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B-cell chronic lymphocytic leukemia (CLL) follows a heterogeneous clinical course, for which several biological markers may predict clinical outcome. Cytogenetic aberrations are considered major prognostic indicators for predicting the survival of CLL patients. Given the difficulties in obtaining abnormal metaphases in CLL, fluorescent in situ hybridization (FISH) with specific probes is generally used to detect the most frequent abnormalities. To determine the best strategy for identifying cytogenetic abnormalities, we compared results obtained by FISH analysis on peripheral blood mononuclear cells with those obtained by FISH after culture with mitogens. We studied 46 CLL patients selected from two different institutions. The most frequent structural aberrations leading to loss of genetic material were loss of the 13q14 region, in 32 cases (70%), and loss of TP53 in 11 cases (24%). Of the 46 cases patients, 10 patients (21.7%) had deletion of the ATM locus at 11q22 and 8 patients (17%) had trisomy 12. Results could be interpreted as discordant in four cases in which the abnormal clone was small and both values were around the threshold. FISH performed on stimulated cells detected the same frequency of abnormalities as FISH performed without culture. This equivalence between the two techniques allows performing both conventional cytogenetic and FISH analyses on the same sample.

Objectives: The aim of the study is to assess the effect of ring wearing and ring types on hand contamination and efficacy of alcohol-based hand disinfection among nurses working in intensive care settings., Methods: Hand cultures were obtained from 84 nurses providing direct patient care in intensive care units of a pediatric hospital. Colony counts were compared depending on ring wearing and the type of ring worn. Twenty-eight nurses were asked to a wear plain wedding ring, 28 to wear rings with stones and 28 not to wear any rings, starting 15 days before and continuing throughout the study. Cultures were obtained by using sterile gloves containing phosphate-buffered-saline solution (PBS) after an alcohol-based hand disinfectant was used and bacteria were identified with standard laboratory tests., Results: The nurses wearing rings had more Gram-positive, Gram-negative and total bacterial colonization on their hands than the nurses without rings despite using an alcohol-based rub (p=0.001). When comparing the two groups with rings (plain wedding rings and rings with stones), colony counts of Gram-positive, Gram-negative and total bacteria did not differ (p>0.05)., Conclusions: Ring wearing increases the bacterial colonization of hands and alcohol-based hand disinfection might not significantly reduce contamination of the ring-wearing hands. The type of ring did not cause any significant difference on the bacterial load. Wearing rings could increase the frequency of transmission of potential nosocomial pathogens.

Three clusters of Chryseobacterium meningosepticum infections in a tertiary health center in July 2006 and January 2007 involving 8 newborns and 5 older children were investigated. The index patient was from the neonatal intensive care unit, and the older patients were from other pediatric wards. Cultures were obtained from the environment and from health care workers' hands as part of an outbreak investigation. C meningosepticum was isolated from hand cultures obtained from a senior resident and from environmental cultures obtained from powdered infant formula, an electrical button, a computer keyboard, phone, a doorknob, and an Ambu bag. Antibiogram typing and enterobacterial repetitive intergenic consensus sequence polymerase chain reaction indicated that all of the isolates were epidemiologically related. Nine patients improved on antimicrobial treatment, and 4 premature infants died after the infection. C meningosepticum is a well-known etiologic agent for nosocomial infections involving newborns and immunocompromised patients. Wet and dry environmental surfaces and equipment may act as a source or play a role in disseminating the microorganism. Outbreaks may be controlled with strong emphasis on infection control measures.

Subtle variation in the expression or function of a small group of transcription factors can drive leukemogenesis. The CEBPA protein is known to regulate the balance between cell proliferation and differentiation during early hematopoietic development and myeloid differentiation. In human myeloid leukemia, CEBPA is frequently inactivated by mutation and indirect and posttranslational mechanisms, in keeping with tumor suppressor properties. We report that CEBPA is activated by juxtaposition to the immunoglobulin gene enhancer upon its rearrangement with the immunoglobulin heavy-chain locus in precursor B-cell acute lymphoblastic leukemia harboring t(14;19)(q32;q13). Overexpression of apparently normal CEBPA RNA or protein was observed in 6 patients. These data indicate that CEBPA may exhibit oncogenic as well as tumor suppressor properties in human leukemogenesis.

Chromosome 21 is frequently rearranged in hematopoietic malignancies. In order to detect new chromosomal aberrations, the Groupe Français de Cytogénétique Hématologique collected a series of 107 patients with various hematologic disorders and acquired structural abnormalities of the long arm of chromosome 21. The abnormalities were subclassified into 10 groups, according to the location of the 21q breakpoint and the type of abnormality. Band 21q22 was implicated in 72 patients (excluding duplications, triplications, and amplifications). The involvement of the RUNX1 gene was confirmed in 10 novel translocations, but the gene partners were not identified. Eleven novel translocations rearranging band 21q22 with bands 1q25, 2p21, 2q37, 3p21, 3p23, 4q31, 6p24 approximately p25, 6p12, 7p15, 16p11, and 18q21 were detected. Rearrangements of band 21q11 and 21q21 were detected in six novel translocations with 5p15, 6p21, 15q21, 16p13, and 20q11 and with 1p33, 3q27, 5p14, 11q11, and 14q11, respectively. Duplications, triplications, amplifications, and isodicentric chromosomes were detected in eight, three, eight, and three patients, respectively. The present study shows both the wide distribution of the breakpoints on the long arm of chromosome 21 in hematopoietic malignancy and the diversity of the chromosomal rearrangements and the hematologic disorders involved. The findings invite further investigation of the 21q abnormalities to detect their associated molecular rearrangements.

The TAL1 locus on chromosome band 1p32 is rearranged in 15 to 29% of human T-cell acute lymphoblastic leukemias (T-ALLs). These alterations consist of either a tald submicroscopic deletion (12-26% of T-ALL) or a t(1;14)(p32;q11) chromosomal translocation (3% of childhood T-ALL). Both types of alterations preferentially affect the 5' part of the TAL1 locus. Their main consequence appears to be transcriptional activation of the TAL1 gene. We have characterized two cases of t(1;14)(p32;q11) in ALL. Both affect the TCR delta gene segments at 14q11 and the 5' part of the TAL1 locus at 1p32. The first case represented a 'classical' t(1;14), associated with T-ALL. Its analysis indicates the use of a recombination signal-like sequence localized in the third exon of TAL1 in the translocation process. In the other case, the rearrangement to the D delta region occurred 5' to the TAL1 transcription start sites. This case exhibited a B-lymphoid immunophenotype thus suggesting that the putative oncogenicity of TAL1 activation is not restricted to T-cell malignancies.