First detection of pregnancy protein in older people destined for Alzheimer's disease

 

In an advance toward a much-needed early diagnostic test for Alzheimer's disease (AD), scientists have discovered that older women destined to develop AD have high blood levels of a protein linked to pregnancy years before showing symptoms. Their report appears in ACS' Journal of Proteome Research.

Theo Luider and colleagues explain that more than 26 million people worldwide already have AD, and the numbers are rising with the graying of the population. Doctors can prescribe any of several drugs to slow the disease's advance. But it is important to start treatment as early as possible. Unfortunately, however, no test exists to diagnose patients before obvious memory loss and other symptoms appear. Luider's team decided to look for proteins in the blood that might be used in such a test.

They looked for those proteins in blood samples of 86 people aged 60-90 who participated in a larger study of aged-related brain changes conducted in The Netherlands. Surprisingly, Luider's group found that significant elevations in pregnancy zone protein (PZP) occurred in women an average of 4 years before diagnosis of AD. Scientists long have known that PZP levels rise during pregnancy, but this was the first link with AD. Luider further discovered the apparent source of the PZP in the brain of these women, who were not pregnant: PZP was being produced in senile plaques, degenerated areas of the brain associated with AD.

More information: “Serum Levels of Pregnancy Zone Protein Are Elevated in Presymptomatic Alzheimer’s Disease” J. Proteome Res., Article ASAP. DOI: 10.1021/pr200270z

Abstract
We have sought for disease-related proteins that could predict the onset of Alzheimer’s disease (AD) in a study population derived from the Rotterdam Scan Study, a population-based prospective cohort study designed to investigate the etiology and natural history of age-related brain changes in the elderly. The serum proteome of 43 persons who developed AD, after an average of 4.2 years (±2.6 years SD) after blood sampling, and 43 gender- and age-matched controls who remained dementia-free during follow-up was investigated by liquid chromatography mass spectrometry. We identified 61 differentially expressed peptides between presymptomatic AD and controls, 9 of which were derived from pregnancy zone protein (PZP). Quantitative measurements using a multiple reaction monitoring assay showed a significant increase in concentration of PZP in presymptomatic AD (34.3 ± 20.6 mg/L) compared with controls (23.6 ± 13.6 mg/L) (p = 0.006). The difference in PZP was significant in women. Immunohistochemical validation of the findings on brain tissue sections showed strong PZP expression in senile plaques and in microglial and glial cells in AD with only low expression in some scattered glial cells in controls.

Provided by American Chemical Society (news : web)

'Plastic bottle' solution for arsenic-contaminated water threatening 100 million people

ScienceDaily (Sep. 1, 2011) — With almost 100 million people in developing countries exposed to dangerously high levels of arsenic in their drinking water, and unable to afford complex purification technology, scientists have now described a simple, inexpensive method for removing arsenic based on chopped up pieces of ordinary plastic beverage bottles coated with a nutrient found in many foods and dietary supplements.

The report was part of the 242nd National Meeting & Exposition of the American Chemical Society (ACS), a major scientific meeting with 7,500 technical papers, being held in Denver Colorado the week of August 29.

"Dealing with arsenic contamination of drinking water in the developing world requires simple technology based on locally available materials," said study leader Tsanangurayi Tongesayi, Ph.D., professor of analytical and environmental chemistry at Monmouth University, West Long Branch, N.J. "Our process uses pieces of plastic water, soda pop and other beverage bottles. Coat the pieces with cysteine -- that's an amino acid found in dietary supplements and foods -- and stir the plastic in arsenic-contaminated water. This works like a magnet. The cysteine binds up the arsenic. Remove the plastic and you have drinkable water."

Tongesayi described laboratory tests of the plastic bottle arsenic removal method on water containing 20 parts per billion (ppb) of arsenic, which is two times the safe standard set by the U.S. Environmental Protection Agency for drinking water. It produced drinkable water with 0.2 ppb of arsenic that more than meets the federal standard.

The technology is so straight-forward that people without technical skills can use it, Tongesayi said, citing that as one of its advantages over some of the existing arsenic-removal technologies. It can use discarded plastic bottles available locally, and the application of cysteine does not require complicated technology. Tongesayi is seeking funding or a commercial partner, which he said is the key to moving the arsenic-removing process into use in a relatively short time. The technology also has the potential for removing other potentially toxic heavy metals from drinking water.

Odorless, tasteless and colorless, arsenic enters drinking water supplies from natural deposits in soil and rock that occur in some parts of the world, including parts of the United States, and from agricultural and industrial sources. Symptoms of arsenic poisoning include thickening and discoloration of the skin; stomach pain, nausea, vomiting and diarrhea; vision loss; and numbness in hands and feet. Arsenic also has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver and prostate.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Chemical Society.

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Does selenium prevent cancer? It may depend on which form people take

Scientists are reporting that the controversy surrounding whether selenium can fight cancer in humans might come down to which form of the essential micronutrient people take. It turns out that not all "seleniums" are the same — the researchers found that one type of selenium supplement may produce a possible cancer-preventing substance more efficiently than another form of selenium in human cancer cells. Their study appears in the ACS' journal Biochemistry.

Hugh Harris and colleagues note that although the Nutritional Prevention of Cancer clinical trial showed that selenium reduced the risk of cancer, a later study called the Selenium and Vitamin E Cancer Prevention Trial did not show a benefit. A major difference between the trials was the form of selenium that was used. To find out whether different types of selenium have different chemopreventive properties, the researchers studied how two forms—SeMet and MeSeCys—are processed in human lung cancer cells.

The researchers found that MeSeCys killed more lung cancer cells than SeMet did. Also, lung cancer cells treated with MeSeCys processed the selenium differently than than cells treated with SeMet. They say that these findings could explain why studies on the health benefits of selenium sometimes have conflicting results.

Provided by American Chemical Society (news : web)