The Neuromelanin of Human Substantia Nigra: Physiological and Pathogenic Aspects

Neuromelanin (NM) accumulates as a function of age in normal human substantia nigra (SN) but is relatively depleted in the SN of patients with Parkinson disease (PD). Several studies have been performed to further our understanding of the role of NM in neuronal aging and neurodegenerative mechanisms of PD. To this purpose, NM from human SN was isolated and its structure and molecular interactions were investigated. Cysteinyl-dopamine was shown to be one precursor of NM synthesis. A striking affinity of NM for specific metals, lipids, drugs and pesticides was found in vitro, and in animal and human brain postmortem studies. Because of these affinities, NM seems to play a protective role in the human brain by blocking toxic molecules. On the other hand, experiments in cell culture indicate that NM can activate microglia, eliciting the release of cytotoxic factors that can induce neurodegeneration.

RNA-mediated interference indicates that SEL1L plays a role in pancreatic beta-cell growth

The specificity of SEL1L expression and promoter activity for the pancreatic cell population, its chromosomal location, as well as its similarities to the yeast Hrd3p protein, a component of HRD complex which is responsible for endoplasmic reticulum (ER)-associated degradation of numerous ER-resident proteins, prompted us to study its effects on beta cell function. In this study we show that lowering SEL1L expression, by using the short interfering RNAs technology as well as antisense transfection, resulted in severe perturbation of betaTC-3 growth and metabolic activity. We hypothesize that SEL1L may exert its function by protecting the cells from ER stress and could counteract immune responses.

Mutations of the T-cell receptor constant region after in utero stem cell transplantation

Like the immunoglobulin genes, the T-cell receptor genes are generated by rearrangements of non-contiguous genomic V, D and J regions, but unlike the immunoglobulin genes, somatic hypermutation is an infrequent event in T-cell receptor genes. Here, we describe the occurrence of spontaneous mutations in the constant regions of the T-cell receptor beta chains of T lymphocytes obtained from two babies who underwent in utero transplantation because of severe combined immunodeficiency. In view of the fact that in babies receiving transplants before birth, hematopoietic chimerism is consistently present, the lymphocytes are likely to be under chronic activation, which may represent a relevant biologic stimulus for generating the observed T-cell receptor hypermutation. This possibility is supported by the finding that the highest number of mutations was identified in clonally expanded T cells. These results provide further support indicating that hypermutation of the T-cell receptor genes may indeed occur, given the necessary conditions.

Reconstitution of T-cell compartment after in utero stem cell transplantation: analysis of T-cell repertoire and thymic output

BACKGROUND AND OBJECTIVES

In utero transplantation of hematopoietic stem cells allows immune reconstitution of fetuses with severe combined immunodeficiency. The objective of this work was to study the quality of T-cell reconstitution following this procedure.

DESIGN AND METHODS

We evaluated the kinetics and extent of T-cell reconstitution in five infants with severe combined immune deficiency (SCID), three with a B+ and two with a B- phenotype, who received haploidentical stem cell transplantation before birth. To this end, we measured the frequency of T-cell receptor excision circles (TREC) and the diversity of the T-cell repertoire.

RESULTS

In utero transplantation led to engraftment of donor-derived T lymphocytes which attained normal numbers in four infants, who are in good health. In the three patients with a B+ phenotype, generation of a heterogeneous T-cell repertoire was associated with development of TREC levels comparable to those of SCID patients treated by post-natal transplantation and of healthy babies. Of the two patients with a B- phenotype, one developed mixed T-cell chimerism and a substantial number of circulating T cells, associated with a variable heterogeneity of the T-cell repertoire; TREC levels were normal soon after birth, but declined thereafter. The remaining B- patient remained lymphopenic with a skewed T-cell repertoire and very low TREC levels. This patient eventually required transplantation from a matched unrelated donor at 5 years of age, but died of EBV-related lymphoproliferative disease.

INTERPRETATION AND CONCLUSIONS

These data indicate that in utero transplantation of fetuses with B+ SCID allows generation of newly diversified T lymphocytes and ensures long-term reconstitution of cell-mediated immunity.

Association of rat8 with Fyn protein kinase via lipid rafts is required for rat mammary cell differentiation in vitro

We previously identified rat8 in the pathway involved in epithelial cell differentiation that occurs in the rat mammary gland at pregnancy when tubules and alveoli are formed. rat8, which encodes an IFN-inducible membrane protein, is the rat homologue of the mouse gene fragilis. By differential detergent extraction and isopycnic sucrose density gradients, we show that rat8 protein is associated to lipid membrane domains together with Lyn and Fyn, members of the Src tyrosine kinase family. We also show that recruitment of rat8 to lipid membrane domains is a necessary step in mammary epithelial cell differentiation. Immunoprecipitation analysis, performed with an anti-Fyn protein antibody, shows that rat8 was present in the Fyn immunoprecipitate. Antisense oligonucleotides, used to inhibit Fyn protein expression, block mammary cell differentiation. Taken together, these results suggest that the functional interaction, via lipid membrane domains, of rat8 and Fyn proteins is required for mammary cell differentiation. Therefore, rat8, like fragilis, may be involved in developmental decisions and the demarcation of a subset of cells in the mammary gland that cause epithelial cells to develop into a network of tubuloalveolar structures involved in secretion.

Identification of a region within SEL1L protein required for tumour growth inhibition

The ectopic expression of the entire SEL1L cDNA significantly reduces the proliferate activity and aggressive behavior of the human breast carcinoma cell line MCF-7. However, the mechanism responsible for this biological effect remains unclear. A study was initiated to define those regions within SEL1L conferring such antiproliferative properties. Here we report that the region between amino acid residues 659-794 contains a functionally relevant domain since a deletion mutant impairs SEL1L's ability to suppress tumor cell growth. This region contains the Hrd3 motif, tetratricopeptide (TPR)-like SEL1 repeat, a transmembrane region, and a proline-rich tail.

Synergistic effect of apolipoprotein E polymorphisms and cigarette smoking on risk of ischemic stroke in young adults

BACKGROUND AND PURPOSE

The effect of apolipoprotein E (APOE) polymorphisms on stroke risk may be influenced by the coexistence of modifiable predisposing conditions. We explored the interactions of APOE genotypes and conventional risk factors in a case-control study of young adults with cerebral infarct.

METHODS

We analyzed 124 consecutive patients (age, 34.7+/-7.3 years) and 147 age- and sex-matched controls. APOE genotypes were determined by restriction fragment-length polymorphism analysis.

RESULTS

The prevalence of the epsilon4 allele and epsilon34 genotype was slightly higher in cases than in controls (0.125 versus 0.071 and 0.242 versus 0.136, respectively). Carriers of the epsilon34 genotype and epsilon4 allele were associated with an increased risk of stroke on multivariate analysis compared with the epsilon33 genotype and non-epsilon4 carriers, respectively (odds ratio [OR], 2.29; 95% confidence interval [CI], 1.10 to 4.76; and OR, 2.27; 95% CI, 1.13 to 4.56). ORs for stroke were 2.99 (95% CI, 1.64 to 5.45), 2.69 (95% CI, 1.25 to 5.77), and 5.39 (95% CI, 1.59 to 18.30) for smokers with the epsilon33 genotype, nonsmokers with the epsilon34 genotype, and smokers with the epsilon34 genotype, respectively, compared with nonsmokers with the epsilon33 genotype. Similar results were obtained when epsilon4 carriers and non-epsilon4 carriers were compared in the same interaction model. No significant interaction between APOE and hypertension was found.

CONCLUSIONS

In young adults, the APOE epsilon4 allele and cigarette smoking act synergistically, increasing an individual's propensity to have a cerebral ischemic event. This finding may help in determining an individual's predisposition to stroke and more targeted preventive interventions.

Effect of HAART on SEN virus infected HIV positive patients

Since it has been demonstrated that concomitant infections could influence the outcome of antiviral treatment, we investigated whether the presence of SENV infection may interfere with highly active antiretroviral therapy (HAART) in HIV+ coinfected patients. In spite of persistent fluctuations in SENV-A positivity we could not find any correlation between SENV-DNA and the immunological and virologic parameters found in the patients, suggesting SENV has no apparent clinical relevance during highly active antiretroviral therapy.

[Hypoparathyroidism following total thyroidectomy: prognostic value of intraoperative parathyroid hormone assay]

Transient and definitive hypoparathyroidism represent a frequent complication after thyroid surgery. Recently some authors proposed the use of intraoperative parathyroid hormone assay for the rapid detection of this complication. In this paper the authors describe the data obtained from 42 total thyroidectomies with intraoperative measurements of parathyroid hormone. When parathormone decrement was over 75% during thyroidectomy, the hypocalcemic symptomatology was found in all cases during postoperative observation. The authors emphasize intraoperative PTH dosage for immediate identification of patients at risk for postoperative hypoparathyroidism. In this cases parathyroid autotransplantation is suggested to prevent postoperative hypoparathyroidism.

Identification of New Mutations of the HFE, Hepcidin, and Transferrin Receptor 2 Genes by Denaturing HPLC Analysis of Individuals with Biochemical Indications of Iron Overload

Background: Hereditary hemochromatosis is a recessive disorder characterized by iron accumulation in parenchymal cells, followed by organ damage and failure. The disorder is mainly attributable to the C282Y and H63D mutations in the HFE gene, but additional mutations in the HFE, transferrin receptor 2 (TfR2), and hepcidin genes have been reported. The copresence of mutations in different genes may explain the phenotypic heterogeneity of the disorder and its variable penetrance.

Methods: We used denaturing HPLC (DHPLC) for rapid DNA scanning of the HFE (exons 2, 3, and 4), hepcidin, and TfR2 (exons 2, 4 and 6) genes in a cohort of 657 individuals with altered indicators of iron status.

Results: DHPLC identification of C282Y and H63D HFE alleles was in perfect agreement with the restriction endonuclease assay. Fourteen DNA samples were heterozygous for the HFE S65C mutation. In addition, we found novel mutations: two in HFE (R66C in exon 2 and R224G in exon 4), one in the hepcidin gene (G71D), and one in TfR2 (V22I), plus several intronic or silent substitutions. Six of the seven individuals with hepcidin or TfR2 coding mutations carried also HFE C282Y or S65C mutations.

Conclusion: DHPLC is an efficient method for mutational screening for the genes involved in hereditary hemochromatosis and for the study of their copresence.

Association analysis between anterior-pharynx defective-1 genes polymorphisms and Alzheimer's disease

Recent biological studies indicate the importance of anterior-pharynx defective-1 (APH-1) proteins in Alzheimer's disease (AD) pathogenesis. We scanned APH-1 genes for the presence of sequence variations by denaturing high performance liquid chromatography and analyzed their distribution in an Italian sample of 113 AD patients and 132 controls. We found six different polymorphisms: three of them, all in APH-1b, predict an aminoacid substitution (T27I, V199L and F217L); the others are either silent or in non-coding regions. None of them is significantly associated with the disease; data stratification by the apolipoprotein E epsilon4 carrier status show a trend for coexistence of the transversion c+651T>G (F217L) with the epsilon4 allele. Our data suggest that polymorphisms in APH-1a/b coding regions are not linked with higher risk for sporadic AD in our Italian population sample.

Chloride channel ClCN7 mutations are responsible for severe recessive, dominant, and intermediate osteopetrosis

Among 94 osteopetrotic patients presenting with a severe clinical picture and diagnosed early in life, 12 bore mutations in the ClCN7 gene, but only 7 of them had the expected two recessive mutations. The remaining five patients seem to be heterozygous for a ClCN7 mutation, and significant variations were observed in the clinical manifestations of their disease, even within the same family.

INTRODUCTION

Human osteopetroses are a heterogeneous group of diseases that include both infantile severe, autosomal recessive (ARO) and adult autosomal dominant (ADO) forms. Two genes, Atp6a3 (TCIRG1) and ClCN7, have been shown to be associated with human ARO, the latter of which is also thought to be responsible for ADO-II. However, patients with an intermediate phenotype have been described: the genetic basis of these observances is unknown.

MATERIALS AND METHODS

In this study, we report the clinical and molecular analysis of 94 patients in which a diagnosis of severe osteopetrosis was made within the first 2 years of age. Both TCIRG1 and CLCN7 genes were sequenced in all patients and the molecular findings were correlated to clinical parameters.

RESULTS AND CONCLUSIONS

In 56 of 94 patients with a classical picture of ARO, TCIRG1-dependent recessive mutations were found. In contrast, ClCN7 mutations were found in 12 cases (13%) of severe osteopetrosis, but only 7 of them had two recessive mutations identified: in 6 of these 7 cases, central nervous system manifestations were noted, and these patients had a poor prognosis. The remaining five cases were heterozygous for a ClCN7 mutation, including two brothers from a large family with a history of ADO-II in which the presence of a second ClCN7 mutation was formally excluded. Despite an early and severe clinical presentation, these five patients all reached adulthood, suggesting that the degree of dominant interference with chloride channel function can vary widely. Our findings suggest that recessive ClCN7-dependent ARO may be associated with CNS involvement and have a very poor prognosis, whereas heterozygous ClCN7 mutations cause a wide range of phenotypes even in the same family, ranging from early severe to nearly asymptomatic forms. These findings have prognostic implications, might complicate prenatal diagnosis of human osteopetroses, and could be relevant to the management of these patients.

Inhibition of energy metabolism down-regulates the Alzheimer related presenilin 2 gene

Defects in energy metabolism and oxidative stress play an important role in the pathogenesis of Alzheimer's Disease (AD). In sporadic AD cases, presenilin 2 (PS2) mRNA levels are decreased in brain areas affected by the disease. The aim of the present study was to investigate whether mitochondrial dysfunction might influence PS2 gene expression. We demonstrated that the inhibition of energy metabolism by sodium azide down-regulates PS2 gene expression through modification of promoter activity. No one of the analyzed transcription factors, sensitive to redox status of the cell, could explain this effect. Azide effect on PS2 expression was completely inhibited by the addition of an antioxidant suggesting that the imbalance of the cellular redox homeostasis modulates the expression of this gene.

Prolonged treatment with imatinib mesylate in patients with advanced chronic myeloid leukemia causes a reduction of bcr/abl mRNA levels independent of cytogenetic response

Bcr/abl mRNA levels were monitored in 13 patients with chronic myeloid leukemia receiving imatinib mesylate over a period of 78 weeks. During treatment median bcr/abl mRNA levels progressively declined from 77.2 normalized dose (nD) at baseline to 11.28 nD after 13 weeks ( P<0.05) and to 1.28 nD after 78 weeks ( P<0.05). After 13 weeks, bcr/abl mRNA levels were significantly lower in cytogenetic responders compared to nonresponders ( P<0.05), but subsequent decrease in the transcript levels caused the loss of any correlation to the cytogenetic status. These results suggest that bcr/abl mRNA levels may reflect cytogenetic response only during the early phases of imatinib therapy.

Low thymic output and reduced heterogeneity of alpha/beta, but not gamma/delta, T lymphocytes in infants with ataxia-telangiectasia

Ataxia-telangiectasia, a genetic disease caused by the homozygous mutation of the ATM gene, is frequently associated to a deficit of humoral and cellular immune functions. A decreased thymic output and skewed T cell and B cell receptor repertoires have been recently described in children over 7 years of age and in adults with this disease and have been proposed as a possible explanation for the immunodeficiency. To understand whether T cell defects arise early in life as a consequence of ATM gene mutations, we analysed the extent of thymic function by measuring the number of naïve T cells and by studying the heterogeneity of T cells by means of heteroduplex analysis, in two children less than 2 years old with a remarkable reduction of T cell count. We found that the thymic output is decreased in babies with ataxia-telangiectasia if compared with that observed in age-matched normal babies. The low production of new T cells is associated to a reduction of the diversity of alpha/beta, but not gamma/delta, T lymphocytes. Our data indicate that ATM mutation limits the generation of a wide alpha/beta T cell repertoire and this feature can be responsible for the immunodeficiency observed in ataxia-telangiectasia babies.

Essential Bacillus subtilis genes

To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

Impaired thymic output and restricted T-cell repertoire in two infants with immunodeficiency and early-onset generalized dermatitis

We evaluated the T-cell repertoire and the thymic output in two infants, one with Omenn Syndrome (OS) and another with complete DiGeorge Syndrome (DGS), who developed generalized dermatitis. The patients shared common T-cell abnormalities, as demonstrated by the low response to mitogenic stimulation, by an unusual usage of specific T-cell receptor (TCR) segments, and by a reduction of TCR diversity in both alpha/beta and gamma/delta populations. Furthermore, they both showed an impaired thymic function, as assessed by the low number of TCR recombination excision circles, which are formed from excised DNA during the rearrangement of TCR genes. These data indicated that generalized erythrodermia may be present in different forms of T-cell immunodeficiency and may reflect intrinsic defects in either V(D)J recombination or in thymic development, leading to the peripheral expansion of T-cell clonotypes, that bear peculiar TCR chains.

Inherited thrombophilic disorders in young adults with ischemic stroke and patent foramen ovale

BACKGROUND AND PURPOSE

The pathogenic link between patent foramen ovale (PFO) and stroke remains unknown in most cases. We investigated the association between inherited thrombophilic disorders and PFO-related strokes in a series of young adults in the setting of a case-control study.

METHODS

We investigated 125 consecutive subjects (age, 34.7+/-7.3 years) with ischemic stroke and 149 age- and sex-matched control subjects. PFO was assessed in all patients with transcranial Doppler sonography with intravenous injection of agitated saline according to a standardized protocol. Genetic analyses for the factor V (FV)(G1691A) mutation, the prothrombin (PT)(G20210A) variant, and the TT677 genotype of methylenetetrahydrofolate reductase (MTHFR) were performed in all subjects.

RESULTS

A pathogenic role of PFO was presumed in 36 patients (PFO+). Interatrial right-to-left shunt either was not detected or was considered unrelated to stroke occurrence in the remaining 89 patients (PFO-). The PT(G20210A) variant was more frequent in the PFO+ group compared with control subjects and the PFO- group (PFO+ versus control subjects, 11% versus 2%; 95% CI, 0.04 to 0.94; PFO+ versus PFO-, 11% versus 1.1%; 95% CI, 1.09 to 109; P=0.047). A similar distribution was observed for subjects carrying either the PT(G20210A) variant or the FV(G1691A) mutation (PFO+ versus control subjects, 19.4% versus 5.3%; 95% CI, 0.08 to 0.75; PFO+ versus PFO-, 19.4% versus 3.3%; 95% CI, 1.45 to 26.1; P=0.021). Combined thrombophilic defects were observed in 3 subjects of the PFO+ group, in 2 control subjects (8.3% versus 1.3%; 95% CI, 0.01 to 0.66; P=0.015), and in 0 subjects in the PFO- group. A trend toward a difference in the frequency of the FV(G1691A) mutation between PFO+ and control subjects was found after bivariate analysis (11% versus 3.3%; P=0.068) but not after multinomial logistic regression analysis. No significant association was found in the distribution of the TT MTHFR genotype in the 3 groups.

CONCLUSIONS

In young adults, the PT(G20210A) variant and, to a lesser extent, the FV(G1691A) mutation may represent risk factors for PFO-related cerebral infarcts. A role of systemic thrombophilic disorders in the pathogenesis of this specific subtype of stroke may be hypothesized.

Real-time quantitation of hepatitis B virus (HBV) DNA in tumorous and surrounding tissue from patients with hepatocellular carcinoma

Few data are available on the levels of HBV DNA in liver tissue of patients with hepatocellular carcinoma. In this study, HBV DNA was quantitated by a TaqMan real-time PCR method and results were normalised to an endogenous reference gene. The assay could detect reproducibly viral sequences from over 10(7) to less than 50 copies/microg of liver DNA. The HBV DNA content in liver samples from 11 HBsAg-positive patients (median: 10(5) copies/microg of DNA) was significantly higher (P < 0.001) compared to the viral DNA concentration detected in liver samples from 15 of 25 HBsAg-negative patients (median: 2.6 x 10(2) copies/microg). A liver DNA amount > or =1 HBV DNA copy per cell was detected in half of tissue samples from HBsAg-positive patients, and in none from HBsAg-negative ones. Liver tissue HBV DNA content was significantly higher in anti-HCV-negative than in anti-HCV-positive cases (P < 0.001). These results show that the quantitation of liver HBV DNA by real-time PCR can be useful to understand HBV state in hepatocellular carcinoma and viral interplay in patients with multiple viral infections.

Isomer-specific activity of dichlorodyphenyltrichloroethane with estrogen receptor in adult and suckling estrogen reporter mice

We investigated the tissue-specific effects of dichlorodyphenyltrichloroethane (DDT) isomers in adult and suckling newborn mice, using a novel mouse line engineered to express a reporter of estrogen receptor transcriptional activity (ERE-tkLUC mouse). The DDT isomers p,p'-DDT [1,1,1-trichloro2,2-bis(p-chlorophenyl) ethane] and o,p'-DDT [1,1,1-trichloro-2(p-chlorophenyl)-2-(o-chlorophenyl) ethane] were specifically selected as a weak and a strong estrogen, respectively. In adult male mice, p,p'-DDT induced luciferase activity in liver, brain, thymus, and prostate but not in heart and lung. The effect of p,p'-DDT was dose-dependent, maximal at 16 h after sc treatment, and completely blocked by the estrogen receptor antagonist ICI-182,780. In all the organs analyzed, except the liver, administration of o,p'-DDT showed a pattern of luciferase induction superimposable to that of its isomer p,p'-DDT. In liver, o,p'-DDT significantly decreased basal luciferase activity and blocked the reporter induction by 17beta-estradiol. These data lead us to hypothesize that a modulation of ER activity may be involved in the toxic effects of DDT demonstrated by epidemiological and experimental studies. Luciferase activity was also studied in 4-d-old mice lactating from a mother injected with either p,p'-DDT or o,p'-DDT. Both isomers induced a 2-fold increase in the newborn brain. An opposite effect was observed in liver, where p,p'-DDT increased and o,p'-DDT decreased luciferase, thus indicating that these compounds modulate ER activity in adult and newborn tissues by use of a similar mechanism. The ERE-tkLUC mouse proves to be a suitable tool to functionally assess the tissue specificity of estrogenic/antiestrogenic compounds in adult (as well as in suckling) mice.

Levels of beta-secretase BACE and alpha-secretase ADAM10 mRNAs in Alzheimer hippocampus

The amyloid cascade hypothesis suggests that amyloid precursor protein (APP) proteolytic processing is a key event in the pathogenesis of Alzheimer's disease (AD). The enzymes beta-site APP cleaving enzyme (BACE) and A disintegrin and metalloproteinase 10 (ADAM10) play an important role in APP proteolysis. We measured by real time quantitative polymerase chain reaction their mRNA levels in hippocampal and cerebellar sections from 13 AD and 12 control brains. BACE mRNA amounts were similar in patients and controls. In contrast, ADAM10 mRNA levels were twofold higher in AD samples, but without relationship to the severity of anatomical damage. The data do not support the hypothesis that alteration of BACE and ADAM10 expression are associated with development of late stages of AD.

Effects of erythropoietin and vitamin E-modified membrane on plasma oxidative stress markers and anemia of hemodialyzed patients

BACKGROUND

Oxidant stress has a pathogenic role in uremic anemia, possibly interfering with erythropoietin (EPO) function and red blood cell (RBC) survival. Therefore, it is expected that antioxidant therapy might exert a beneficial effect on these parameters.

METHODS

To test this hypothesis, we investigated some oxidant stress indices, anemia levels, and RBC survival in 47 hemodialysis (HD) patients randomly assigned to three groups. Patients in groups A (n = l8) and B (n = 20) were on dialysis therapy using conventional cellulosic and synthetic membranes and were administered high and low doses of recombinant human EPO (rHuEPO), respectively. Patients in group C (n = 9) were dialyzed with vitamin E-modified membranes (CL-Es) and investigated in a two-step prospective study. In step Cl, patients were administered rHuEPO doses similar to those of group A. In step C2, rHuEPO doses were reduced to those of group B. As oxidant stress markers, we determined in plasma the susceptibility of lipids to undergo iron-catalyzed oxidation (reactive oxygen molecules [ROMs] test) and malondialdehyde-4-hydroxynonenal (MDA-4HNE), alpha-tocopherol (alpha-T), total thiol (-SH), and total antioxidant activity. RBC survival was measured using the chromium 51 T/2 technique in 22 patients.

RESULTS

Results show that: (1) high rHuEPO doses (groups A and C1) were associated with decreased ROM production, low alpha-T levels, and slightly increased -SH levels compared with corresponding groups on low rHuEPO doses (groups B and C2); (2) treatment with CL-Es (group C) increased plasma alpha-T and decreased -SH levels; these data were associated with decreased indices of lipid peroxidation, particularly MDA-4HNE 1evels, only in patients administered low rHuEPO doses; (3) alpha-T concentration influenced RBC survival, which was remarkably decreased in HD patients; patients treated with CL-Es showed a better degree of anemia correction; and (4) alpha-T level correlated negatively with -SH level and seemed to be independent of the extent of peroxidation and oxidizability of plasma lipids.

CONCLUSION

Both EPO and CL-E can influence plasma antioxidants and, to an extent, lipid peroxidation processes. However, this study shows that even in patients treated with low rHuEPO doses, RBC survival close to normal and sufficient correction of anemia are achieved only when appropriate alpha-T levels are reached.

High prevalence of a variant of SENV in intravenous drug user HIV-infected patients

The prevalence, route of transmission, and clinical significance of SEN virus (SENV) infection was evaluated in 715 samples obtained from 150 blood donors, 165 patients infected by HIV, 150 with HCV/HBV infection, 80 with autoimmune diseases, 40 with Primary Immunodeficiency, 40 with sexually transmitted diseases, 40 polytransfused, and from 50 unselected patients. The identification of SENV-DNA was performed by polymerase chain reaction and hybridization, followed by an immunoenzymatic method that identify different SENV strains. SENV-A variant is largely represented among HIV-infected patients, being found in 71% of HIV(+) intravenous drug users and in 26% of individuals that had acquired HIV through sex. A high prevalence of SENV-A was observed also in HIV- polytransfused (27%) or in patients with sexually transmitted diseases (30%). These percentages are significantly higher than those observed in an unselected population and in blood donors. Prevalence of SENV-A is, therefore, high among HIV(+) patients with parental risk of exposure, but this infection does not appear to influence the clinical or immune status of HIV(+) patients.

Human mitochondrial ferritin expressed in HeLa cells incorporates iron and affects cellular iron metabolism

Mitochondrial ferritin (MtF) is a newly identified ferritin encoded by an intronless gene on chromosome 5q23.1. The mature recombinant MtF has a ferroxidase center and binds iron in vitro similarly to H-ferritin. To explore the structural and functional aspects of MtF, we expressed the following forms in HeLa cells: the MtF precursor (approximately 28 kDa), a mutant MtF precursor with a mutated ferroxidase center, a truncated MtF lacking the approximately 6-kDa mitochondrial leader sequence, and a chimeric H-ferritin with this leader sequence. The experiments show that all constructs with the leader sequence were processed into approximately 22-kDa subunits that assembled into multimeric shells electrophoretically distinct from the cytosolic ferritins. Mature MtF was found in the matrix of mitochondria, where it is a homopolymer. The wild type MtF and the mitochondrially targeted H-ferritin both incorporated the (55)Fe label in vivo. The mutant MtF with an inactivated ferroxidase center did not take up iron, nor did the truncated MtF expressed transiently in cytoplasm. Increased levels of MtF both in transient and in stable transfectants resulted in a greater retention of iron as MtF in mitochondria, a decrease in the levels of cytosolic ferritins, and up-regulation of transferrin receptor. Neither effect occurred with the mutant MtF with the inactivated ferroxidase center. Our results indicate that exogenous iron is as available to mitochondrial ferritin as it is to cytosolic ferritins and that the level of MtF expression may have profound consequences for cellular iron homeostasis.

Oxidative stress and cardiovascular disease in dialyzed patients

BACKGROUND/AIM

Oxidative damage has been suggested to play a key role in accelerated atherosclerosis and to be involved in cardiovascular disease (CVD) of dialyzed patients who are at risk of increased oxidative stress. The purpose of the present study was to examine the relationship between the severity of CVD and some markers of oxidative stress and antioxidant activity in our hemodialyzed (HD) and peritoneal dialysis (PD) patients.

METHODS

Plasma reactive oxygen metabolites, malondialdehyde and 4-hydroxynonenal (MDA-4HNE), thiols, alpha-tocopherol, and total antioxidant status (TAS) were measured in 55 HD and in 16 PD patients. CVD was considered as the result of variably combined cardiac, cerebral, and vascular pathologies which were scored and grouped in a single CVD index and analyzed with respect to the markers of the oxidative status. 16 normal subjects served as controls.

RESULTS

All patients showed evidence of increased oxidative stress which was more severe in HD than in PD patients and which was exacerbated by HD. When cardiac, cerebral, and vascular diseases were analyzed separately, plasma MDA-4HNE and TAS were significantly higher in more severely affected HD patients, but not in PD patients. In HD patients the CVD index was directly correlated with both MDA-4HNE and TAS (r = 0.42, p < 0.01; r = 0.39, p < 0.01) and inversely correlated with alpha-tocopherol (r = -0.32, p < 0.05). MDA-4HNE and TAS were directly correlated in HD patients and inversely correlated in control subjects.

CONCLUSIONS

Our data show that, in spite of increased antioxidant defense, there is a relationship between the degree of lipid peroxidation and the severity of CVD in HD patients. Moreover, these data underscore the utility of MDA-4HNE, alpha-tocopherol, and TAS in the evaluation of cardiovascular disease.