Cell cycle dynamics during diapause entry and exit in an annual killifish revealed by FUCCI technology

Background: Annual killifishes are adapted to surviving and reproducing over alternating dry and wet seasons. During the dry season, all adults die and desiccation-resistant embryos remain encased in dry mud for months or years in a state of diapause where their development is halted in anticipation of the months that have to elapse before their habitats are flooded again. Embryonic development of annual killifishes deviates from canonical teleost development. Epiblast cells disperse during epiboly, and a "dispersed phase" precedes gastrulation. In addition, annual fish have the ability to enter diapause and block embryonic development at the dispersed phase (diapause I), mid-somitogenesis (diapause II) and the final phase of development (diapause III). Developmental transitions associated with diapause entry and exit can be linked with cell cycle events. Here we set to image this transition in living embryos. Results: To visibly explore cell cycle dynamics during killifish development in depth, we created a stable transgenic line in Nothobranchius furzeri that expresses two fluorescent reporters, one for the G1 phase and one for the S/G2 phases of the cell cycle, respectively (Fluorescent Ubiquitination-based Cell Cycle Indicator, FUCCI). Using this tool, we observed that, during epiboly, epiblast cells progressively become quiescent and exit the cell cycle. All embryos transit through a phase where dispersed cells migrate, without showing any mitotic activity, possibly blocked in the G1 phase (diapause I). Thereafter, exit from diapause I is synchronous and cells enter directly into the S phase without transiting through G1. The developmental trajectories of embryos entering diapause and of those that continue to develop are different. In particular, embryos entering diapause have reduced growth along the medio-lateral axis. Finally, exit from diapause II is synchronous for all cells and is characterized by a burst of mitotic activity and growth along the medio-lateral axis such that, by the end of this phase, the morphology of the embryos is identical to that of direct-developing embryos. Conclusions: Our study reveals surprising levels of coordination of cellular dynamics during diapause and provides a reference framework for further developmental analyses of this remarkable developmental quiescent state

The sources of sex differences in aging in annual fishes

Intersexual differences in life span (age at death) and aging (increase in mortality risk associated with functional deterioration) are widespread among animals, from nematodes to humans. Males often live shorter than females, but there is substantial unexplained variation among species and populations. Despite extensive research, it is poorly understood how life span differences between the sexes are modulated by an interplay among genetic, environmental and social factors. The goal of our study was to test how sex differences in life span and ageing are modulated by social and environmental factors, and by intrinsic differences between males and females. To disentangle the complex basis of sex differences in life span and aging, we combined comparative data from sex ratios in 367 natural populations of four species of African annual killifish with experimental results on sex differences in life span and aging from eight laboratory populations tested in treatments that varied social and environmental conditions. In the wild, females consistently outlived males. In captivity, sex-specific mortality depended on social conditions. In social-housed experimental groups, male-biased mortality persisted in two aggressive species, but ceased in two placid species. When social and physical contacts were prevented by housing all fish individually, male-biased mortality ceased in all four species. This outcome held across benign and challenging environmental conditions. Fitting demographic survival models revealed that increased baseline mortality was primarily responsible for a shorter male life span in social-housing conditions. The timing and rate of aging were not different between the sexes. No marker of functional aging we recorded in our study (lipofuscin accumulation, proliferative changes in kidney and liver) differed between males and females, despite their previously confirmed association with functional aging in Nothobranchius killifish. We show that sex differences in life span and aging in killifish are driven by a combination of social and environmental conditions, rather than differential functional aging. They are primarily linked to sexual selection but precipitated through multiple processes (predation, social interference). This demonstrates how sex-specific mortality varies among species even within an ecologically and evolutionary discrete lineage and explains how external factors mediate this difference

Relationship between retinal inner nuclear layer, age, and disease activity in progressive MS

Objective: To investigate whether inner nuclear layer (INL) thickness as assessed with optical coherence tomography differs between patients with progressive MS (P-MS) according to age and disease activity. Methods: In this retrospective longitudinal analysis, differences in terms of peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer + inner plexiform layer (GCIPL), INL and T1/T2 lesion volumes (T1LV/T2LV) were assessed between 84 patients with P-MS and 36 sex- and age-matched healthy controls (HCs) and between patients stratified according to age (cut-off: 51 years) and evidence of clinical/MRI activity in the previous 12 months RESULTS: pRNFL and GCIPL thickness were significantly lower in patients with P-MS than in HCs (p = 0.003 and p < 0.0001, respectively). INL was significantly thicker in patients aged < 51 years compared to the older ones and HCs (38.2 vs 36.5 and 36.7 μm; p = 0.038 and p = 0.04, respectively) and in those who presented MRI activity (new T2/gadolinium-enhancing lesions) in the previous 12 months compared to the ones who did not and HCs (39.5 vs 36.4 and 36.7 μm; p = 0.003 and p = 0.008, respectively). Recent MRI activity was significantly predicted by greater INL thickness (Nagelkerke R2 0.36, p = 0.001). Conclusions: INL thickness was higher in younger patients with P-MS with recent MRI activity, a criterion used in previous studies to identify a specific subset of patients with P-MS who best responded to disease-modifying treatment. If this finding is confirmed, we suggest that INL thickness might be a useful tool in stratification of patients with P-MS for current and experimental treatment choice

A phase II randomised trial of 5-fluorouracil with or without interferon alpha-2a in advanced colorectal cancer.

With the association of 5-fluorouracil (5-FU) and alpha-interferon (IFN), objective responses as high as 26 63% have been reported in untreated patients with advanced colorectal cancer. However, grade 3-4 toxicity has also been reported. We have conducted a prospective phase II randomised study comparing 5-FU to 5-FU + IFN, to investigate whether the addition of IFN to a weekly 5-FU regimen devoid of significant toxicity used at our institutions could improve the effectiveness of 5-FU while maintaining acceptable toxicity. Patients with histologically proven advanced colorectal carcinoma were randomised to receive 5-FU 500 mg m-2 intravenous (i.v.) bolus on days 1-5 followed by 5-FU 500 mg m-2 i.v. bolus weekly from day 15, with or without IFN alpha-2a intramuscularly (i.m.) 1.5 mU daily on days 6-12 and 3 mU i.m. daily thereafter. The treatment was administered on an outpatient basis. Response was evaluated every 3 months, and treatment continued until progression or after two consecutive judgements of stable disease. Response rate was the main end point of the study. Of 141 patients eligible, 72 were randomised to 5-FU alone (arm A) and 69 to 5-FU + IFN (arm B). Responses were 9/72 (12.5%) in arm A and 6/69 (8.7%) in arm B; complete responses were three in arm A and two in arm B. Progression-free survival (median 4 months) and survival (median 12 months) were identical in the two arms. Toxicity was almost absent in arm A and moderate in arm B, represented mainly by haematological toxicity (usually leucopenia). In conclusion, overall survival was good in both arms of treatment and toxicity was moderate. While the response rate with 5-FU alone was in accord with the literature data, response to 5-FU + IFN was lower than expected. At least at this dosage and schedule, the association of 5-FU and IFN is no better than 5-FU alone and is of no clinical interest

Demand for the quality conservation of Venice, Italy, according to different nationalities.

This paper focuses on visitor demand for the quality conservation of Venice according to different nationalities. The vast majority of visitors to Venice are foreigners (both tourists and day-visitors) who come from all over the world. In this research they are mainly categorized as non-Italian Europeans or non-Europeans. A specific theoretical model, in which quality conservation is provided publicly and also privately through donations, is presented for nationals and for foreigners. The data are obtained from a contingent valuation survey carried out in Venice, the aim of which was to estimate visitors' willingness to donate (WTD) to the Venice flood defence programme. Demand functions are estimated by applying a twostage regression model. The authors show that the majority of visitors are willing to donate. On average, Italians and non-Europeans would donate more than non-Italian Europeans. As expected, these visitor categories have different mean WTD and different behavioural functions which are affected by attitudinal and economic variables. Bequest value is the main donation motive. Those who identify this as a donation motive, on average, state the highest WTD and the highest degree of certainty to donate. This result seems to confirm empirically the validity of the sustainable development principle applied to the management of Venice as a cultural tourist site

High tandem repeat content in the genome of the short-lived annual fish Nothobranchius furzeri: a new vertebrate model for aging research

A genomic analysis of the annual fish Nothobranchius furzeri, a vertebrate with the shortest known life span in captivity and which may provide a new model organism for aging research

Medical student teaching in the UK: how well are newly qualified doctors prepared for their role caring for patients with cancer in hospital?

A number of studies have identified problems with undergraduate oncology teaching. We have investigated how well prepared newly qualified doctors (first foundation year, or FY1 doctors) are for treating patients with cancer. Twenty-five FY1 doctors and 15 senior doctors participated in interviews. We turned the emergent themes into a questionnaire for all 5143 UK FY1 doctors in 2005. The response rate was 43% (2062 responses). Sixty-one percent of FY1 doctors had received oncology teaching at medical school, but 31% recalled seeing fewer than 10 patients with cancer. Forty percent of FY1 doctors felt prepared for looking after patients with cancer. Sixty-five percent felt prepared for diagnosing cancer, 15% felt they knew enough about chemotherapy and radiotherapy, and 11% felt prepared for dealing with oncological emergencies. Respondents believed medical students should learn about symptom control (71%) and communication skills (41%). Respondents who had received oncology teaching were more likely to feel prepared for looking after patients with cancer (OR 1.52; 95% CI 1.14–2.04). Preparedness also correlated with exposure to patients with cancer (OR 1.48; 95% CI 1.22–1.79). We have found worryingly low levels of exposure of medical students to patients with cancer. First foundation year doctors lack knowledge about cancer care and symptom control. Oncologists should maintain involvement in undergraduate teaching, and encourage greater involvement of patients in this teaching

Intensive weekly chemotherapy is not effective in advanced pancreatic cancer patients: a report from the Italian Group for the Study of Digestive Tract Cancer (GISCAD)

Twenty-two patients, with locally advanced unresectable and/or metastatic pancreatic carcinoma, received weekly administration of cisplatin 40 mg m−2, 5-fluorouracil 500 mg m−2, epidoxorubicin 35 mg m−2, 6S stereoisomer of leucovorin 250 mg m−2 and glutathione 1.5 mg m−2, supported by a daily administration of lenograstim at a dose of 5 μg kg−1. Nineteen patients were men and three were women. Median age was 63 years (range 47–70). At study entry, pain was present in 15 out of 22 patients (68%) with a mean value of Scott–Huskisson scale of 27.6 ± 23.8, whereas a weight loss >10% was present in 15 patients. After eight weekly treatments, three partial responses were achieved for a response rate of 13% (95% CI 0–26%), five patients had stable disease and 14 progressed on therapy. Pain was present in 9 out of 22 patients (40%) with a mean value of Scott–Huskisson scale of 12.3 ± 18.4. Eight patients (36%) (three partial response and five stable disease) had a positive weight change. Toxicity was mild: WHO grade III or IV toxicity was recorded in terms of anaemia in 7 out of 188 cycles (3.7%), of neutropenia in 9 out of 188 cycles (4.7%) and of thrombocytopenia in 3 out of 188 cycles (1.5%). Median survival of all patients was 6 months. The outcome of this intensive chemotherapy regimen does not support its use in pancreatic cancer. © 1999 Cancer Research Campaig