Serum-free media supplements carry miRNAs that co-purify with extracellular vesicles

Recent studies on extracellular RNA raised awareness that extracellular vesicles (EVs) isolated from cultured cells may co-purify RNAs derived from media supplements such as fetal bovine serum (FBS) confounding EV-associated RNA. Defined culture media supplemented with a range of nutrient components provide an alternative to FBS addition and allow EV-collection under full medium conditions avoiding starvation and cell stress during the collection period. However, the potential contribution of serum-free media supplements to EV-RNA contamination has remained elusive and has never been assessed. Here, we report that RNA isolated from EVs harvested from cells under serum-replacement conditions includes miRNA contaminants carried into the sample by defined media components. Subjecting unconditioned, EV-free medium to differential centrifugation followed by reverse transcription quantitative PCR (RT-qPCR) on RNA isolated from the pellet resulted in detection of miRNAs that had been classified as EV-enriched by RNA-seq or RT-qPCR of an isolated EV-fraction. Ribonuclease (RNase-A) and detergent treatment removed most but not all of the contaminating miRNAs. Further analysis of the defined media constituents identified Catalase as a main source of miRNAs co-isolating together with EVs. Hence, miRNA contaminants can be carried into EV-samples even under serum-free harvesting conditions using culture media that are expected to be chemically defined. Formulation of miRNA-free media supplements may provide a solution to collect EVs clean from confounding miRNAs, which however still remains a challenging task. Differential analysis of EVs collected under full medium and supplement-deprived conditions appears to provide a strategy to discriminate confounding and EV-associated RNA. In conclusion, we recommend careful re-evaluation and validation of EV small RNA-seq and RT-qPCR datasets by determining potential medium background.

[Transabdominal cervico-isthmic cerclage: 13 cases at Rouen University Hospital]

OBJECTIVE

The aim of this study was to describe our experience with cervico-isthmic cerclage by abdominal approach and to assess this efficacy.

PATIENTS AND METHODS

A retrospective analysis of 13 transabdominal cerclages (eight by laparotomy and five by laparoscopy), seven cases performed before pregnancy and six cases between 12 and 14 weeks of gestation, between 2004 and 2009. We analyzed the previous obstetric accidents, the etiology of cervical incompetence and the patient outcome after cerclage.

RESULTS

Median age of the patients was 35 years [27-42 years]. Patients had an average of pregnancy 4,2 [1-7], with 3,3 previous fetal losses or preterm delivery. Eighty percent had a prior failed transvaginal cerclage. The mean operative time of laparotomic cerclage was 100 minutes and 94 minutes by laparoscopy, with a mean hospitalization time respectively of seven and 2,5 days. No operative complication was reported. Eleven women were pregnant after cervico-isthmic cerclage: nine deliveries by caesarean section at term, and two preterm births between 34 and 37 weeks of gestation. Two patients are looking for being pregnant and one of those is currently doing a procedure of IVF.

DISCUSSION AND CONCLUSION

Transabdominal cervico-isthmic cerclage is an alternative technique for the management of cervical incompetence after failed vaginal cerclage. Our data indicated that the cervico-isthmic cerclage placed laparoscopically compares favorably with the laparotomy approach in regard to operative technique and risk of complications.

Prognostic significance of the “surprise” question in cancer patients

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Background: In patients with advanced cancer, failure to accurately estimate and communicate prognoses can lead to overly aggressive care at the end of life with less attention to important palliative care issues such as pain and symptom management and patients’ values and goals for care. The “surprise” question—would I be surprised if this patient died in the next year?—has been recognized as an innovation to improve end-of-life care in the primary care population by identifying patients with a poor prognosis who are appropriate for palliative care. It has not been previously tested in cancer patients. The purposes of this study were to determine the feasibility and outcomes of the use of the “surprise” question in a cancer center population. Methods: Between July and November 2007, oncologists prospectively classified consecutive breast, lung, and colon cancer patients being seen at the Mary Babb Randolph Cancer Center of West Virginia University into “Yes” and “No” groups based on the surprise question. Patients were followed and their status at the end of one year-alive or dead-was determined along with patient demographics, type of cancer, and stage at presentation. A multivariate Cox proportional hazards regression analysis was used to identify variables associated with patient death. Results: Oncologists classified 826 of 853 prospective patients (97%), with 131 (16%) classified into the “No” group and 695 (84%) into the “Yes” group. At the end of the year, 71 patients had died; 41% of the “No” patients compared to 3% of the “Yes” patients (P <.001). The surprise question ‘No‘ response was more predictive of patient death than stage of cancer, cancer type, or age (hazard ratio 7.53, P value <.001). The “Yes” patients lived longer than the “No” patients (359.8±32.8 days versus 270±131.5 days, P <.001). The sensitivity of the surprise question “No” response was 75% and the specificity was 90%. Conclusions: We conclude that the surprise question is a simple, feasible, and effective tool to identify cancer patients with the worst prognoses who should receive the highest priority for palliative care interventions, particularly advance care planning.

No significant financial relationships to disclose.

[Cytological screening of uterine cervical cancer by samples in liquid medium (CytoRich). Preliminary study of a series of 111 292 patients]

We report on the preliminary results of a series of 111,292 patients who benefited from a liquid medium sample (CytoRich) for cervical cancer screening. The number of dubious or limited smears was reduced by 0.03% and 0.53% respectively. The junction zone was better explored, and metaplastic changes were observed in 35.71% of the cases. This method improved the identification of low-grade lesions by +56% (2751/111,292; 2.47%) and of high-grade lesions by +75% (860/111,292; 0.77%), with a reduction in the number of ASCUS/AGUS by -44% (2065/111,292; 1.85%). This preliminary study confirms the results already published. The results demonstrating cytohistological correlation should prove to be a decisive factor, enabling the testing of the sensitivity and specificity of this technique. It will then be possible to envisage a future 'new paradigm' for screening cervical cancer as the result of a liquid medium sample, computer-assisted screening and HPV viral identification by Hybrid capture II.

Arachidonic acid stimulates short-circuit current in the isolated toad urinary bladder

The effects of the prostaglandin (PG) precursors 5,8,11,14-eicosatetraenoic acid (arachidonic acid) and 8,11,14-eicosatrienoic acid (dihomo-gamma-linolenic acid) on short-circuit current (SCC) were assessed in the isolated toad urinary bladder. Arachidonic acid added to the serosal bathing media increased SCC and immunoreactive PGE2 (iPGE2) synthesis in a dose-related manner. Pretreatment with eicosatetraynoic acid (50 micrometer), a prostaglandin synthetase inhibitor, completely blocked the arachidonic acid-induced increase in SCC and significantly reduced iPGE2 synthesis (P less than .025, n = 9). Eicosatrienoic acid (100 micrometer) was equieffective with arachidonic acid in increasing SCC and iPGE1 synthesis. Addition of arachidonic acid (100 micrometer) to the mucosal bathing media produced no significant increase in SCC and only increased iPGE2 synthesis from 0.03 +/- 0.01 pmol/min (n = 5) to 0.31 +/- 0.03 pmol/min, a level not different from the serosal basal rate of iPGE synthesis (0.21 +/- 0.16 pmol/min, n = 5). PGE1 (1 micrometer) added to the serosal media significantly increased SCC reaching a maximum increase of 157 +/- 43% (P less than .025, n = 6) by 30 min whereas addition to the mucosal media resulted in a delayed (60 min) and lesser maximum increase (59 +/- 19%, P less than .02, n = 6). It is concluded that prostaglandin precursors increase SCC and PGE synthesis in the isolated toad urinary bladder. However, the present data do not support PGE as the metabolite responsible for the increase in SCC.