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Biomedical subjects

A Federico

Publications and source records attributed to A Federico.

At least 91 records · Page 5Linked to original sources
PubMed2000

MECP2 mutation in male patients with non-specific X-linked mental retardation.

In contrast to the preponderance of affected males in families with X-linked mental retardation, Rett syndrome (RTT) is a neurological disorder occurring almost exclusively in females. The near complete absence of affected males in RTT families has been explained by the lethal effect of an X-linked gene mutation in hemizygous affected males. We report here on a novel mutation (A140V) in the MECP2 gene detected in one female with mild mental retardation. In a family study, the A140V mutation was found to segregate in the affected daughter and in four adult sons with severe mental retardation. These results indicate that MECP2 mutations are not necessarily lethal in males and that they can be causative of non-specific X-linked mental retardation.

Adult↗
PubMed2000

Apoptotic response and cell cycle transition in ataxia telangiectasia cells exposed to oxidative stress.

The recently identified ATM gene plays a role in a signal transduction network activating multiple cellular functions in response to DNA damage. An attractive hypothesis is that the ATM protein is involved in a specialized antioxidant system responsible for detoxifying reactive oxygen intermediate and that the absence or dysfunction of this protein in AT cells would render them less capable of dealing with oxidative stress. In order to investigate the role of the ATM gene in cell cycle control and programmed cell death, Lymphoblastoid cell lines derived from four Ataxia-Telangiectasia (AT) patients and six controls have been analyzed. All cell lines were incubated with 2-deoxy-D-ribose (dRib), a reducing sugar that induces apoptosis through oxidative stress. The result showed an impaired response to dRib-induced apoptosis in AT cells, as well as a defect of cellular cycle arrest in G1/S phase and a normal expression of p53 protein. This indicate that the kinase activity of ATM gene product plays a very important role in the cellular response to oxidative stress. In conclusion the altered response of AT cells to oxidative stress and particularly their resistance to apoptotic cell death, could explain the high predisposition of these cells to progress toward malignant transformation.

Adolescent↗
PubMed2000

Vitamin E serum levels and gastric cancer: results from a cohort of patients in Tuscany, Italy.

Alpha-tocopherol has been reported to play an important role against oxidative damage and in the inhibition of cell transforming and mutagenesis. We analysed vitamin E serum levels in 51 cases of patients affected by gastric cancer at different stages of the disease, and in 49 age-matched controls. All patients had normal values of alpha-tocopherol. However, when patients have been grouped according to histotype of gastric lesions, a significant vitamin E increase has been found in diffuse gastric cancer histotype compared to the intestinal histotype. Our results suggest that a correlation between vitamin E serum levels and gastric cancer histotype should be considered.

Aged↗
PubMed2000

Accuracy of clinical diagnostic criteria for Friedreich's ataxia.

The accuracy of the diagnostic criteria for Friedreich's ataxia proposed by Harding and by the Quebec Cooperative Study on Friedreich's Ataxia was studied in 142 patients with progressive unremitting ataxia of autosomal recessive inheritance or sporadic occurrence. Eighty-eight patients received the molecular diagnosis of Friedreich's ataxia. Traditional diagnostic criteria are characterized by high specificity, but they yield a high number of false-negative diagnoses. We suggest three levels of diagnostic certainty: (1) possible Friedreich's ataxia, defined as sporadic or recessive progressive ataxia with (a) lower limb areflexia and dysarthria, Babinski sign, or electrocardiographic repolarization abnormalities, or (b) with lower limb retained reflexes and electrocardiographic repolarization abnormalities (95% sensitivity and 88% positive predictive value); (2) probable Friedreich's ataxia as defined by Harding's criteria (63% sensitivity and 96% positive predictive value) or by Quebec Cooperative Study on Friedreich's Ataxia criteria (63% sensitivity and 98% positive predictive value); (3) definite diagnosis, molecularly confirmed.

Adolescent↗
PubMed2000

Imaging axonal damage in multiple sclerosis by means of MR spectroscopy.

Axonal damage in multiple sclerosis has become an important issue. This has been emphasized by recent in vivo proton magnetic resonance (MR) spectroscopy and in vitro pathology studies that have found axonal damage in both lesions and the surrounding normal-appearing white matter. In particular, proton MR spectroscopy, by monitoring levels of N-acetylaspartate (a putative marker of axonal integrity), has been particularly illuminating, as the extent of axonal injury associated with white matter inflammation and demyelination had not been well appreciated from classical pathology studies. Recent MR data demonstrate that cerebral axonal damage begins and contributes to disability from the earliest stages of the disease. This implies that the apparently primary role of axonal damage and loss in the pathogenesis of the disease should be given due importance, and argues for the early treatment of multiple sclerosis with agents directed not only against inflammation, but also towards axonal protection.

Animals↗
PubMed2000

Enhanced 2-deoxy-D-ribose-induced-apoptosis, a phenotype of lymphocytes from old donors, is not observed in the Werner syndrome.

Werner syndrome (WS) is an inherited disease characterized by the premature appearance of features of normal aging in young adults. To evaluate the relationship between Werner syndrome and aging, we analyzed the apoptotic response of peripheral blood lymphocytes (PBLs) from two WS patients (mean age 34 years old) incubated with 2-deoxy-D-ribose (dRib), a reducing sugar that induces apoptosis in quiescent cells through an oxidative stress; the results have been compared to two control groups (mean age 35 and 83 years old, respectively). The presence of apoptotic cells was detected by light microscopy, flow cytometry, and agarose gel electrophoresis. In all three groups an increased time-dependent apoptotic response was evident, but the apoptotic response to dRib was lower in WS's cells than in cells from age-matched controls and less than in cells from older subjects. Our results confirm a low susceptibility of WS cells to DNA damaging agents as dRib and suggest that the pathogenic mechanisms underlying normal cellular aging and WS's cellular senescence may be different.

Adult↗
PubMed2000

Can dietary intake influence plasma levels of amino acids in liver cirrhosis?

BACKGROUND: Modifications in plasma amino acid patterns in cirrhotics are attributed to impaired liver function, being more evident in alcoholic than in viral cirrhosis. AIM: To evaluate whether diet influences plasma amino acid concentrations in different aetiological groups of cirrhotics. PATIENTS: Study population comprised 40 patients with cirrhosis (25 virus- and 15 alcohol-related], all Child A, and 30 healthy subjects (controls). METHOD: A food frequency and quality questionnaire was utilized to determine dietary history and alcohol intake. Nutritional status was evaluated by anthropometric method. Amino acids were determined, on venous blood samples, using a specific analyzer while cysteine was evaluated by fluorescent high power liquid chromatography RESULTS: The total daily intake of calories, proteins, lipids, and carbohydrates was similar in all individuals. Food quality distinguished the cirrhotics from the controls, but not the different aetiological groups of cirrhotics. Plasma cysteine levels were significantly lower, while aromatic amino acids and methionine were significantly higher, in all cirrhotics (p<0.001 and p<0.01, respectively, versus controls). The decrease in cysteine and the increase in other amino acids were more marked in alcoholics (p<0.01). CONCLUSIONS: Ethanol intake, but not diet, further enhances the changes in plasma aromatic amino acids, methionine and cysteine induced by impaired liver function in patients with cirrhosis, suggesting a direct interference of alcohol in their metabolism.

Adult↗
PubMed2000

Oral self-mutilation in a patient with rhombencephalosynapsys.

Rhombencephalosynapsis (RS) is a rare cerebellar malformation. Its essential features are the absence of the incisura cerebelli posterior, fusion of the cerebellar hemispheres, the absence of the velum medullare anterius and nuclei fastigii, and fusion of the dentate nuclei, which are shifted towards the mid-line. Clinically, affected patients present with signs of cerebellar and motor disturbances. The present report describes a new patient affected by RS. The subject first presented at the age of 22 years because of a psychiatric symptomatology which was characterized by obsessive oral self-mutilation associated with an intellectual disability. Objective evaluation documented dysmorphic features, while neurological examination showed only a slight truncal ataxia. The subject's IQ was 74 on the Wechsler Scale (verbal IQ = 79, performance IQ = 74). Psychiatric evaluation with DSM-IV criteria documented an obsessive-compulsive personality disorder associated with emotional instability and oral self-mutilation. The typical picture of rhombencephalosynapsis was evident on magnetic resonance imaging. Both chromosomal analysis and routine biochemical investigations were normal. The relationship between oral self-injurious behaviour and cerebellar malformations is discussed with particular regard to the behavioural aspects of cerebellar congenital pathology in affective disorders and in autism.

Adult↗
PubMed2000

Short synthetic peptides derived from viral proteins compete with HIV gp120 for the binding to CD4 receptors.

In the complex mechanism of adhesion, internalization, and infection of cells by human immunodeficiency virus (HIV) viral particles, a determinant role is played by the viral envelope glycoprotein gp120, which binds to CD4 receptors of T cells and monocytes. We tested the ability of a panel of 7- to 12-residue synthetic peptides, selected from the region 414-434 of the HIV-1 gp120, to inhibit the binding of the viral protein to CD4 receptors of cultured human lymphoid cells. The assay was based on the observation that the binding of gp120 to the receptors interferes with the binding of a specific anti-CD4 monoclonal antibody, as a result of the masking of the antibody epitope; thus, we tested whether preincubation of cells with the peptides before gp120 addition might restore the recognition of the CD4 molecule by the antibody. High expression of CD4 receptors was thus assumed as indication that the binding of the viral protein had been inhibited. Maximum activity was displayed by a 9-residue peptide located near the amino terminal end of the 414-434 fragment. In addition, several fragments deduced from other viral proteins, possessing partial amino acid sequence homology with the HIV gp120 fragment, exhibited a similar type of interaction with the CD4 receptor. All active peptides contain the Cys residue (position 423 of gp120). This residue is essential, although not sufficient, for inhibiting gp120 binding, as few other amino acid residues within the fragment play a complementary role in increasing or decreasing the inhibitory ability.

Amino Acid Sequence↗
PubMed2000

Proton MR spectroscopy to assess axonal damage in multiple sclerosis and other white matter disorders.

Proton MR spectroscopy allows in vivo measurement of N-acetylaspartate in white matter, providing a biochemical index of axonal integrity. Several recent studies of patients with multiple sclerosis and other white matter disorders have shown both transient and sustained decreases in N-acetylaspartate in white matter lesions and in brain regions appearing normal on conventional MRI. These data have emphasised that a substantial amount of axonal damage or loss (presumably secondary to myelin pathology) is consistently present in most of these disorders. Recent post-mortem studies support these results. In contrast to changes seen with conventional MR imaging, decreases in N-acetylaspartate have shown a close correlation with changes in neurological status. This suggests that axonal damage may be more relevant than demyelination for determining chronic functional impairments in primary white matter diseases. Thus, serial measurement of brain N-acetylaspartate with proton MR spectroscopy can provide a reliable and clinically-relevant monitor of disease evolution. As pathological changes responsible for long-term morbidity are logically important targets for therapeutic agents, early treatment directed at axonal protection should be useful in these disorders.

Axons↗
PubMed1999

Association of trisomy 9p and band heterotopia.

Patients with the trisomy 9p syndrome and CNS abnormalities have been poorly assessed. We report a patient with trisomy 9p who showed band heterotopia on MRI. Abnormal neuronal migration is sufficiently frequent in patients with the trisomy 9p syndrome that brain MRI should be routinely considered in all patients with this syndrome.

Adult↗
PubMed1999

Detection of a rare Wilson disease mutation associated with arylsulfatase A pseudodeficiency.

We have studied a patient with Wilson disease (WD), belonging to a family segregating late-onset, dominant cerebellar ataxia. Analysis of the WD gene showed that the patient is a compound heterozygote, carrying the 14His1069Gln mutation from the father and the 8Gly710Ser mutation from the mother. The 8Gly710Ser is a mutation described previously only in a Swedish patient. Our patient is also homozygous for arylsulfatase A pseudodeficiency. This genetic defect, which has been reported in association with other neuropsychiatric syndromes, has not been described in WD.

Adult↗