Determination of telomere length by flow-fluorescence in situ hybridization in Down's syndrome patients.

A new method for measuring telomere length in a population of Down's syndrome patients aged 18-60 years old is presented. The method is based on flow cytometry and quantitative fluorescence in situ hybridization (flow-FISH) on whole cells. At least three methods for measuring the length of telomere repeats have been described: (i) Southern blot analysis, and quantitative FISH using either (ii) digital fluorescence microscopy (Q-FISH) or (iii) flow cytometry (flow-FISH). Both Southern blot analysis and Q-FISH have specific limitations and are time-consuming, whereas flow-FISH needed relatively few cells (1.5-2.5 x 106) and could be completed in 24-48 h. The method can be used to rapidly determine telomere length in subsets of nucleated blood cells from patients with age-related diseases such as Down's syndrome, Alzheimer's disease and Werner syndrome.

High Th1-type cytokine serum levels in patients with infectious mononucleosis.

Most adults are asymptomatically infected with Epstein-Barr virus (EBV). Primary EBV infection is commonly associated with acute infectious mononucleosis (IM). T cell immune activation plays an important role in EBV-associated diseases. IM shows a mainly Th1-type profile, so Th1-type cytokines such as interleukin-2 (IL-2), interferon-gamma (IFN-gamma), and lymphotoxin (LT) are moderately enhanced. We measured IL-2 and IFN-gamma in serum during acute phase of the disease and during convalescence. Sera were collected from 23 IM patients, 13 patients with similar clinical manifestations but without IM, and 10 healthy donors. The levels of IL-2, IFN-gamma and IL-12 were significantly higher in patients with acute IM than in healthy individuals. IL-2, IFN-gamma and IL-12 decreased during convalescence. These three cytokines may be useful as sensitive markers of IM during severe illness and its later phases.

Relationship between clinical and genetic features in "inverted duplicated chromosome 15" patients.

Inverted duplicated chromosome 15 (Inv dup [15]) syndrome is a genetic disorder characterized by psychologic or intellectual language delay; neurologic signs, such as hypotonia, ataxia, and epilepsy; mental retardation ranging from mild to severe; and facial dysmorphisms. All patients present with a psychopathologic impairment that is highly variable in severity but always classifiable as pervasive developmental disorder (PDD). Many genetic mechanisms have been hypothesized to explain the clinical variability. This article describes the neurologic and psychopathologic features of six Inv dup(15) patients, one male and five females, between 8 and 14 years of age, all with a maternal marker chromosome. Four patients were diagnosed with PDD not otherwise specified, whereas two patients received a diagnosis of autism. Epilepsy was present in three patients (two generalized symptomatic and one focal symptomatic), and a correlation between the severity of the disease and its outcome was not always observed. Nevertheless, the influence of gene content of the marker chromosome, particularly the three gamma-aminobutyric acid-A receptor subunit genes, may represent the link between epilepsy, mental retardation, and PDD.

Pervasive developmental disorders and GABAergic system in patients with inverted duplicated chromosome 15.

Pervasive developmental disorders are characterized by severe, pervasive impairment in several areas of development, with distorted communication skills and stereotypical behavior. Pervasive developmental disorders have a heterogeneous etiology related to brain damage, familial affective psychopathology, chromosomal abnormalities, or dysfunction of neuromodulators. Recently, it has been suggested that the GABRB3 gene, located within chromosome 15q11-13, is a candidate for pervasive developmental disorder. In inverted duplicated chromosome 15 syndrome, in which there is a small marker chromosome derived from inversion and duplication of the chromosome 15q11-q13 region, all patients present with pervasive developmental disorder. To further investigate a possible involvement of the gamma-aminobutyric acid (GABA)ergic system in the inverted duplicated chromosome 15 syndrome, we evaluated plasma levels of GABA and diazepam binding inhibitor in 6 patients with inverted duplicated chromosome 15 and in 8 subjects not affected by neurologic disease. Our findings do not seem to support this hypothesis as no significant differences were found in the GABA and diazepam binding inhibitor plasma levels between patients with inverted duplicated chromosome 15 and controls, but we must consider the possibility that a genetic abnormality of the GABA(A) receptor could be present in patients with inverted duplicated chromosome 15 and still not be reflected in an alteration in either GABA or diazepam binding inhibitor levels in plasma.

Diazepam binding inhibitor (DBI) in the plasma of pediatric and adult epileptic patients.

The polypeptide diazepam binding inhibitor (DBI) displays epileptogenic activity by binding to benzodiazepine receptors. We analyzed DBI concentrations in the plasma of pediatric and adult epileptic patients, as a possible peripheral marker in epilepsy. DBI plasma concentrations are significantly higher (+ 62%, P < 0.001) in adult patients and slightly but significantly higher (+15%, P < 0.01) in pediatric patients, compared to age-related controls. Strikingly, plasma DBI is much higher (+81%, P < 0.001) in generalized epilepsy in adults and in drug-resistant pediatric and adult patients. Based on these findings, plasma DBI may be considered as a peripheral biological marker of epilepsy and, in association with lymphocyte benzodiazepine receptor density, of anticonvulsant drug responsiveness.

Decreased density of lymphocyte benzodiazepine receptors in drug-resistant epileptic patients.

Peripheral benzodiazepine receptors (PBR) may have a role in epilepsy and in mediating antiepileptic drug effects. Since PBR in blood mononuclear cells may be acted on by anticonvulsant drugs, we investigated possible modifications of these receptors in newly diagnosed patients, before and after antiepileptic treatment and in drug-resistant epileptic patients. A significantly lower receptor density, with no difference in affinity, was observed in drug-resistant patients, compared to newly diagnosed patients and to normal age-related controls. We suggest the possible use of PBR as a peripheral marker of drug response.