Escherichia coli strains belonging to phylogenetic group B2 have superior capacity to persist in the intestinal microflora of infants

Escherichia coli strains segregate into 4 phylogenetic groups, designated "A," "B1," "B2," and "D." Pathogenic strains belong to group B2 and, to a lesser extent, group D, which more frequently carry virulence-factor genes than do group A strains and group B1 strains. This study investigated whether the capacity of E. coli to persist in the human intestine is related to its phylogenetic type. Resident (n=58) and transient (n=19) commensal E. coli strains isolated during a longitudinal study of 70 Swedish infants and previously tested for virulence-factor-gene carriage were tested for phylogenetic type. Of the strains resident in the intestinal microflora, 60% belonged to group B2, compared with only 21% of the transient strains (P=.004). In logistic regression, group B2 type predicted persistence in the intestinal microflora, independent of carriage of all investigated virulence-factor genes, including genes for P fimbriae (P=.03). Thus, group B2 strains appear to possess yet unidentified traits that enhance their survival in the human intestine.     

Human adenosine A(3) receptor leads to intracellular Ca(2+) mobilization but is insufficient to activate the signaling pathway via phosphoinositide 3-kinase gamma in mice

Selective antagonists for the adenosine A(3) receptor (A3AR), a member of the G protein-coupled receptors, have been indicated as potential drugs for anti-asthma or anti-inflammation. However, potent antagonists for the rodent A3AR have not been identified. To evaluate the pharmacological effects of human A3AR antagonists in mice, we here generated A3AR-humanized mice, in which the mouse A3AR gene was replaced by its human counterpart. The expression levels of human A3AR in the A3AR-humanized mice were equivalent to those of mouse A3AR in wild-type mice. Elevation of the intracellular Ca(2+) concentration induced by an A3AR agonist was observed in bone marrow-derived mast cells from the A3AR-humanized mice and this Ca(2+) mobilization was completely antagonized by a human A3AR antagonist. However, antigen-dependent degranulation was not potentiated by the A3AR agonist in the mast cells from A3AR-humanized mice. The agonist-stimulated human A3AR did not lead to the phosphorylation of either extracellular signal-regulated kinase 1/2 or protein kinase B in A3AR-humanized mice. The rate of human A3AR internalization in the mast cells was also markedly decreased compared with that of mouse A3AR in the mast cells. These results demonstrate that the human A3AR is insufficient to activate phosphoinositide 3-kinase gamma-dependent signaling pathways in mice, probably due to the uncoupling of member(s) of the G proteins, which are capable of activating phosphoinositide 3-kinase gamma, to the human A3AR, despite the mouse G protein(s) responsible for the Ca(2+) elevation are coupled with the human A3AR.     

A novel HIV-1 reporter virus with a membrane-bound Gaussia princeps luciferase

HIV-1 reporter viruses are a critical tool for investigating HIV-1 infection. By having a reporter gene incorporated into the HIV-1 genome, the expressed reporter protein acts as a specific tag, thus enabling specific detection of HIV-1 infected cells. Currently existing HIV-1 reporter viruses utilize reporters for the detection of HIV-1 infected cells by a single assay. A reporter virus enabling the detection of viral particles as well as HIV-1 infected cells by two assays can be more versatile for many applications. In this report, a novel reporter HIV-1 was generated by introducing a membrane-anchored form of the Gaussia princeps luciferase gene (mGluc) upstream of the nef gene in the HIV-1(NL4-3) genome using a picornaviral 2A-like sequence. The resulting HIV-1(NL4-3mGluc) virus expresses G. princeps luciferase efficiently on viral membrane and the cell surface of infected human T cell lines and primary peripheral blood mononuclear cells. This HIV-1 reporter is replication competent and the reporter gene mGluc is expressed during multiple rounds of infection. Importantly, viral particles can be detected by bioluminescence and infected cells can be detected simultaneously by bioluminescence and flow cytometric assays. With the versatility of two sensitive detection methods, this novel luciferase reporter has many applications such as cell-based screening for anti-HIV-1 agents or studies of HIV-1 pathogenicity.     

A Systematic Review and Meta-analysis of Intralesional Versus Wide Resection for Intramedullary Grade I Chondrosarcoma of the Extremities

Background

The surgical management of grade I intramedullary chondrosarcoma of bone remains controversial. The purpose of this study was to perform a systematic review and meta-analysis of published data to determine the oncologic outcomes of intralesional versus wide resection for grade I intramedullary chondrosarcoma.

Methods

Literature searches were performed through Medline, EMBASE, and the Cochrane Database. Cohort studies in which one patient group with grade I chondrosarcoma underwent wide resection and one underwent intralesional curettage were included. Two reviewers independently assessed all eligible papers with the Newcastle-Ottawa Quality Assessment Scale for Cohort Studies. The outcome measures were the pooled odds ratio and 95% confidence intervals for the risk of local recurrence and metastasis calculated through the random-effects method.

Results

Five eligible studies were identified including a total of 190 patients, 78 of whom underwent intralesional resection and 112 of whom underwent wide resection. Only one pelvic lesion was identified, which underwent wide resection. There were a total of five local recurrences and three metastases. The risk for local recurrence and metastasis did not differ significantly between the two groups, with an odds ratio for intralesional resection of 2.26 (95% confidence interval, 0.41–12.62) and 0.44 (95% confidence interval, 0.04–5.21) respectively.

Conclusions

Intralesional curettage as an alternative to wide resection for extrapelvic grade I chondrosarcoma of bone does not greatly increase the risk for local recurrence or metastasis. Overall effect estimates, however, should be interpreted with caution as a result of the relatively small number of events.     

Quality of assessment of randomized controlled trials in blood conservation after joint arthroplasty

Blood transfusion after joint arthroplasty occurs in up to two thirds of patients. We conducted a systematic review of the literature to determine the methodological quality of published randomized controlled trials (RCTs). We searched MEDLINE, EMBASE, and Cochrane to identify RCTs in arthroplasty with blood conservation as the primary outcome from 2001 to 2007. Methodological quality was evaluated using the Detsky index. We identified 62 RCTs. The mean Detsky score was 73% ± 14%. Epidemiology affiliation (P = .003), funding support (<.001), and year of publication (<.001) were the predictors of reporting quality, predicting 46% of the variability (R² = 0.46). This suggests poor reporting quality of trials in blood conservation. The inclusion of an epidemiologist or a biostatistician for the design of a trial is strongly recommended.     

A cost comparison of off-pump CABG versus on-pump CABG at one-year: The Canadian off-pump CABG registry

BACKGROUND: Evidence suggests that off-pump coronary artery bypass graft surgery (CABG) is as safe and effective as on-pump CABG, and the cost of initial hospitalization for off-pump CABG is less expensive than on-pump CABG. However, it is uncertain whether the cost savings are sustained over a longer period of time. OBJECTIVE: To assess in-hospital and one-year direct medical costs of off-pump CABG versus on-pump CABG in the context of the Canadian health care system. METHODS AND RESULTS: From March 2001 to December 2002, 1657 consecutive patients enrolled in the Canadian Off-Pump CABG Registry were compared with 1693 consecutive on-pump patients from Hamilton Health Sciences CABG database. At one year, patients of both groups were followed by telephone interview. An economic analysis was conducted from the perspective of the Ontario Ministry of Health and Long-Term Care, and the data analysis was based on propensity score-matched registry patients (1233 pairs) to ensure the comparability of the two study groups. Clinical event and resource use information was collected from all patients. Unit costs from the Hamilton Health Sciences case-costing system were used to estimate hospital costs; all costs were reported in 2003 Canadian dollars. Sensitivity analyses were performed to account for uncertainties. The cost of initial hospitalization for off-pump CABG was significantly less than on-pump CABG (11,744 dollars versus 13,720 dollars, P < 0.001). Although follow-up costs were similar between the groups, the one-year total cost per patient for off-pump CABG remained significantly less than on-pump CABG (12,063 dollars versus 14,141 dollars, P < 0.001). CONCLUSION: Off-pump CABG offers significant savings during initial hospitalization that are also sustained after one year.     

Caring behaviors of burn nurses and the related factors

This study aims to explore and describe nurses' perceptions of their caring behaviors and related factors in several Tehran burn units. Grounded theory was used as the method of analysis. Thirty-eight participants were recruited. Data was generated by unstructured interviews and participant observations, and analyzed by constant comparison. Results revealed that responses to burnout and the type of caring behavior exhibited were affected most markedly by the personal characteristics of nurses and patients and the interaction between these two factors. Long-standing and intense organizational pressures in the burn units of Tehran, in addition to the sensitivity of nurses' characteristics to these pressures, suggest that attributing more importance to the social, political and ethical aspects of caring may aid in executing stress reduction programs and improving nurses' morale.     

Mild hypohydration induced by exercise in the heat attenuates autonomic thermoregulatory responses to the heat, but not thermal pleasantness in humans

Hypohydration caused by exercise in the heat attenuates autonomic thermoregulation such as sweating and skin blood flow in humans. In contrast, it remains unknown if behavioral thermoregulation is modulated during hypohydration. We assume that thermal unpleasantness could drive the behavioral response, and would also be modulated during hypohydration. Nine healthy young men participated in the present study. Body and skin temperatures were monitored. Ratings of thermal sensation and pleasantness were conducted. After ∼ 45 min rest at 27 °C, they performed 50-min cycling exercise, which was at the level of 40% of heart rate range at 35 °C (hypohydration trial) or at the level of 10% of heart rate range at 23 °C (control trial), respectively. Subjects returned to the rest at 27 °C, and the ambient temperature was then changed from 22 to 38 °C. Body weight decreased by 0.9 ± 0.1% immediately after exercise in the hypohydration trial and 0.3 ± 0.1% in the control trial. In the cold, no significant difference in thermal sensation or pleasantness was observed between trials. There was no significant difference in thermal pleasantness between trials in the heat, although thermal sensation in the heat (32.5-36 °C) was significantly lower in the hypohydration trial than in the control trial. In addition, laser Doppler flow of the skin and sweat rate were attenuated in the heat in the hypohydration trial. These results may indicate that mild hypohydration after exercise in the heat has no influence on behavioral responses to the heat.