Knockout of hyaluronidase Spam1 reduces age-related bone and cartilage changes in mouse knee.

OBJECTIVE: To investigate the role of Spam1 hyaluronidase in age-related bone and cartilage changes in the mouse knee. DESIGN: Spam1-/- and WT mice were euthanised at different ages from 10 to 52 weeks. The right hindlimbs were dissected, scanned with peripheral Quantitative Computed Tomography (pQCT) and then decalcified for histological analysis (modified Mankin score). In other mice, cartilages of both tibiae were sampled at 10, 30 and 52 weeks of age for RNA extraction and qPCR analysis. We assessed the expression of hyaluronidases Hyal1 and Hyal2, hyaluronan synthase HAS2, extracellular matrix proteases Mmp13 and Adamts-5, and type 2 collagen. RESULTS: Spam1-/- mice did not exhibit specific morphological characters up to 52 weeks of age. From 20 weeks, the proximal tibia of Spam1-/- mice had a significantly lower bone mineral density than WT mice. At 52 weeks, the modified Mankin score was significantly lower in Spam1-/- than WT mice. Spam1-/- chondrocytes expressed significantly less Hyal2 than WT ones at all ages and less Mmp13 at 52 weeks. Through all the experiment, the Hyal1 expression of Spam1-/- chondrocytes remained similar as that of WT chondrocytes. CONCLUSION: Spam1 knockout reduced significantly cartilage degradation in mouse knee whereas the chondrocyte expression of Hyal 1, Hyal 2 and Mmp13 was modified, suggesting a role of this hyaluronidase in cartilage metabolism.

Sensitivity of coccolithophores to carbonate chemistry and ocean acidification.

About one-third of the carbon dioxide (CO(2)) released into the atmosphere as a result of human activity has been absorbed by the oceans, where it partitions into the constituent ions of carbonic acid. This leads to ocean acidification, one of the major threats to marine ecosystems and particularly to calcifying organisms such as corals, foraminifera and coccolithophores. Coccolithophores are abundant phytoplankton that are responsible for a large part of modern oceanic carbonate production. Culture experiments investigating the physiological response of coccolithophore calcification to increased CO(2) have yielded contradictory results between and even within species. Here we quantified the calcite mass of dominant coccolithophores in the present ocean and over the past forty thousand years, and found a marked pattern of decreasing calcification with increasing partial pressure of CO(2) and concomitant decreasing concentrations of CO(3)(2-). Our analyses revealed that differentially calcified species and morphotypes are distributed in the ocean according to carbonate chemistry. A substantial impact on the marine carbon cycle might be expected upon extrapolation of this correlation to predicted ocean acidification in the future. However, our discovery of a heavily calcified Emiliania huxleyi morphotype in modern waters with low pH highlights the complexity of assemblage-level responses to environmental forcing factors.

[Earthquakes in El Salvador]. / Terremotos en El Salvador.

The Pan American Health Organization (PAHO) has 25 years of experience dealing with major natural disasters. This piece provides a preliminary review of the events taking place in the weeks following the major earthquakes in El Salvador on 13 January and 13 February 2001. It also describes the lessons that have been learned over the last 25 years and the impact that the El Salvador earthquakes and other disasters have had on the health of the affected populations. Topics covered include mass-casualties management, communicable diseases, water supply, managing donations and international assistance, damages to the health-facilities infrastructure, mental health, and PAHO's role in disasters.

Direct observation of the oceanic CO2 increase revisited.

We show, from recent data obtained at specimen North Pacific stations, that the fossil fuel CO2 signal is strongly present in the upper 400 m, and that we may consider areal extrapolations from geochemical surveys to determine the magnitude of ocean fossil fuel CO2 uptake. The debate surrounding this topic is illustrated by contrasting reports which suggest, based upon atmospheric observations and models, that the oceanic CO2 sink is small at these latitudes; or that the oceanic CO2 sink, based upon oceanic data and models, is large. The difference between these two estimates is at least a factor of two. There are contradictions arising from estimates based on surface partial pressures of CO2 alone, where the signal sought is small compared with regional and seasonal variability; and estimates of the accumulated subsurface burden, which correlates well other oceanic tracers. Ocean surface waters today contain about 45 micromol.kg-1 excess CO2 compared with those of the preindustrial era, and the signal is rising rapidly. What limits should we place on such calculations? The answer lies in the scientific questions to be asked. Recovery of the fossil fuel CO2 contamination signal from analysis of ocean water masses is robust enough to permit reasonable budget estimates. However, because we do not have sufficient data from the preindustrial ocean, the estimation of the required Redfield oxidation ratio in the upper several hundred meters is already blurred by the very fossil fuel CO2 signal we seek to resolve.

SUMA (Supply Management Project), a management tool for post-disaster relief supplies.

Frequently in the wake of disasters, large amounts of humanitarian supplies arrive from multiple sources within the country or from abroad. Only a portion of these donations actually responds to specific requests from the affected country. A significant part consists of unsolicited donations whose value--in terms of meeting immediate, life-threatening needs--is questioned by many disaster managers. In 1990, WHO initiated a supply management project, known as "SUMA", to provide national authorities with a management tool and the skills to sort and inventory large amounts of relief supplies in a short period of time. It is a technical cooperation programme to assist the local coordinating agency to get an accurate picture of what is potentially available in the affected area, and to sort the most valuable relief items from those of doubtful usefulness. National authorities have developed their SUMA teams in many situations, both in Latin America and the Caribbean; this article describes three of these experiences. A flood in Costa Rica, in 1995, where the Red Cross assumed national responsibility for managing relief supplies donated locally. The earthquake in Paéz, Colombia, also in 1995, where the National Disaster Committee activated SUMA for all supplies sent to the disaster area, with the exception of specialized health shipments channelled through the Ministry of Health. In Haiti, in 1994, a complex disaster was compounded by a tropical storm. All civilian supplies arriving at the airport were processed by the SUMA team which included customs officers among its members. The traditional problem of unsorted and inappropriate supplies, noted in most international disasters, seems to have been negligible, a trend which can perhaps be credited to 20 years of preparedness activities in Latin America and the Caribbean. The superficial analysis of the data underlines the potential for operational research on the standardized databases generated by SUMA.

Disaster preparedness: institutional capacity building in the Americas.

Latin American and Caribbean countries are prone to natural, technological and "complex" disasters. This vulnerability to catastrophic events led the region to undertake the long journey away from an ad hoc response towards institutional preparedness and, more recently, to disaster prevention and mitigation. This article attempts to outline the definitions and basic principles of institutional emergency preparedness, including reliance on the more effective use of existing resources, rather than establishment of special stockpiles and equipment; the critical importance of general participation and awareness; and the interrelationship of the health sector with others and the potential for leadership. How to assess the level of preparedness is discussed. Stress is placed on the fact that preparedness is traditionally confused with the existence of a written disaster plan. Preparedness should be seen as a never-ending, complex process that can only be assessed through an in-depth review of coordination, planning, training and logistic elements. There is also a fundamental distinction between preparedness, i.e., "getting ready to respond" and disaster prevention/mitigation, which aims to reduce the health impact. The latter calls for the collaboration of engineers, architects, planners and economists with the health sector. It is illustrated by the regional initiative in the Americas to reduce the physical vulnerability of hospitals to earthquakes and hurricanes. In spite of the encouraging achievements, much remains to be done. Weak areas include preparedness for technological disasters, and a true inter-country preventive approach to common disasters across borders. Electronic communications through the Internet will also help to suppress borders and boundaries, contributing to a truly collective approach to emergency preparedness and disaster relief coordination.

Carbon Dioxide Transport by Ocean Currents at 25{degrees}N Latitude in the Atlantic Ocean.

Measured concentrations of CO(2), O(2), and related chemical species in a section across the Florida Straits and in the open Atlantic Ocean at approximately 25 degrees N, have been combined with estimates of oceanic mass transport to estimate both the gross transport of CO(2) by the ocean at this latitude and the net CO(2) flux from exchange with the atmosphere. The northward flux was 63.9 x 10(6) moles per second(mol/s); the southward flux was 64.6 x 10(6) mol/s. These values yield a net CO(2) flux of 0.7 x 10(6) mol/s (0.26 +/- 0.03 gigaton of C per year) southward. The North Atlantic Ocean has been considered to be a strong sink for atmospheric CO(2), yet these results show that the net flux in 1988 across 25 degrees N was small. For O(2) the equivalent signal is 4.89 x 10(6) mol/s northward and 6.97 x 10(6) mol/s southward, and the net transport is 2.08 x 10(6) mol/s or three times the net CO(2) flux. These data suggest that the North Atlantic Ocean is today a relatively small sink for atmospheric CO(2), in spite of its large heat loss, but a larger sink for O(2) because of the additive effects of chemical and thermal pumping on the CO(2) cycle but their near equal and opposite effects on the CO(2) cycle.