Mars and the ESA Science Programme - the case for Mars polar science.

Current plans within the European Space Agency (ESA) for the future investigation of Mars (after the ExoMars programme) are centred around participation in the Mars Sample Return (MSR) programme led by NASA. This programme is housed within the Human and Robotic Exploration (HRE) Directorate of ESA. This White Paper, in response to the Voyage 2050 call, focuses on the important scientific objectives for the investigation of Mars outside the present HRE planning. The achievement of these objectives by Science Directorate missions is entirely consistent with ESA's Science Programme. We illustrate this with a theme centred around the study of the Martian polar caps and the investigation of recent (Amazonian) climate change produced by known oscillations in Mars' orbital parameters. Deciphering the record of climate contained within the polar caps would allow us to learn about the climatic evolution of another planet over the past few to hundreds of millions of years, and also addresses the more general goal of investigating volatile-related dynamic processes in the Solar System.

The influence of the menstrual cycle, normal pregnancy and pre-eclampsia on platelet activation.

Platelet activation has a key role in mediating thrombotic and inflammatory events. This study aimed to determine the influence of the menstrual cycle, pregnancy and pre-eclampsia on in vivo platelet activation. Twelve healthy nulliparous, non-smoking women with regular menses were studied over a single menstrual cycle. Twenty-one healthy primigravida pregnant women were studied longitudinally at 16, 24, 32 and 37 weeks gestation and seven weeks post-partum. Sixteen primigravida women with pre-eclampsia were studied at time of diagnosis and at seven weeks post-partum. Platelet-monocyte aggregates and platelet-surface P-selectin expression were assessed by flow-cytometry. Soluble P-selectin and CD40 ligand (CD40L) were measured by ELISA. Markers of platelet activation did not vary over the menstrual cycle. Platelet-monocyte aggregates were greater in the third trimester of pregnancy compared to non-pregnant women (p=0.003). Platelet surface and plasma soluble P-selectin concentrations increased with gestation (p<0.0001) and were raised by 24 weeks of pregnancy compared to non-pregnant women (p< or =0.02 for both) and together with platelet monocyte aggregates, decreased post-partum (p< or =0.02). Soluble CD40L concentrations fell in pregnancy, reaching a nadir at mid-gestation (p=0.002). There were no differences in markers of platelet activation between normal and pre-eclamptic pregnancies. In conclusion, platelet activation is increased in pregnancy and increases with gestation but is unaffected by pre-eclampsia. This suggests that systemic platelet activation is a feature of pregnancy but this is not affected by established pre-eclampsia.

Influence of menstrual cycle on circulating endothelial progenitor cells.

BACKGROUND: Endothelial progenitor cells (EPCs) are circulating mononuclear cells that participate in angiogenesis. The aim of this study was to determine the influence of the menstrual cycle on the number and function of EPCs, and to investigate their relationship with circulating concentrations of sex steroids and inflammatory mediators. METHODS: Ten healthy nulliparous, premenopausal, non-smoking women with regular menses were studied over a single menstrual cycle. Venepuncture was performed in the menstrual, follicular, peri-ovulatory and luteal phases. EPCs were quantified by flow cytometry (CD133(+)CD34(+)KDR(+) phenotype) and the colony-forming unit (CFU-EPC) functional assay. Circulating concentrations of estradiol, progesterone and inflammatory mediators (TNF-alpha, IL-6, sICAM-1 and VEGF) were measured by immunoassays. RESULTS: The numbers of CD133(+)CD34(+)KDR(+) cells were higher in the follicular phase (0.99 +/- 0.3 x 10(6) cells/l) compared with the peri-ovulatory phase (0.29 +/- 0.1 x 10(6) cells/l; P < 0.05). In contrast, the numbers of CFU-EPCs did not vary over the menstrual cycle. There were no correlations between EPCs and concentrations of either circulating sex steroids or inflammatory mediators. CONCLUSIONS: CD133(+)CD34(+)KDR(+) cells but not CFU-EPCs vary during the menstrual cycle. Our findings suggest a potential role for circulating EPCs in the normal cycle of physiological angiogenesis and repair of the uterine endometrium that is independent of circulating sex steroids or inflammatory mediators.

Potassium depletion stimulates mRNA expression of proximal tubule AT1 angiotensin II receptors.

Dietary potassium (K+) deficiency is associated with blood pressure elevation and impaired urinary sodium excretion. Since angiotensin II is a potent stimulator of tubular sodium transport, we studied the effect of low [K+] on expression of kidney AT1 angiotensin receptors. In rabbits fed a K+-deficient diet for 14 days, plasma [K+] was significantly reduced compared to rabbits fed a standard diet (control: 4.06 +/- 0.12 vs. K+-deficient: 2.66 +/- 0.19 mmol/l; p < 0.001; n = 6-9). By Northern hybridization or RNase protection assays, dietary K+ deficiency caused an increase in mRNA expression for AT1 receptors in kidney cortex (43.5 +/- 12.9% increase vs. control; p < 0.04; n = 8), and in proximal tubule segments in suspension (76.4 +/- 28.8% increase vs. control; p < 0.005; n = 6). K+ deficiency had no effect on AT1 receptor mRNA expression in liver, or on mRNA expression of beta-actin in kidney cortex, proximal tubule suspensions, or liver. To determine if low extracellular [K+] might directly modulate AT1 receptor mRNA expression, primary cultures of rabbit proximal tubule cells were incubated for 1, 3, 6 or 24 h in media with or without 5 mmol/l K+. Incubation of cells in 0 mmol/l K+ caused a 99.2 +/- 32.9% increase in AT1 receptor mRNA expression at 3 h (p < 0.001; n = 14), returning to control levels by 24 h. Incubation of proximal tubule cells in 0 mmol/l K+ also caused a significant increase in basolateral membrane specific binding of [125I]-angiotensin II (p < 0.05; n = 4). These results indicate that dietary K+ deficiency and low extracellular [K+] stimulate expression of kidney AT1 angiotensin II receptors. Increased AT1 receptor mRNA and protein expression in proximal tubule may promote enhanced sodium reabsorption in K+ deficiency.

Bacteremia caused by Vibrio hollisae.

Vibrio hollisae was recovered from the bloodstream of a 36-year-old man with chronic active hepatitis who was admitted to the hospital with signs of gastrointestinal illness. V. hollisae is an infrequent human pathogen associated with seafood ingestion. No etiologic link to seafood was demonstrated in this case report.

The child abuse program in a child guidance center.

This paper is a case example of how one private child guidance clinic responded to problems of child abuse seen in the clinic and how the center moved from the "micro-level" of treating individual victims and their families to the "macro-level" of education and community involvement. The authors show how case-by-case treatment of abused families can be used as a guide for program development and community education.

Trans-uretero-ureterostomy: British experience.

158 replies to a questionnaire suggest that many British surgeons remain wary of using trans-uretero-ureterostomy, fearing to risk the opposite ureter and kidney or preferring to use a Boari flap or other operation. 141 (27 personal and 114 reported) cases are surveyed. 56 simple Y-anastomoses performed by 27 surgeons gave very good results, with only 4 exceptions due to wrong indications or techniques. Complications were rare. No damage to any opposite ureter or kidney by the procedure was reported. 10 operations enabling a solitary kidney to drain via the opposite spare ureter were all successful. We recommended that during nephrectomy any spare healthy ureter should be preserved so that, if necessary, it can be used to drain the opposite kidney.