H2A.Z-dependent crosstalk between enhancer and promoter regulates cyclin D1 expression

H2A.Z association with specific genomic loci is thought to contribute to a chromatin structure that promotes transcription activation. Acetylation of H2A.Z at promoters of oncogenes has been linked to tumorigenesis. The mechanism is unknown. Here, we show that in triple negative breast cancer cells, H2A.Z bound to the promoter of the constitutively, weakly expressed cyclin D1 oncogene (CCND1), a key regulator of cellular proliferation. Depleting the pool of H2A.Z stimulated transcription of CCND1 in the absence of its cognate transcription factor, the estrogen receptor (ER). During activation of CCND1, H2A.Z was released from the transcription start site (TSS) and downstream enhancer (enh2) sequences. Concurrently, acetylation of H2A.Z, H3 and H4 at the TSS was increased but only H2A.Z was acetylated at enh2. Acetylation of H2A.Z required the Tip60 acetyltransferase to be associated with the activated CCND1 on both TSS and enh2 sites. Depletion of Tip60 prevented CCND1 activation. Chromosome conformation capture experiments (3C) revealed specific contacts between the TSS and enh2 chromatin regions. These results suggest that release of a histone H2A.Z-mediated repression loop activates CCND1 for transcription. Our findings open new avenues for controlling and understanding aberrant gene expression associated with tumorigenesis.

MicroScope: a platform for microbial genome annotation and comparative genomics

The initial outcome of genome sequencing is the creation of long text strings written in a four letter alphabet. The role of in silico sequence analysis is to assist biologists in the act of associating biological knowledge with these sequences, allowing investigators to make inferences and predictions that can be tested experimentally. A wide variety of software is available to the scientific community, and can be used to identify genomic objects, before predicting their biological functions. However, only a limited number of biologically interesting features can be revealed from an isolated sequence. Comparative genomics tools, on the other hand, by bringing together the information contained in numerous genomes simultaneously, allow annotators to make inferences based on the idea that evolution and natural selection are central to the definition of all biological processes. We have developed the MicroScope platform in order to offer a web-based framework for the systematic and efficient revision of microbial genome annotation and comparative analysis (http://www.genoscope.cns.fr/agc/microscope). Starting with the description of the flow chart of the annotation processes implemented in the MicroScope pipeline, and the development of traditional and novel microbial annotation and comparative analysis tools, this article emphasizes the essential role of expert annotation as a complement of automatic annotation. Several examples illustrate the use of implemented tools for the review and curation of annotations of both new and publicly available microbial genomes within MicroScope's rich integrated genome framework. The platform is used as a viewer in order to browse updated annotation information of available microbial genomes (more than 440 organisms to date), and in the context of new annotation projects (117 bacterial genomes). The human expertise gathered in the MicroScope database (about 280,000 independent annotations) contributes to improve the quality of microbial genome annotation, especially for genomes initially analyzed by automatic procedures alone.Database URLs: http://www.genoscope.cns.fr/agc/mage and http://www.genoscope.cns.fr/agc/microcyc.

[Children born with a cleft: treatment at the CHUV in Lausanne]

A cleft can be labial, labial-maxillary, unilateral or bilateral labial-maxillary-palatal, or isolated palatal. A multidisciplinary team includes several specialists who will handle the diverse problems of children born with a cleft. This team will follow the child through each developmental stage and assemble an optimal treatment plan, thus reducing the onus on the family. Depending on the type of cleft and the age of the child, feeding, speech, ORL, dental, orthodontic, esthetic and possibly also psychological problems will be taken care of. This is why cleft treatment starts at the time it is diagnosed, before or after birth, and ends when the child is fully grown. It requires a complete interdisciplinary team and the collaboration with obstetricians and geneticians.

Eliminating epigenetic barriers induces transient hormone-regulated gene expression in estrogen receptor negative breast cancer cells

In breast cancer, approximately one-third of tumors express neither the estrogen receptor (ERalpha) nor estrogen-regulated genes such as the progesterone receptor gene (PR). Our study provides new insights into the mechanism allowing hormone-activated expression of ERalpha target genes silenced in ERalpha-negative mammary tumor cells. In cell lines derived from ERalpha-negative MDA-MB231 cells, stable expression of different levels of ERalpha from a transgene did not result in transcription of PR. A quantitative comparative analysis demonstrates that inhibiting DNA methyltransferases using 5-aza-2'-deoxycytidine or specific disruption of DNMT1 by small interfering RNAs and treatment with the histone-deacetylase inhibitor trichostatin A enabled ERalpha-mediated hormone-dependent expression of endogenous PR. We show that demethylation of a CpG island located in the first exon of PR was a prerequisite for ERalpha binding to these regulatory sequences. Although not a general requirement, DNA demethylation is also necessary for derepression of a subset of ERalpha target genes involved in tumorigenesis. PR transcription did not subsist 4 days after removal of the DNA methyltransferase blocking agents, suggesting that hormone-induced expression of ERalpha target genes in ERalpha-negative tumor cells is transient. Our observations support a model where an epigenetic mark confers stable silencing by precluding ERalpha access to promoters.

Epidemiology of invasive aspergillosis in France: a six-year multicentric survey in the Greater Paris area

Invasive aspergillosis is the most prevalent mould infection. An epidemiological surveillance network was set up in 18 teaching hospitals in Paris and the Greater Paris area. Prospective surveillance was conducted between 1994 and 1999. Between 1994 and 1997 cases were categorized as proven or probable aspergillosis and then the European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria were used. The authors analysed 621 cases (115 proven, 506 probable). No seasonal variation was found. Haematological disorders (73%) including stem-cell transplantation (36%), solid-organ transplantations (10%) and AIDS (9%) were the main underlying conditions. The crude mortality was 63%. Incidence of IA was 8% (CI(95): 6.5-9.5) in acute myelocytic leukaemia and 6.3% (CI(95): 4.3-8.3) in acute lymphocytic leukaemia. Incidence was 12.8% (CI(95): 10.8-14.8) following allogeneic stem-cell transplantation and 1.1% (CI(95): 0.7-1.5) following autologous stem-cell transplantation. In solid-organ recipients incidence ranged from 11% following heart-lung transplantation and small bowel to 0.4% following kidney transplantation. Incidence in HIV infected patients ranged from 0.02 to 0.13% per annum. This large series confirmed that patients with haematologic disorders and transplantations are the most at risk for IA.

[Development of a predictive model for respiratory isolation of patients suspected of having pulmonary tuberculosis]

INTRODUCTION

As numerous nosocomial outbreaks of pulmonary tuberculosis have been reported during the last two decades, prompt identification and effective isolation of contagious patients should be made a priority in tuberculosis control policies. There is a need to develop a predictive model which would allow prompt recognition and isolation of smear-positive patients.

CURRENT KNOWLEDGE AND KEY POINTS

Various authors have attempted to improve the respiratory isolation policies for patients suspected of having pulmonary tuberculosis. A French multicenter prospective study of 211 patients suspected of having pulmonary tuberculosis established that: 1) the current respiratory isolation policy of suspected pulmonary tuberculosis needs improvement (sensitivity = 71.4%; i.e., 28.6% of smear-positive patients are admitted without isolation) and 2) better interpretation of clinical and radiological data available on patient admission could improve the adequacy of respiratory isolation. Univariate analysis showed that predictive factors of pulmonary tuberculosis were chest X-rays (P < 0.00001), symptoms (P = 0.0004), age (mean: 40.8 years for TB vs. 47.5 for non-TB, P = 0.04), HIV infection (10.6% vs. 28.7%, P = 0.01), immigrant (72% vs. 55%, P = 0.03) and BCG status (P = 0.025), while multivariate analysis demonstrated that chest X-ray pattern (P < 0.00001), HIV infection (P = 0.002) and symptoms (P = 0.009) were independent predictive factors.

FUTURE PROSPECTS AND PROJECTS

From these data, a model was proposed and evaluated in the derivation cohort using the receiver operating characteristics (ROC) curve. We retrospectively studied the predictive model in two populations different from the one from which it was derived. The model would have improved sensitivity of the respiratory isolation policy from 71.4% (current respiratory isolation policy) to 82.4% and 91.1%, respectively. Prospective, multicenter studies are requested to establish the value of such a predictive model in improving the respiratory isolation policy for patients suspected of having pulmonary tuberculosis.

Nosocomial bacteremia in HIV patients: the role of peripheral venous catheters

A retrospective case-control study compared 40 human immunodeficiency virus (HV)-infected patients with 43 nosocomial bacteremias (NB) to 77 HIV-infected patients without NB. Presence of a peripheral venous catheter (PVC) was associated with occurrence of NB and was significantly more frequent in NB without an identified source. PVCs probably are an underestimated source of NB in HIV-infected patients.

Nonclassical photon statistics in single-molecule fluorescence at room temperature

The fluorescence of single terrylene molecules in a crystalline host is investigated at room temperature by scanning confocal optical microscopy. Photon arrival times are analyzed in terms of interphoton time distributions, second order correlation functions, and the variance of the photon number probability distribution. Antibunching at short times and bunching behavior for longer times is observed, associated with sub- and super-Poissonian statistics, respectively. A rate-equation analysis of the molecular level populations indicates an accelerated reverse intersystem crossing.

Cost of antimicrobial treatment for nosocomial infections based on a French prevalence survey

An estimate of the antibiotic cost of nosocomial infections (NI) was made in a university hospital group based on data collected in adult inpatients enrolled in the French national prevalence survey in 1996. Among the 6839 study patients, 636 (9.3%) presented with at least one NI, of these, data on antimicrobial treatment were available for 480. The overall daily antibiotic cost was estimated between FF 49,439 and 103,526, resulting in FF 103 to 216 per infected patient. The most expensive antibiotic treatment was prescribed in intensive care patients, for pneumonia for device-related NI, or for multi-resistant bacterial infections. Non-documented NI represented about 20% of the overall antibiotic cost. Beta-lactam antibiotics, especially third generation cephalosporins, and parenteral fluoroquinolones were the most expensive antimicrobial drugs. The cost of antibiotic treatment for NI represents a significant part of hospital expenditure that should be reduced by better control of highly expensive prescriptions.

Efficacy of prevention by high-efficiency particulate air filtration or laminar airflow against Aspergillus airborne contamination during hospital renovation

OBJECTIVE

To evaluate efficacy of laminar airflow facilities plus high-efficiency particulate air (HEPA) filtration and HEPA filtration alone in preventing environmental Aspergillus contamination during hospital renovation. To show the usefulness of environmental surveillance to facilitate protection of patients at risk for invasive pulmonary aspergillosis.

DESIGN

Prospective sampling of air and surfaces for Aspergillus conidia during 2-year period.

SETTING

A hematological department adjacent to building renovation at a university hospital.

RESULTS

1,047 air samples and 1,178 surface samples were collected from January 1996 to December 1997. Significantly more air samples were positive for Aspergillus species during the period of building renovation than during the periods before and after renovation in a unit without a protected air supply adjacent to the building work area (51.5% vs 31.7%; odds ratio [OR], 2.3; 95% confidence interval [CI95], 1.4-3.7; P<.001). A major increase in the frequency of positive air samples was also found in another adjacent unit that was protected with HEPA filtration alone (from 1.8% to 47.5%; OR, 48.9; CI95, 12-229; P<10(-7)). In addition, in this unit, the mean count of Aspergillus conidia in positive air samples increased significantly during construction (4 colony-forming units [CFU]/m3 to 24.7 CFU/m3; P=.04) and the proportion of positive surface samples showed a significant increase during renovation (from 0.4% to 9.7%; OR, 28.3; CI95, 3.4-623; P=10(-4)). However, none of 142 air samples collected during renovation in the area protected with laminar airflow plus HEPA filtration showed Aspergillus conidia. In a unit distant from the building renovation site, the results of air and surface samples were not affected by renovation.

CONCLUSION

This study showed a strong association between building renovation and an increase in environmental Aspergillus contamination. Results confirmed the high efficacy of laminar airflow plus HEPA filtration and a high air-change rate. Although filtration with HEPA was effective during normal conditions, it alone was unable to prevent the rise of Aspergillus contamination related to building renovation. This study emphasized the necessity of an environmental survey of airborne contamination related to construction, to facilitate prevention of nosocomial aspergillosis outbreaks. A standardized protocol for aerobiological surveillance is needed.

The validity of medical history, classic symptoms, and chest radiographs in predicting pulmonary tuberculosis: derivation of a pulmonary tuberculosis prediction model

STUDY OBJECTIVE

To improve the respiratory isolation policy for patients with suspected pulmonary tuberculosis (TB).

DESIGN

Prospective, descriptive, French multicenter study.

SETTING

Emergence of nosocomial outbreaks of TB.

PATIENTS

All consecutive patients admitted with suspicion of pulmonary TB.

MEASUREMENTS AND RESULTS

Medical history, social factors, symptoms, and chest radiograph (CXR) pattern (symptoms and CXR both scored as typical of pulmonary TB, compatible, negative, or atypical) were obtained on admission. Serial morning sputa were collected. Of the 211 patients, 47 (22.3%) had culture-proven pulmonary TB, including 31 (14.7%) with a positive smear. Mean age was 46.2 years; 52 patients were HIV positive (24.6%). The sensitivity of the respiratory isolation policy was 71.4%, specificity was 51.7%, negative predictive value (NPV) was 88.2%, and positive predictive value (PPV) was 26.3%. On univariate analysis, predictive factors of culture-proven pulmonary TB were CXR (p < 0.00001), symptoms (p = 0.0004), age (mean, 40.8 years for TB patients vs 47.5 years for non-TB patients; p = 0.04), absence of HIV infection (89.4% vs 71.3%; p = 0.01), immigrant status (72% vs 55%; p = 0.03), and bacillus Calmette-Guérin status (p = 0.025). On multivariate analysis, CXR pattern (p < 0.00001), HIV infection (p = 0.002), and symptoms (p = 0.009) remained independently predictive. Based on these data, a model was proposed using a receiver operating characteristics curve. In the derivation cohort, the sensitivity and NPV of the model in detecting smear-positive pulmonary TB would have been 100%. The specificity and PPV would have been 48.4% and 25%, respectively. The model performed less well when evaluated on two retrospective groups, but its sensitivity remained above that of the current respiratory isolation policy (91.1% and 82.4% for the retrospective groups vs 71.1% for the current policy).

CONCLUSIONS

Improved interpretation of clinical and radiologic data available on patient admission could improve adequacy of respiratory isolation. A prediction model is proposed.

Preparation and characterization of dipalmitoylphosphatidylcholine liposomes containing interleukin-2

Human recombinant interleukin-2 (IL-2) has been associated or mixed with small unilamellar vesicles prepared from dipalmitoylphosphatidylcholine (DPPC). Whatever the mode of IL-2 introduction, a considerable proportion of the added protein was associated with the liposomes, as determined by gel filtration and ultrafiltration/centrifugation, suggesting that IL-2 can interact with the lipid bilayer as well as being entrapped within the aqueous phase. Moreover, IL-2 prevented the aggregation/fusion of the vesicles at 4 degrees C. Liposome-associated protein was partially protected from digestion by pepsin, especially at the C-terminal, since no fluorescence emission from the tryptophan in this region was detected in the resulting peptides after separation by HPLC. Such systems could constitute a sustained release form of IL-2 for immunotherapy.