BIOCHEMISTRY - KSRCAS

Antibiotic-resistance making kidney infections more deadly

Medication-resistant bacteria are making it more difficult to treat a common but severe kidney infection, says a study. Pyelonephritis, infection of the kidney usually caused by E. coli bacteria and which can start as a urinary tract infection, causes fever, back pain and vomiting. About half of people infected require hospitalisation. If not treated with effective antibiotics, it can cause sepsis and death. "This is a very real example of the threat posed by the emergence of new antibiotic-resistant strains of bacteria, which greatly complicates treatment of infection," said the study's lead author David Talan, Professor at David Geffen School of Medicine at University of California, Los Angeles. In an earlier study based on data from 10 large hospital emergency departments in the US, almost 12 per cent of people diagnosed with pyelonephritis had infections resistant to the standard class of antibiotic used in treatment, fluoroquinolone. That is up from four per cent in a similar study conducted a decade ago. The new study, published in the jurnal Emerging Infectious Diseases, also documents the emergence of infections caused by a specific strain of E. coli that is resistant to additional types of antibiotics, severely limiting treatment options. That strain, dubbed ESBL for the antibiotic-destroying enzymes it produces (extended-spectrum beta-lactamases), was not detected in the previous study. Currently, there are only a few intravenous antibiotic options to treat ESBL-related infections, and no oral antibiotics that are consistently effective. The study included 453 people diagnosed with kidney infection. The study participants were diagnosed between July 2013 and December 2014 in 10 emergency departments’ at large hospitals in the US.
The rates of ESBL-related infections varied from zero per cent to more than 20 per cent, depending on the location of the emergency room and patient risk factors. About three of every four people infected with ESBL-producing E. coli were initially treated with antibiotics ineffective against that particular strain of bacteria, placing them at risk for poor outcomes, the researchers reported.

New material to make computers 100 times more power efficient

Researchers including one of Indian-origin have engineered a material that could lead to a new generation of computing devices, packing in more computing power while consuming nearly 100 times less energy thant today's electronics require. "Electronics are the fastest-growing consumer of energy worldwide," said one of the study authors, Ramamoorthy Ramesh from Lawrence Berkeley National Laboratory in the US. "Today, about five per cent of our total global energy consumption is spent on electronics, and that's projected to grow to 40-50 percent by 2030 if we continue at the current pace and if there are no major advances in the field that lead to lower energy consumption," Ramesh said.
Known as a magnetoelectric multiferroic material, it combines electrical and magnetic properties at room temperature and relies on a phenomenon called "planar rumpling." The new material sandwiches together individual layers of atoms, producing a thin film with magnetic polarity that can be flipped from positive to negative or vice versa with small pulses of electricity. In the future, device-makers could use this property to store the binary digits that underpin computing devices. "Before this work, there was only one other room-temperature multiferroic whose magnetic properties could be controlled by electricity," said John Heron, Assistant Professor at University of Michigan who worked on the material with researchers at Cornell University. "That electrical control is what excites electronics makers, so this is a huge step forward," Heron noted. Room-temperature multiferroics are a hotly pursued goal in the electronics field because they require much less power to read and write data than today's semiconductor-based devices. In addition, their data doesn't vanish when the power is shut off. Those properties could enable devices that require only brief pulses of electricity instead of the constant stream that's needed for current electronics, using an estimated 100 times less energy.

Maximum human lifespan has already been reached

Since the 19th century, average life expectancy has risen almost continuously thanks to improvements in public health, diet, the environment and other areas. On average, for example, U.S. babies born today can expect to live nearly until age 79 compared with an average life expectancy of only 47 for Americans born in 1900. Since the 1970s, the maximum duration of life -- the age to which the oldest people live -- has also risen. But according to the Einstein researchers, this upward arc for maximal lifespan has a ceiling -- and we've already touched it. "Demographers as well as biologists have contended there is no reason to think that the ongoing increase in maximum lifespan will end soon," said senior author Jan Vijg, Ph.D., professor and chair of genetics, the Lola and Saul Kramer Chair in Molecular Genetics, and professor of ophthalmology & visual sciences at Einstein. "But our data strongly suggest that it has already been attained and that this happened in the 1990s."

Dr. Vijg and his colleagues analyzed data from the Human Mortality Database, which compiles mortality and population data from more than 40 countries. Since 1900, those countries generally show a decline in late-life mortality: The fraction of each birth cohort (i.e., people born in a particular year) who survive to old age (defined as 70 and up) increased with their calendar year of birth, pointing toward a continuing increase in average life expectancy. But when the researchers looked at survival improvements since 1900 for people aged 100 and above, they found that gains in survival peaked at around 100 and then declined rapidly, regardless of the year people were born. "This finding indicates diminishing gains in reducing late-life mortality and a possible limit to human lifespan," said Dr. Vijg. He and his colleagues then looked at "maximum reported age at death" data from the International Database on Longevity. They focused on people verified as living to age 110 or older between 1968 and 2006 in the four countries (the U.S., France, Japan and the U.K.) with the largest number of long-lived individuals. Age at death for these supercentenarians increased rapidly between the 1970s and early 1990s but reached a plateau around 1995 -- further evidence for a lifespan limit. This plateau, the researchers note, occurred close to 1997 -- the year of death of 122-year-old French woman Jeanne Calment, who achieved the maximum documented lifespan of any person in history.

Using maximum-reported-age-at-death data, the Einstein researchers put the average maximum human life span at 115 years -- a calculation allowing for record-oldest individuals occasionally living longer or shorter than 115 years. (Jeanne Calment, they concluded, was a statistical outlier.) Finally, the researchers calculated 125 years as the absolute limit of human lifespan. Expressed another way, this means that the probability in a given year of seeing one person live to 125 anywhere in the world is less than 1 in 10,000. "Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan," said Dr. Vijg. "While it's conceivable that therapeutic breakthroughs might extend human longevity beyond the limits we've calculated, such advances would need to overwhelm the many genetic variants that appear to collectively determine the human lifespan. Perhaps resources now being spent to increase lifespan should instead go to lengthening healthspan -- the duration of old age spent in good health." 

By
Chandrasekaran
III B.Sc., 

Department of Biochemistry