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A new animal study from Europe has drawn an association between pregnant mothers’ sodium（钠） intake and their newborn’s kidney development. Among the most significant aspects of the study’s findings is that either too much or too little salt during pregnancy had an adverse effect on the prenatal development of the offspring’s kidneys. The consequence of such disruption can lead to high blood pressure in later years. These are the conclusions reached in the study, “Both High and Low Maternal Salt Intake in Pregnancy Alters Kidney Development in the Offspring,” conducted by Nadezda Koleganova, Grzegorz Piecha, Annett Müller, Monika Weckbach, Peter Schirmacher, and Marie-Luise Gross-Weissmann, Eberhard Ritz and Luis Eduardo Becker, all with the University of Heidelberg in Heidelberg, DE; and Jens Randel Nyengaard of the University of Aarhus, Aarhus, DK. Their study is published in the online edition of the American Journal of Physiology–Renal Physiology.BackgroundThis research builds upon past studies that recognize that excessive salt intake causes secretion（分泌） of endogenous（内生的） cardiotonic（强心剂） steroids such as marinobufagenin (MBG). For the pregnant female, this can be harmful since high concentrations of MBG are correlated to low birth-weight and higher blood pressure in the offspring.Previous research has also linked high blood pressure with a low nephron（肾元） number, critical because the nephron is the basic structural and functional unit of the kidney. The nephron eliminates wastes from the body, regulates blood volume and blood pressure, controls levels of electrolytes and metabolites, and regulates blood pH. Its functions are vital to life and are regulated by the endocrine system.MethodologySprague-Dawley rats were fed low, intermediate or high sodium diets during pregnancy and lactation. The litters were standardized to identical size at birth with 1:1 male to female ratio. The offspring were separated from their mothers at four weeks of age and subsequently received the intermediate sodium diet. The animals had free access to water and food and their body weight, food and water consumption were monitored weekly.The kidney structure was assessed at postnatal weeks 1 and 12, and the expression of proteins known to be involved in kidney development were examined at birth and 1 week of age. Blood pressure was measured by telemetry（远测手艺） in male offspring between the ages of two and nine months.ResultsThe researchers found that the number of glomeruli (the main structural unit of the kidney) during weeks 1-12 were significantly lower, and the measured blood pressure for males after the fifth month was higher in offspring of mothers on high- or low- compared with intermediate-sodium diet. High salt diet was paralleled（并行的） by higher concentrations of marinobufagenin in the amniotic fluid（羊水） and an increase in the expression of both GDNF and its inhibitor, sprouty-1 in the offspring’s kidney. The expression of FGF-10, a genetic signal responsible for kidney development, was lower in offspring of mothers on low-sodium diet and the expression of Pax-2 and FGF-2, tissue-specific genes that determine cell lineages, tissue patterning, and cellular proliferation was lower in offspring of mothers on high-sodium diet.

Life expectancy in Europe keeps increasing despite the obesity epidemic, with people in Britain reaching an older age than those living in the US, according to an analysis of trends over the last 40 years. These striking findings counteract（抵消，中和） concerns that the rising life expectancy trend in high income countries may be coming to an end in the face of health problems arising from obesity. Epidemiologist and population health expert Professor David Leon, of the London School of Hygiene & Tropical Medicine, points out that in the last five years most European countries have been going in a positive direction for the first time in decades – although the gap between East and West remains entrenched（根深蒂固的） .In an editorial published in the International Journal of Epidemiology, Professor Leon writes: “Despite what many may have assumed, and without being complacent（骄傲的） , current trends in European life expectancy are in a positive direction.”But while the European experience since 1980 underlines the centrality（中间，中心） of the social, political and economic determinants of health, many intriguing（有趣的） and important questions remain unanswered about the drivers of these extraordinary trends.”Along with other Western European countries, life expectancy has been rising steadily in the UK. An important contributor to this has been the decline in deaths from cardiovascular disease.According to Prof Leon, deaths from cardiovascular disease in the UK have seen “some of the largest and most rapid falls of any Western European country, partly due to improvements in treatment as well as reductions in smoking and other risk factors”.Despite spending more per capita on health care than any other country in the world, the US is at the same level as the lowest of any Western European country (Portugal for males and Denmark for females), while the rate for women is increasing at a much slower pace than Western Europe.In 2007, life expectancy in the US was 78 years compared to 80 in the UK.”This simple observation once again underlines that GDP and health care expenditure per capita are not good predictors of population health within high income countries,” Prof Leon writes.Within Europe, Prof Leon paints a startling contrast between East and West as the former Communist bloc struggles to catch up with its longer-living neighbours.

Using a bone-creating protein to augment（增加） the maxillary sinus（上颌骨窦） could improve dental implant success, according to Georgia Health Sciences University researchers. Dental implants, screws that anchor permanent prosthetic（假体的） teeth, won’t work if the bone in which they are anchored is too thin. Bone-thinning is a common cause and consequence following tooth loss. The current favored solution is to supplement the area with bone grafts to stabilize the implant base. But that technique is problematic “primarily because it involves additional surgeries to harvest the bone,” said Dr. Ulf M.E. Wikesjö, Interim Associate Dean for Research and Enterprise in the GHSU College of Dental Medicine.In animal studies, he and his team at the GHSU Laboratory for Applied Periodontal & Craniofacial Regeneration found that implanting bone morphogenetic（形态产生的） protein in the sinus more new bone will form within four weeks than using conventional bone grafting at the same site.”We found that BMP induced superior bone quality over that following bone grafts, which improves the chances for successful implants,” Wikesjö said. “BMP is phenomenal, because it’s a true, off-the-shelf product with ease of use that can produce real results, and it could be the new gold standard for this procedure.”According to the American Association of Oral and Maxillofacial Surgeons, 69 percent of adults ages 35-44 have lost at least one tooth due to decay, disease or trauma（创伤） , and 26 percent of adults have lost all permanent teeth by age 74. Before dental implants were available, the only options for replacing these missing teeth were dentures（假牙） and dental bridges, both of which could lead to further bone loss. Implants provide patients with numerous benefits, including improved oral health, appearance, speech, convenience, durability and ability to eat.

A lack of vitamin D, even in generally healthy people, is linked with stiffer arteries and an inability of blood vessels to relax, research from the Emory/Georgia Tech Predictive Health Institute has found. The results add to evidence that lack of vitamin D can lead to impaired vascular（血管的） health, contributing to high blood pressure and the risk of cardiovascular disease. Study participants who increased their vitamin D levels were able to improve vascular health and lower their blood pressure.The data is being presented on Sunday by Ibhar Al Mheid, MD, a cardiovascular researcher at Emory University School of Medicine, at the annual American College of Cardiology meeting in New Orleans. Al Mheid is one of five finalists for the ACC’s Young Investigators Award competition in physiology, pharmacology and pathology. He is working with Arshed Quyyumi, MD, professor of medicine and director of the Emory Cardiovascular Research Institute.The 554 participants in the study were Emory or Georgia Tech employees –average age 47 and generally healthy — who are taking part in the Center for Health Discovery and Well Being, part of the Emory/Georgia Tech Predictive Health Institute.The average level of 25-hydroxyvitamin D (a stable form of the vitamin reflecting diet as well as production in the skin) in participants’ blood was 31.8 nanograms per milliliter. In this group, 14 percent had 25-hydroxyvitamin D levels considered deficient, or less than 20 nanograms per milliliter, and 33 percent had levels considered insufficient, less than 30 nanograms per milliliter.The researchers monitored the ability of participants’ blood vessels to relax by inflating and then removing a blood pressure cuff on their arms. To allow blood to flow back into the arm, blood vessels must relax and enlarge – a change that can be measured by ultrasound. The researchers also made other measurements of smaller blood vessels and examined the resistance to blood flow imposed by the arteries.Even after controlling for factors such as age, weight and cholesterol, people with lower vitamin D levels still had stiffer arteries and impaired vascular function, Al Mheid says.”We found that people with vitamin D deficiency had vascular dysfunction comparable to those with diabetes or hypertension,” he says.Throughout the body, a layer of endothelial cells（内皮细胞） lines the blood vessels, controlling whether the blood vessels constrict or relax and helping to prevent clots（血块） that lead to strokes and heart attacks.”There is already a lot known about how vitamin D could be acting here,” Al Mheid says. “It could be strengthening endothelial cells and the muscles surrounding the blood vessels. It could also be reducing the level of angiotensin, a hormone that drives increased blood pressure, or regulating inflammation.”

Using eyes made of a calcium carbonate（碳酸钙） crystal, a simple mollusk（软体动物） may have evolved enough vision to spot potential predators, scientists say. The three-inch-long mollusks, called chitons（石鳖） , have hundreds of eye-like structures with lenses made of aragonite, a type of rock. It’s the first time scientists have found an animal that makes eye lenses from aragonite and not the rock’s close cousin, calcite.”It’s surprising how these creatures make their eyes from rocks,” said Duke biologist Sönke Johnsen. Most animals make their eyes from cells with proteins and chitin. “But it seems like an easy way to evolve eyes by using what you’ve already got,” he said. Chitons also make their shells from aragonite.Johnsen and former Duke Ph.D. student Daniel Speiser studied West Indian fuzzy chitons, or Acanthopleura granulata, which have flat shells made of eight separate plates. Hundreds of tiny lenses on the surface of the plates cover clusters of light-sensitive cells beneath.Scientists discovered the eyes decades ago. But it wasn’t clear whether chitons used these eyes to see objects overhead or simply to sense changes in light. “Turns out they can see objects, though probably not well,” said Speiser, who recently became a post-doctoral fellow at the University of California, Santa Barbara. The results of the new chiton study appear in the April 26 Current Biology.To test the creature’s vision, Speiser placed individual chitons on a slate slab（厚板） . When left undisturbed, they would lift part of their armored, oval-shaped body to breathe. At this point, Speiser would show them either a black disk ranging from 0.35 centimeters to 10 centimeters in diameter or a corresponding gray slide that blocked the same amount of light. The disk or slide appeared 20 centimeters above the chitons.When shown the gray screens, the chitons did not respond. But they clamped down when shown a black disk 3 centimeters or larger in diameter. That would be the equivalent of humans looking in the sky and seeing a disk the diameter of 20 moons, making human vision about a thousand times sharper than chiton vision, Johnsen said.Because the chitons responded to the larger disks and not the gray slides, they seem to be seeing the disk and not simply responding to a change in light, said University of Sussex biologist Michael Land, an expert on animal vision who was not involved in the research. But it’s not yet clear if they respond only to the removal of light by the disk as opposed to added light.Land also said it’s not likely that the chitons’ eyes were part of the evolutionary route to human eyes.Chitons are ancient, primitive species that first appeared on Earth more than 500 million years ago. But the oldest chitons with eyes only began to appear in the fossil record in the last 25 million years, making their eyes among the most recent to evolve in animals. Speiser said chitons probably evolved to have eyes with lenses so they could see their predators and defend against being eaten.Speiser and his colleagues also tested whether the chitons’ eyes work in both air and water, since some species spend time in both. The experiments made a strong case for the chiton lens being able to focus light differently depending on whether the animal is above or below water, Land said.He added that chiton eyes are still an anomaly（异常，不法则） in the evolution of vision. The retinas are structurally similar to snail and slug（鼻涕虫） retinas. But snail and slug retinas respond to the appearance of light, while chiton retinas may only respond to the removal of light, a difference that might be worth another look, Land said.

Bremerhaven/Geesthacht/Potsdam, 14 April 2011. The coastline in Arctic regions reacts to climate change with increased erosion and retreats by half a metre per year on average. This means substantial changes for Arctic ecosystems near the coast and the population living there. A consortium（财团，结合） of more than thirty scientists from ten countries, including researchers from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association and from the Helmholtz Centre in Geesthacht, comes to this conclusion in two studies published in Estuaries and Coasts and online on www.arcticcoasts.org. They jointly investigated over 100,000 kilometres and thus a fourth of all Arctic coasts and their results have now been published for the first time. The changes are particularly dramatic in the Laptev, East Siberian and Beaufort Seas, where coastal erosion rates reach more than 8 metres a year in some cases. Since around a third of the world’s coasts are located in the Arctic permafrost（永久冻土） , coastal erosion may affect enormous areas in future. In general Arctic coasts react more sensitively to global warming than coasts in the mid-latitudes. Up to now they have been protected against the eroding force of the waves by large sea ice areas. Due to the continuous decline in sea ice, this protection is jeopardised and we have to reckon with rapid changes in a situation that has remained stable for millennia.Two thirds of the Arctic coasts do not consist of rock, but of frozen soft substrate (permafrost). And precisely these coasts are extremely hard hit by erosion. As a rule, Arctic regions are quite thinly populated. However, as nearly everywhere in the world, the coasts in the far north are important axes for economic and social life. The growing need for global energy resources as well as increasing tourism and freight（货运，运费） transport additionally intensify anthropogenic（报酬的） influence on the coastal regions of the Arctic. For wild animal stocks, like the great caribou（北美驯鹿） herds of the north, and the widespread freshwater lakes near the coast progressive erosion brings about significant changes in ecological conditions.

Brazilians are world leaders in using biofuels for gasoline（汽油） . About a quarter of their automobile fuel consumption comes from sugarcane, which significantly reduces carbon dioxide emissions that otherwise would be emitted from using gasoline. Now scientists from the Carnegie Institution’s Department of Global Ecology have found that sugarcane has a double benefit. Expansion of the crop in areas previously occupied by other Brazilian crops cools the local climate. It does so by reflecting sunlight back into space and by lowering the temperature of the surrounding air as the plants “exhale（呼气） ” cooler water. The study is published in the 2nd issue of Nature Climate Change, posted on-line April 17. The research team, led by Carnegie’s Scott Loarie, is the first to quantify the direct effects on the climate from sugarcane expansion in areas of existing crop and pastureland of the cerrado, in central Brazil.The researchers used data from hundreds of satellite images over 733,000 square miles— an area larger than the state of Alaska. They measured temperature, reflectivity (also called albedo), and evapotranspiration— the water loss from the soil and from plants as they exhale water vapor.As Loarie explained: “We found that shifting from natural vegetation to crops or pasture results in local warming because the plants give off less beneficial water. But the bamboo-like sugarcane is more reflective and gives off more water— much like the natural vegetation. It’s a potential win-win for the climate— using sugarcane to power vehicles reduces carbon emissions, while growing it lowers the local air temperature.”The scientists found that converting from natural vegetation to crop/pasture on average warmed the cerrado by 2.79 °F (1.55 °C), but that subsequent conversion to sugarcane, on average, cooled the surrounding air by 1.67 °F (0.93°C).The researchers emphasize that the beneficial effects are contingent（因环境而异的） on the fact sugarcane is grown on areas previously occupied by crops or pastureland, and not in areas converted from natural vegetation. It is also important that other crops and pastureland do not move to natural vegetation areas, which would contribute to deforestation.So far most of the thinking about ecosystem effects on climate considers only impacts from greenhouse gas emissions. But according to coauthor Greg Asner, “It’s becoming increasingly clear that direct climate effects on local climate from land-use decisions constitute significant impacts that need to be considered core elements of human-caused climate change.”

Could veterans of war, rape victims and other people who have seen horrific crimes someday have the traumatic memories that haunt them weakened in their brains? In a new study, UCLA life scientists report a discovery that may make the reduction of such memories a reality. “I think we will be able to alter memories someday to reduce the trauma from our brains,” said the study’s senior author, David Glanzman, a UCLA professor of integrative biology and physiology and of neurobiology（神经生物学） .The study appears in the April 27 issue of the Journal of Neuroscience, a premier neuroscience journal.Glanzman, a cellular neuroscientist, and his colleagues report that they have eliminated, or at least substantially weakened, a long-term memory in both the marine snail known as Aplysia and neurons in a Petri dish. The researchers say they gaining important insights into the cell biology of long-term memory.They discovered that the long-term memory for sensitization in the marine snail can be erased by inhibiting the activity of a specific protein kinase — a class of molecules that modifies proteins by chemically adding to them a phosphate (an inorganic chemical), which changes the proteins’ structure and activity. The protein kinase is called PKM (protein kinase M), a member of the class known as protein kinase C (PKC), which is associated with memory.The research has important potential implications for the treatment of post-traumatic stress disorder, as well as drug addiction, in which memory plays an important role, and perhaps Alzheimer’s disease and other long-term memory disorders.”Almost all the processes that are involved in memory in the snail also have been shown to be involved in memory in the brains of mammals,” said Glanzman, who added that the human brain is far too complicated to study directly.PKM is rare in that while most protein kinases（蛋白激酶） have both a catalytic domain, which is the part of the molecule that does its work, and a regulatory domain, akin to an on–off switch that can be used by other signaling pathways to shut off the activity of the kinase, PKM has only the catalytic domain — not the regulatory domain.”This means that once PKM is formed, there is no way to shut it off,” said Glanzman, who is a member of UCLA’s Brain Research Institute. “Once it is activated, PKM’s continual activity maintains a memory until PKM degrades.”Glanzman decided to study PKM in the marine snail, which has simple forms of learning and a simple nervous system, so that he could understand in precise detail how PKM’s activity maintains a long-term memory, a process that is not well understood.Glanzman and his colleagues — researchers Diancai Cai, lead author of the study; Kaycey Pearce; and Shanping Chen, all of whom work in his laboratory — studied a simple kind of memory called sensitization. If marine snails are attacked by a predator, the attack heightens their sensitivity to environmental stimuli — a “fundamental form of learning that is necessary for survival and is very robust in the marine snail,” Glanzman said.

Active efforts are required to preserve biodiversity in the seas – that far most people are in agreement. But in our enthusiasm to save uncommon species, we sometimes miss the common species that form the basis（根本，底部） of marine ecosystems. ‘Change strategy’ is the challenge to the authorities from researchers at the University of Gothenburg, Sweden. An inconceivably（不成思议地） large proportion of the animals that live in the seas are so uncommon that it is difficult to find more than a few specimens. Committing most resources to saving individual species is not just an expensive business – it would also risk destroying the foundation for ecosystems, the research of Professor Kerstin Johannesson shows.Her research team is able to demonstrate that it is the common species that are of really great significance for ecosystems, by establishing habitats for other species. It is therefore in all probability the most common species that determine the future of all species. If the common species disappear, it will have great consequences.An alarming example of what can happen is that the cod populations in the fjords（海湾，峡湾） of the Bohuslän coast have almost without exception disappeared. These fjords have consequently lost one of their most important species. It can have far-reaching consequences for several other species when the environments of the shallow bays change.”Without the big predatory fish, the sea-grass meadows become clogged, with the result that the shallow bays no longer act as larders and nurseries for inshore（近海岸的） fish. While life slowly dies out, the blame is put on eutrophication.”Kerstin Johannesson’s research is concerned with how different populations within one species may be so genetically different that they actually do not have very much to do with each other, and that in particular they are not interchangeable. If a local population disappears, it will not automatically be replaced by individuals from another population migrating in. In the worst case, even individuals of the other population are unable to cope in the environment of the extinct population.”That’s how it is with the cod populations in Bohuslän. Despite tough restrictions on catches and despite North Sea cod visiting the Bohuslän fjords every year, we are not getting the cod populations back. A similar example is the cod off the coast of Newfoundland in Canada, which have not returned despite a complete halt to fishing for nearly 20 years.”Focusing on the species in order to preserve species diversity in the seas is therefore an incorrect approach that may instead lead to greater losses. Despite this, there is a lack of legislation and recommendations today on how genetic variation within species should to be managed.