variation in the cytokine concentrations, the observed changes in tear composition do not categorically predict the final graft outcome.

Increased oxidative/nitrosative stress and decreased antioxidant enzyme activities in prostate cancer

Objectives The study was aimed to evaluate the oxidative/nitrosative stress status in prostate cancer (CaP) and benign prostatic hyperplasia (BPH). Design and methods 312 men from two different populations were included: 163 men from Macedonia (73 CaP patients, 67 BPH patients and 23 control subjects) and 149 men from Turkey (34 prostate cancer patients, 100 BPH patients and 15 control subjects). We measured erythrocyte malondialdehyde (MDA) levels, erythrocyte activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPX) and catalase (CAT); plasma nitrite/nitrate (NO 2 −/NO 3 −), cGMP and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels. Results A similar pattern of alteration in the oxidative/nitrosative stress-related parameters was found in both, Macedonian and Turkish studied samples: higher MDA concentrations with lower GPX and CuZn-SOD activities in CaP patients versus controls and BPH groups. The CAT activity was decreased in the CaP patients versus controls in the Turkish studied sample. Furthermore, CaP patients had increased plasma NO 2 −/NO 3 − and cGMP levels versus controls and BPH groups in both studied samples. Conclusions This study has confirmed an imbalance in the oxidative stress/antioxidant status and revealed an altered nitrosative status in prostate cancer patients.

Targeting CD24 for Treatment of Colorectal and Pancreatic Cancer by Monoclonal Antibodies or Small Interfering RNA

CD24 is a potential oncogene reported to be overexpressed in a large variety of human malignancies. We have shown that CD24 is overexpressed in 90% of colorectal tumors at a fairly early stage in the multistep process of carcinogenesis. Anti-CD24 monoclonal antibodies (mAb) induce a significant growth inhibition in colorectal and pancreatic cancer cell lines that express the protein. This study is designed to investigate further the effects of CD24 down-regulation using mAb or small interfering RNA in vitro and in vivo. Western blot analysis showed that anti-CD24 mAb induced CD24 protein down-regulation through lysosomal degradation. mAb augmented growth inhibition in combination with five classic chemotherapies. Xenograft models in vivo showed that tumor growth was significantly reduced in mAb-treated mice. Similarly, stable growth inhibition of cancer cell lines was achieved by down-regulation of CD24 expression using short hairpin RNA (shRNA). The produced clones proliferated more slowly, reached lower saturation densities, and showed impaired motility. Most importantly, down-regulation of CD24 retarded tumorigenicity of human cancer cell lines in nude mice. Microarray analysis revealed a similar pattern of gene expression alterations when cells were subjected to anti-CD24 mAb or shRNA. Genes in the Ras pathway, mitogen-activated protein kinase, or BCL-2 family and others of oncogenic association were frequently down-regulated. As a putative new oncogene that is overexpressed in gastrointestinal malignancies early in the carcinogenesis process, CD24 is a potential target for early intervention in the prevention and treatment of cancer.

Isotonic fatigue in laminin α2–deficient dy/dy dystrophic mouse diaphragm

Laminin alpha2 deficiency causes approximately 50% of human congenital muscular dystrophies. Muscle in the corresponding dy/dy mouse model has reduced force but increased fatigue resistance during isometric contractions. To determine whether a similar pattern of alterations is present during isotonic contractions, dy/dy diaphragm was studied in vitro. During 20% load, dystrophic diaphragm had significantly reduced shortening, shortening velocity, work and power deficits, which persisted during the fatigue-inducing stimulation. In contrast, during 40% load, isotonic contractile performance of diseased muscle was impaired only mildly and only for some contractile parameters. At both loads, rate of isotonic fatigue when expressed relative to initial contractile values was similar for dystrophic and normal muscle, or in some instances slightly higher for dystrophic muscle. Therefore, fatigue resistance is considerably impaired during isotonic contractions relative to that reported previously for isometric contractions. This has important implications for increased susceptibility to respiratory failure in laminin alpha2-deficient muscular dystrophy.

Benzo (a) pyrene-induced human embryo lung cell cycle alterations through positive regulation of mitogen-activated protein kinase signal pathways

To study the effects of benzo(a)pyrene (BaP) on the cell cycle distribution and activities of mitogen-activated protein kinase (MAPK) signal molecules (ERK1/2, JNK1/2 and p38) in human embryo lung cells (HELF), and to investigate the relationship between alterations of MAPK protein phosphorylation and the cell cycle distributions. The phosphorylation of MAPK were induced by exposing HELF cells to BaP at 0.1, 0.5, 2.5 and 12.5 micromol/L. The phosphorylation and protein expression levels of ERK1/2, JNK1/2 and p38 were determined through western-blotting assay. And the flow cytometry assay was used to measure the cell cycle effects in HELF cells after treatment with 2.5 micromol/L BaP for 24 h. The phosphorylation levels of ERK1/2, JNK1/2 and p38 were significantly increased through BaP exposure. In addition, the phosphorylation of these three MAPKs has similar alteration pattern. We found that exposure of cells to 2.5 microM of BaP for 24 h resulted in a decrease of G(0) and G(1) population by 11.9% (F = 41.38, P < 0.01) and an increase of S population by 17.2% (F = 68.13, P < 0.01). Three chemical inhibitors of MAPK (AG126, SP600125 and SB203580) could significantly inhibit the cell cycle alteration because of BaP treatment. ERK1/2, JNK1/2 and p38 could positively regulate the BaP independently induced cell cycle alterations.

Close association between HER-2 amplification and overexpression in human tumors of non-breast origin

AbstractThe relationship between HER-2 overexpression and gene amplification is well evaluated in breast cancers but remains unclear or controversial in many other tumor entities. Therefore, we tested the HER-2 status in more than 120 different tumor entities. 5751 tumor samples were analyzed on TMAs by immunohistochemistry (Hercept-Test, DAKO) and fluorescence in situ hybridization (PathVysion, Abbott-Vysis) under highly standardized conditions. HER-2 overexpression (score 2/3+) and amplification occurred most often in breast cancers but was also seen in 18 other tumor entities including cancers of the urinary bladder (amplification in 14.3%, overexpression in 6.7%), stomach (8.3/4.9%), endometrium (6.6/6.8%), lung (2.8/3.1%) and ovary (2.3/1.2%). Remarkably, a strong association between overexpression and amplification was seen in all examined cancer entities. Trastuzumab therapy is highly efficient in HER-2 amplified breast cancer both in metastatic disease and as an adjuvant therapy. A variety of other tumor entities including frequent neoplasms and cancers with often limited therapeutic options have similar patterns of HER-2 alterations as observed in breast cancer (ie high overexpression due to high level gene amplification). Such tumor entities should be carefully evaluated for a possible utility of trastuzumab treatment.

Clinical application of array-based comparative genomic hybridization to define the relationship between multiple synchronous tumors

Array-based comparative genomic hybridization (CGH) is a technique that allows genome wide screening of gains and losses in DNA copy number. In cases where multiple tumors are encountered, this genetic technique may prove useful in differentiating new primary tumors from recurrences. In this case report, we used array-based CGH to examine the genomic relationships among two leiomyosarcomas and two breast cancers in the same patient, three of which were diagnosed synchronously. Array-based CGH was performed on the four tumor samples using random prime amplified microdissected DNA. Samples were hybridized onto bacterial artificial chromosome arrays composed of approximately 2400 clones. Patterns of alterations within the tumors were compared and genetic alterations among the leiomyosarcomas and breast lesions were found. Overall, three distinct genetic profiles were observed. While the two leiomyosarcomas shared a similar pattern of genetic alterations, the two invasive breast lesions did not. The nearly identical pattern of genetic alterations belonging to the two metachronous leiomyosarcomas confirmed metastatic recurrence while the two different genetic profiles of the invasive ductal carcinomas suggest that the two lesions represented two distinct foci of multifocal disease rather than clonal extension of the primary tumor. We conclude that genetic analysis by array-based CGH can clearly elucidate the relationships between multiple tumors and may potentially serve as an important clinical tool.

Alteration and breakdown of xenotime-(Y) and monazite-(Ce) in granitic rocks of the Western Carpathians, Slovakia

In the granitic rocks of the Western Carpathians, xenotime-(Y) occurs both as a late-stage magmatic mineral, and as a secondary post-magmatic phase. Magmatic xenotime occurs with monazite and displays minor compositional zonation involving Si, Th and U. The source of elements for the formation of secondary xenotime-(Y) in the granitic rocks results from leaching of P and (Y+REE), mainly from zircon and apatite. Both xenotime-(Y) and monazite-(Ce) are unstable during fluid-activated overprinting. Low temperature alteration of monazite in S-type granites leads to the formation of apatite enriched in the britholite component, but low to medium grades of metamorphism result in the formation of apatite and LREE enriched epidote (partly allanite) as a corona enclosing the monazite-(Ce) core. Xenotime-(Y) shows a similar alteration pattern, but with different REE distributions within the products. At greenschist/amphibolite facies, rims of secondary Y-rich apatite and Y-rich epidote form around xenotime-(Y). In low-Ca granites however, apatite is missing from this alteration assemblage as xenotime-(Y) breaks down directly to Y-enriched epidote. The relative mobilities of the heavy and light REE are different during breakdown of monazite and xenotime. The fluid responsible for the breakdown of monazite and xenotime contains elements released from alteration of anorthite (Ca) and biotite (Si, Al and F).

Fluorescence in situ hybridization analysis of matched primary tumour and lymph-node metastasis of D1 (pT2-3pN1M0) prostate cancer.

To describe the chromosomal numerical changes present in primary prostate tumours and their matched lymph-node metastases, to identify a clonal cell migration process which could account for the metastatic behaviour. Twenty-eight cases of unsuspected stage D1 (pT2-3pN1M0) prostate cancer were detected among patients who had a radical prostatectomy for clinically localized prostate cancer. Fluorescence in situ hybridization (FISH), using centromeric probes to enumerate chromosomes 7, 8, 10 and 12, was used to assess numerical chromosomal changes. FISH analysis was used on isolated nuclei obtained from matched primary tumours and their lymph node metastases. Of the 28 suitable cases it was possible to complete the study in 18 pairs of matched tissues; the remainder were excluded because of insufficient tissue or poor preservation of at least one of the tissues. There was cytogenetic change (aneuploidy) in 16 of the 18 primary tumours, the most common being monosomy 8, detected in 14, followed by trisomy 7, in 13 aneuploid tumours. All lymph node metastases were aneuploid by FISH. As in the primary tumours, monosomy 8 and trisomy 7 were the most common cytogenetic alterations, in 13 and 15 of the lymph node tissues. FISH analysis showed a high correlation (83%) in the cytogenetic pattern of changes between the primary tumours and their lymph node metastases. Moreover, a similar number of cells had the most common aneusomies when comparing prostate and the lymph node tissues. These results show a similar pattern of cytogenetic alteration in the primary tumour and its lymph node metastasis, characterized by the frequent presence of trisomy 7 and monosomy 8, suggesting that clonal cell selection is not involved in the metastatic process.

Metabolic Effects of Infection on Protein and Energy Status

A review of some of the seminal studies of metabolism during various infections indicates that similar patterns of metabolic alterations occur during these illnesses. This patterned metabolic array occurs whether the infection is caused by a gram-positive or a gram-negative bacterium, a rickettsia or a virus, or is respiratory or systemic. In all instances, the previously healthy host responds to infection with cytokine-mediated alterations that appear to occur in proportion to the infectious challenge and to the likelihood of death. These alterations also can occur in the vaccinated host, if the infectious challenge is sufficiently great. Because of their widespread occurrence and seemingly ingrained status, these metabolic alterations may be presumed to be of survival benefit to the host. Whether this patterned array of metabolic sequelae is of benefit to the host, or even to the species, its widespread and systematic occurrence allows it to be of value in assessing the safety and efficacy of vaccines and drugs to prevent or treat a wide variety of infections. In this era of bioterrorism, wherein drugs and vaccines may have to be approved for human use without clinical trials and solely on the basis of animal data, these cytokine-mediated metabolic sequelae can aid in the rational selection of drug and vaccine candidates.

Effects of α-ketoglutarate on antioxidants and lipid peroxidation products in rats treated with ammonium acetate

The effects of α-ketoglutarate (α-KG) on hyperammonemia induced by ammonium acetate were studied biochemically in experimental rats. The levels of circulatory urea and non-protein nitrogen increased significantly in rats treated with ammonium acetate and decreased significantly in rats treated with α-KG and ammonium acetate. In liver and kidney tissues, similar patterns of alterations across groups were observed in the levels of thiobarbituric acid-reactive substances and lipid profile variables (free fatty acids, triacylglycerols, phospholipids, and cholesterol). Further, enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) and non-enzymatic (reduced glutathione) antioxidants in both tissues decreased significantly in rats treated with ammonium acetate and increased significantly in rats treated with α-KG and ammonium acetate. The biochemical alterations during α-KG treatment might have been due to 1) the detoxification of excess ammonia, 2) participation in the non-enzymatic oxidative decarboxylation during hydrogen peroxide decomposition, and 3) enhancement of the proper metabolism of fats that could suppress oxygen radical generation and thus prevent lipid peroxidative damages in rats.

Evaluation of a 15-Day Screening Assay Using Intact Male Rats for Identifying Steroid Biosynthesis Inhibitors and Thyroid Modulators

An in vivo screening assay using intact adult male rats has been evaluated for its ability to detect four endocrine-active compounds (EACs) via oral (gavage) administration. The test compounds included the aromatase inhibitor fadrozole (FAD), the testosterone biosynthesis inhibitor ketoconazole (KETO), and the thyroid modulators phenobarbital (PB) and propylthiouracil (PTU). Three of the test compounds (KETO, PB, and PTU) have been previously evaluated in the 15-day intact male assay with compound administration via intraperitoneal injection (ip). For the current studies, male rats were dosed for 15 days via oral gavage and euthanized on the morning of test day 15. The endpoints evaluated included final body and organ weights (liver, thyroid gland, testes, epididymides, prostate, seminal vesicles with fluid, accessory sex gland unit [ASG]), serum hormone concentrations (testosterone [T], estradiol [E2], dihydrotestosterone [DHT], luteinizing hormone [LH,] follicle stimulating hormone [FSH], prolactin [PRL], T(3), T(4), thyroid stimulating hormone [TSH]), and histopathology of the testis, epididymis, and thyroid gland; positive results for each endpoint are described below. In addition, an evaluation of immune system endpoints (humoral immune function, spleen and thymus weights, and spleen cell number) was conducted on a subset of animals dosed with either KETO or PB. FAD and KETO decreased the weights for the androgen-dependent tissues and caused similar patterns of hormonal alterations (decreased serum T and DHT; increased serum FSH and/or LH). In addition, KETO caused spermatid retention. For FAD and KETO, effects on thyroid parameters were not indicative of thyroid toxicity. PB and PTU caused thyroid effects consistent with thyroid modulators (increased thyroid weight, decreased serum T(3) and T(4), increased serum TSH, thyroid follicular cell hypertrophy/hyperplasia, and colloid depletion). In addition, PB increased relative liver weight and altered reproductive hormone concentrations (decreased serum DHT, PRL, LH; increased serum E2). Orally administered KETO and PB did not alter the primary humoral immune response to sheep red blood cells (SRBC), although spleen weights were increased at the highest doses for both compounds. In the current study, all four test substances were identified as endocrine-active. The effects that were observed in the current study via oral (gavage) compound administration were similar to the responses that were observed by the ip route in previous studies for KETO, PB, and PTU. Overall, the sensitivity (i.e., the dose required to elicit similar magnitude responses) between the ip and oral routes of administration were similar for the three EACs that were examined by both routes of administration. This article, in addition to the > 20 compounds that have already been examined using the 15-day intact male assay, supports this assay as a viable screening assay for detecting EACs, and also illustrates that the ability to identify EACs using the intact male assay will be equivalent regardless of the route of compound administration.

Effects of Ornithine α-Ketoglutarate on Circulatory Antioxidants and Lipid Peroxidation Products in Ammonium Acetate Treated Rats

The effects of ornithine α-ketoglutarate (OKG) on ammonium acetate induced hepatotoxicity were studied biochemically in rats. The levels of urea, nonprotein nitrogen, and thiobarbituric acid reactive substances were significantly increased in ammonium acetate treated rats; these levels were significantly decreased in rats treated with ammonium acetate and OKG. Similar patterns of alterations were observed in the levels of free fatty acids, triglycerides, and phospholipids. Furthermore, nonenzymatic antioxidants (vitamins C and E) were significantly decreased in ammonium acetate treated rats, when compared with control rats, and increased in OKG and ammonium acetate treated rats. The biochemical alterations during OKG treatment could be (1) by detoxifying excess ammonia; (2) by participating in nonenzymatic oxidative decarboxylation in the hydrogen peroxide decomposition process, and (3) by enhancing the proper metabolism of fats which could suppress oxygen radical generation and thus prevent the lipid peroxidative damages in rats.

TP53 mutations, amplification of P63 and expression of cell cycle proteins in squamous cell carcinoma of the oesophagus from a low incidence area in Western Europe.

In Europe, high incidence rates of oesophageal squamous cell carcinoma (SCCE) are observed in western France (Normandy and Brittany) and in north-eastern Italy. Analysis of TP53 mutations in tumours from these regions has shown a high prevalence of mutations at A:T basepairs that may result from DNA damage caused by specific mutagens. However, the spectrum of TP53 mutations in regions of low incidence is unknown. We report here TP53 mutation analysis in 33 SCCE collected in Lyon, an area of low incidence. These tumours were also examined for MDM2 and P63 amplification, and for expression of p16INK4a/CDKN2a, cyclin E, p27Kipland Cox2. TP53 mutations were detected in 36% of the cases (12/33). In contrast with regions of high incidence, the mutation spectrum did not show a high prevalence of mutations at A:T base pairs. P63 was amplified in 5/32 cases tested (15.5%). No amplification of MDM2 was found. Expression studies revealed frequent loss of p16INK4a/CDKN2a(46%) and p27Kipl(25%) expression, and frequent overexpression of Cyclin E (70%) and Cox2 (42%). Overall, these results indicate that in Europe, SCCE from areas of high and low incidence present a similar pattern of molecular alterations but differ by the type of TP53 mutations. © 2001 Cancer Research Campaign http://www.bjcancer.com

Hepatocellular oxidative DNA injury induced by macrophage-derived nitric oxide

Previous studies have indicated that splenic macrophages migrate into the liver and play a role in endotoxin-induced hepatic damage. The present study was designed to elucidate the mechanisms of hepatocyte injury induced by activated splenic macrophages, focusing especially on endogenously released NO and oxidative DNA alterations in hepatocytes. Splenic macrophages isolated from Wistar rats were incubated with either lipopolysaccharide (LPS) or interferon-γ (IFN-γ) and cocultured with hepatocytes. Nitrite and nitrate levels in the culture medium were measured, and inducible-type NO synthase (iNOS) and nitrotyrosine were determined by immunofluorescence staining. The ratio of 8-hydroxy-deoxyguanosine (8-OH-dG) to deoxyguanosine (dG) was measured by high-performance liquid chromatography, and single-stranded DNA in hepatocytes was detected with acridine orange. NO release and nitrotyrosine expression in hepatocytes increased after 8 h of coculture with activated macrophages, and this coculture also induced increases in the 8-OH-dG/dG ratio and single-stranded DNA in the hepatocytes. These alterations were attenuated by superoxide dismutase (SOD) and NO synthesis inhibitors. A similar pattern of alterations was observed in hepatocytes incubated with SIN-1, and these changes were also prevented by SOD. These results suggest that activated macrophage-derived NO and its oxidative metabolite, peroxynitrite, play key roles in hepatocyte injury during inflammation, and cause subsequent DNA damage in surviving hepatocytes.

A study of visual and auditory verbal working memory in schizophrenic patients compared to healthy subjects.

Impaired working memory (WM) performance is considered as a central feature of schizophrenia. Divided into two components, verbal and spatial, WM has been shown to involve frontal and parietal regions. Verbal WM can be tested either visually or aurally. The present study aimed to test schizophrenic patients in both visual and auditory verbal WM in order to assess a possible distinct pattern of alteration of these two modalities. Twenty-four schizophrenic patients and 24 healthy controls were compared with 2-back continuous visual and auditory verbal WM testing. Both groups were also tested on a neuropsychological battery including Wisconsin Card Sorting Test (WCST). Schizophrenic patients were less efficient in both verbal WM tests. When taking age and educational level as covariates and both WM modalities as dependent variables, there was no differential effect of modalities across groups. In further exploratory analyses, partial correlations brought association between verbal WM and psychosocial adaptation, WCST and length of illness. These results suggest a similar pattern of alteration of both modalities of verbal WM in schizophrenic patients. The implications of this finding are discussed.