Transplant tolerance is associated with reduced expression of cystathionine-γ-lyase that controls IL-12 production by dendritic cells and TH-1 immune responses

Antigen-activated T lymphocytes undergo an immune or tolerogeneic response in part according to the activation status of their antigen-presenting cells. However, factors controlling the activation of antigen-presenting cells are not fully understood. In this study, we demonstrate that immune tolerance after organ allotransplantation in the rat is associated with a repressed intragraft expression of several enzymes of the trans-sulfuration pathway, including cystathionine γ-lyase (CSE). The pharmacologic blockade of CSE with propargylglycine delayed heart allograft rejection and abrogated type IV hypersensitivity but did not modify antibody responses, and was associated with a selective inhibition of the TH-1 type factors T-bet, IL-12, and IFN-γ. IL-12 repression could also be induced by propargylglycine in vitro in monocytes and dendritic cells (DCs), a phenomenon not mediated by changes to nuclear factor-κ B or hydrogen sulfide but that occurred together with a modulation of intracellular cysteine content. Intracellular cysteine levels were predominantly controlled in DCs by CSE activity, together with extracellular import via the X(c)(-) transporter. Our results indicate that CSE plays a critical role in regulating IL-12 in monocytes and DCs and is down-modulated in transplant tolerance, presumably participating in the maintenance of the tolerant state.     

An end-joining repair mechanism in Escherichia coli

Bridging broken DNA ends via nonhomologous end-joining (NHEJ) contributes to the evolution and stability of eukaryote genomes. Although some bacteria possess a simplified NHEJ mechanism, the human commensal Escherichia coli is thought to rely exclusively on homology-directed mechanisms to repair DNA double-strand breaks (DSBs). We show here that laboratory and pathogenic E. coli strains possess a distinct end-joining activity that repairs DSBs and generates genome rearrangements. This mechanism, named alternative end-joining (A-EJ), does not rely on the key NHEJ proteins Ku and Ligase-D which are absent in E. coli. Differently from classical NHEJ, A-EJ is characterized by extensive end-resection largely due to RecBCD, by overwhelming usage of microhomology and extremely rare DNA synthesis. We also show that A-EJ is dependent on the essential Ligase-A and independent on Ligase-B. Importantly, mutagenic repair requires a functional Ligase-A. Although generally mutagenic, accurate A-EJ also occurs and is frequent in some pathogenic bacteria. Furthermore, we show the acquisition of an antibiotic-resistance gene via A-EJ, refuting the notion that bacteria gain exogenous sequences only by recombination-dependent mechanisms. This finding demonstrates that E. coli can integrate unrelated, nonhomologous exogenous sequences by end-joining and it provides an alternative strategy for horizontal gene transfer in the bacterial genome. Thus, A-EJ contributes to bacterial genome evolution and adaptation to environmental challenges. Interestingly, the key features of A-EJ also appear in A-NHEJ, an alternative end-joining mechanism implicated in chromosomal translocations associated with human malignancies, and we propose that this mutagenic repair might have originated in bacteria.     

A Novel Smartphone Accelerometer Application for Low-Intensity Activity and Energy Expenditure Estimations in Overweight and Obese Adults

Physical inactivity and sedentary behaviors are on the rise worldwide and contribute to the current overweight and obesity scourge. The loss of healthy life style benchmarks and the lack of the need to move make it necessary to provide feedback about physical and sedentary activities in order to promote active ways of life. The aim of this study was to develop a specific function adapted to overweight and obese people to identify four physical activity (PA) categories and to estimate the associated total energy expenditure (TEE). This function used accelerometry data collected from a smartphone to evaluate activity intensity and length, and TEE. The performance of the proposed function was estimated according to two references (Armband® and FitmatePro®) under controlled conditions (CC) for a 1.5-h scenario, and to the Armband® device in free-living conditions (FLC) over a 12-h monitoring period. The experiments were carried out with overweight and obese volunteers: 13 in CC and 27 in FLC. The evaluation differences in time spent in each category were lower than 7% in CC and 6% in FLC, in comparison to the Armband® and FitmatePro® references. The TEE mean gap in absolute value between the function and the two references was 9.3% and 11.5% in CC, and 8.5% according to Armband® in FLC.     

Equipment Failure: Causes and Consequences in Endoscopic Gynecologic Surgery

Study ObjectiveTo determine the incidence of equipment failure in gynecologic endoscopy and investigate causes and consequences.DesignA prospective observational single-center study between January and April 2006.SettingGynecologic surgery department of a university hospital.InterventionsIn all, 116 endoscopic interventions were included: 62 laparoscopies, 51 operative hysteroscopies, and 3 fertiloscopies. Emergency and equipment testing procedures were excluded.Measurements and Main ResultsEquipment malfunctions were divided into 4 categories with regard to imaging, transmission of fluids and light, the electric circuit, and surgical instruments. We also found cases with faulty connections between elements. Factors including human error, loss of time, and actual or potential consequences were analyzed. At least 1 equipment failure was noted in 38.8% of operative procedures, 41.9% of laparoscopies, and 37.3% of hysteroscopies. Fluid, gas, and light transmission was faulty in 36.2%, surgical instruments in 29.3%, the electric circuit in 22.4%, and imaging in 12.1%. Of malfunctions, 46.6% were a result of faulty connection between 2 elements. The most common cause for concern was bipolar forceps and cables in laparoscopy (42.3%) and the assembly of small parts in hysteroscopy (47.4%). Personnel were implicated in 43% of cases (nurses in 72%, surgeons in 12%, both in 16%). One equipment failure increased the total duration of laparoscopy by 7% and of hysteroscopy by 20%. The mean delay was 5.6 ± 4.0 minutes by equipment failure. Of the incidences, 19% could have led to serious complications for the patient; however, no morbidity or mortality actually occurred in this series.ConclusionEquipment malfunction is common in endoscopic surgery and concerns both laparoscopy and hysteroscopy. Consequences are potentially serious. It is mandatory to identify and rectify causes of equipment failure so as to optimize the daily use of endoscopic instruments and improve patient safety. The implementation of systematic checklists is currently under evaluation.     

Which patients with colorectal cancer are followed up by general practitioners? A population-based study.

The aim of the study was to assess the contribution of general practitioners in the surveillance of colorectal cancer, and to examine characteristics and survival of patients with routine general practitioner follow-up. This French registry-based study included 389 patients diagnosed with first colorectal cancer in 1998 and free of disease at least 6 months after curative surgery. For each physician involved, medical records were thoroughly reviewed to collect information about the clinical examinations and follow-up tests prescribed within 3 years after surgery or until death or detection of recurrence. Five-year vital status was obtained through registry records. The proportion of routine clinical examinations performed by general practitioners increased from 35% in the first year to 65% in the third year. Patients having undergone regular general practitioner routine examinations (> or =one examination every 6-month period) had significantly less advanced disease (odds ratio: 0.45; 95% confidence interval: 0.21-0.96), preoperative complications (odds ratio: 0.28; 95% confidence interval: 0.08-0.91) and routine examinations by gastroenterologists/oncologists (odds ratio: 0.37; 95% confidence interval: 0.14-0.98) compared with those without general practitioner examinations. Routine general practitioner follow-up had no influence on 3 and 5-year survival. General practitioners detected significantly more recurrences than specialists in patients over 75 and in those presenting symptoms. French general practitioners are widely involved in the surveillance of patients with early-stage colorectal cancer, without any unfavourable impact on the patient's survival. Some suggestions exist that continuing education in oncology may increase the implication of general practitioners in colorectal cancer surveillance.     

Case-control study of lymphoid neoplasm in three French areas: description, alcohol and tobacco consumption.

A multi-centre hospital-based case-control study was conducted in three regions of France between 2000 and 2003 in order to establish the risk factors of lymphoid neoplasms. We report here results concerning alcohol and tobacco consumption. A total of 298 cases and 276 controls, case-matched by inclusion centre, age and sex were included. Cases were classified according to the World Health Organization classification and validated by an expert panel of eight pathologists. Overall alcohol intake did not incur any risk increase for non-Hodgkin's lymphoma. Wine consumption marginally increased the risk of follicular lymphoma [odds ratio=2.19 (0.83-5.80)], with a higher risk for drinkers who started before the age of 20 years [odds ratio=4.04 (1.19-13.76)] and for drinkers who consumed more than 19 g of alcohol per day [odds ratio=4.37 (1.04-18.45)]. Beer and spirit consumption was not linked to non-Hodgkin's lymphoma risk. Tobacco consumption did not show a risk increase. The risk increase of follicular lymphoma due to wine consumption was new. We discuss this risk based on the French context, France being the European country with the highest alcohol consumption, particularly of wine.     

Technical evaluation of thymidine kinase assay in cytosols from breast cancers

Pilot retrospective studies have pointed to the prognostic value of thymidine kinase (TK) in breast cancer. We studied the Prolifigen TK-REA assay (Sangtec Medical, Sweden), usually applied to serum, for TK analysis in breast cancer cytosols. Reproducibility was good, provided that small volume pipetting was performed carefully. The TK assay was not influenced by the short-term storage of cytosols in liquid nitrogen or at −80 °C. However, some steps appeared critical for good laboratory practice. The TK level was affected by thawing the cytosols more than twice. Tumour storage in liquid nitrogen should be preferred over storage at −80 °C. The components of the homogenisation buffer, especially sodium molybdate and KCl can have a marked influence on results. Finally, linearity problems arose with some cytosols. Thus, although assay of TK in cytosols is aparently simple, care must be taken in practice. The TK-REA kit should be standardised before widespread use in breast cancer.