Biomedical subjects

Alberto Albertini

Publications and source records attributed to Alberto Albertini.

32 records · Page 2Linked to original sources

PubMed2003

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.

Adult↗

PubMed2003

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

UNLABELLED: 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.

Adolescent↗

PubMed2003

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.

Antimicrobial Cationic Peptides↗

PubMed2003

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.

Antiretroviral Therapy, Highly Active↗

PubMed2002

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.

Aged↗

PubMed2002

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.

Blotting, Western↗

PubMed2002

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.

Adult↗

PubMed2002

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.

Aged↗

PubMed2002

Transmission of SEN virus from mothers to their babies.

Sera from 30 women at high risk for infection, one half of which were SEN virus positive (SENV(+)), were collected at delivery to study SENV mother-to child transmission. Thirteen of their babies were positive for at least one SENV strain: one baby was SENV(+) at birth, eight became positive within 6 months from delivery, and four became positive in the following months. Our data indicate that vertical transmission of SENV does occur, presumably, at delivery, but it may not induce persistent viremia. This is supported by the fact that, generally, SENV is not detected at birth, by the high SENV homology in the sequences found in the mothers and in their children, by a lack of other risk factors for infection of the babies, and by the irregular detection of SENV in the follow-up. No clinical events surely linked to SENV infection were found, but transient elevations of alanine aminotransferase were observed in babies followed for a long period of time.

DNA Virus Infections↗

PubMed2002

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.

Adult↗

PubMed2002

Thalamic infarcts in young adults: relationship between clinical-topographic features and pathogenesis.

BACKGROUND: Most reports on thalamic infarcts have focused on clinicoanatomical correlations while the mechanisms of stroke have rarely been investigated. Moreover, most series have included mainly elderly stroke patients, whereas scarce information is available about the etiology of thalamic infarcts in the young. OBJECTIVE: To investigate the mechanisms of thalamic infarcts according to vascular territory in a series of young adults. METHODS: A sample of 24 consecutive patients with thalamic infarcts were found in an unselected series of 129 patients with cerebral infarction aged 18-45 years. Diagnostic investigation included computed tomography and magnetic resonance imaging scans, ultrasonic scanning of the extracranial and intracranial arteries, conventional angiography and magnetic resonance angiography, transthoracic and transesophageal echocardiography and extensive thrombophilic studies. The affected vascular territory within the thalamus was determined using standard templates. RESULTS: Thalamic infarcts constituted almost one fifth of the ischemic strokes in our series. Ten patients (42%) had infarct in the territory of the thalamogeniculate pedicle (group 1), 10 (42%) in the territory of the paramedian thalamosubthalamic artery (group 2) and 3 (12%) in the territory of the tuberothalamic artery (group 3). In 1 patient (4%), the lesion involved more than one vascular thalamic territory. A significant association between cardioembolism and paramedian infarcts was found when comparing the mechanisms of stroke of group 2 with those of the group including infarcts in other thalamic territories (p = 0.002) and with those of group 1 (p = 0.02). CONCLUSIONS: Our findings provide information about the epidemiology of thalamic infarcts in young adults and point to a differential association between the distribution of infarcts in specific vascular territories and the mechanism of stroke.

Adult↗

PubMed2002

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.

Aldehydes↗

PubMed2002

Plasma homocysteine concentration, C677T MTHFR genotype, and 844ins68bp CBS genotype in young adults with spontaneous cervical artery dissection and atherothrombotic stroke.

BACKGROUND AND PURPOSE: The role of mild hyperhomocysteinemia as a risk factor for cerebral ischemia may depend on stroke subtype. To test this hypothesis, we undertook a prospective case-control study of a group of patients with spontaneous cervical artery dissection (sCAD), a group of patients with atherothrombotic stroke (non-CAD), and a group of control subjects. METHODS: Fasting total plasma homocysteine (tHcy) concentration, C677T MTHFR genotype, and 844ins68bp CBS genotype were determined in 25 patients with sCAD, 31 patients <45 years of age with non-CAD ischemic stroke, and 36 control subjects. Biochemical data in the patient groups were obtained within the first 72 hours of stroke onset. RESULTS: Median tHcy levels were significantly higher in patients with sCAD (13.2 micromol/L; range, 7 to 32.8 micromol/L) compared with control subjects (8.9 micromol/L; range, 5 to 17.3 micromol/L; 95% CI, 1.05 to 1.52; P=0.006). Cases with tHcy concentration above the cutoff level of 12 micromol/L were significantly more represented in the group of patients with sCAD compared with control subjects (64% versus 13.9%; 95% CI, 2.25 to 44.23; P=0.003); a significant association between the MTHFR TT genotype and sCAD was also observed (36% versus 11.1%; 95% CI, 1.10 to 19.23; P=0.045). No significant difference in tHcy levels and in the prevalence of thermolabile MTHFR was found between patients with non-CAD ischemic stroke and control subjects and between patients with sCAD and non-CAD ischemic stroke. The distribution of the 844ins68bp CBS genotype and the prevalence of subjects carrying both the TT MTHFR and 844ins68bp CBS genotypes were not significantly different among the 3 groups. CONCLUSIONS: Our results are consistent with the hypothesis that increased plasma homocysteine levels and the TT MTHFR genotype may represent risk factors for sCAD. In contrast, their role in atherothrombotic strokes remains a contentious issue.

Adult↗

PubMed2002

Plasma total antioxidant capacity in hemodialyzed patients and its relationships to other biomarkers of oxidative stress and lipid peroxidation.

Patients undergoing long-term hemodialysis (HD) exhibit increased levels of oxidative stress, likely contributing to the increased rate of cardiovascular disease. The present study represents a critical evaluation of some of the most widely used oxidative indicators, as applied to the monitoring of hemodialysis-associated oxidative stress. Total plasma antioxidant capacity was determined by two independent procedures, the total antioxidant status (TAS) and the ferric reducing ability of plasma (FRAP) methods. Plasma lipid peroxidation was assessed by determining the peroxidation products malonaldehyde and 4-hydroxynonenal (MDA-4HNE) as well as lipid hydroperoxides ("Fox-2" and "d-ROMs" methods). Total plasma thiols and plasma alpha-tocopherol were also determined. MDA-4HNE levels were higher in HD patients and decreased following HD, possibly due to passive diffusion across dialysis filters. d-ROMs were also higher in HD patients but exhibited a further increase following the dialysis procedure. Serum alpha-tocopherol did not show any significant differences. Plasma thiols were lower in HD patients and were restored following HD. Plasma total antioxidant capacity determined with either method was unexpectedly higher in HD patients compared to controls, and decreased following HD. These data indicate that, of the biomarkers studied, d-ROMs level is the one more accurately reflecting the oxidative alterations taking place in HD patients, while determination of MDA-4HNE fails to detect oxidation occurring during the HD sessions. In addition, our findings point out that the determination of total antioxidant capacity in HD patients is severely affected by the concomitant fluctuations in plasma urate levels and therefore needs careful interpretation.

Adult↗