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Dr. Marie Gabrielle Laguna

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Medical doctor-internist

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Forgetting can make you smarter

Aug 10, 2017

1649

For most people having a good memory means being able to remember more information clearly for long periods of time. For neuroscientists too, the inability to remember was long believed to represent a failure of the brain’s mechanisms for storing and retrieving information.

Paul Frankland, a senior fellow in CIFAR’s Child & Brain Development program, and Blake Richards, an associate fellow in the Learning in Machines & Brains program, say that our brains are actively working to forget. These researchers from University of Toronto propose that the goal of memory is not to transmit the most accurate information over time, but to guide and optimize intelligent decision making by only holding on to valuable information.

The review paper, published in the journal�Neuron, review literature on remembering, known as persistence, and the newer body of research on forgetting, or transience. The recent increase in research into the brain mechanisms that promote forgetting revealed that forgetting is just as important a component of our memory system as remembering.

One of these mechanisms is the weakening or elimination of synaptic connections between neurons in which memories are encoded. Another mechanism is the generation of new neurons from stem cells. As new neurons integrate into the hippocampus, the new connections remodel hippocampal circuits and overwrite memories stored in those circuits, making them harder to access. This may explain why children, whose hippocampi are producing more new neurons, forget so much information.

It may seem counterintuitive that the brain would expend so much energy creating new neurons at the detriment of memory. Richards, whose research applies artificial intelligence (AI) theories to understanding the brain, looked to principles of learning from AI for answers. Using these principles, the authors frame an argument that the interaction between remembering and forgetting in the human brain allows us to make more intelligent memory-based decisions.

Forgetting allows us to adapt to new situations by letting go of outdated and potentially misleading information that can no longer help us maneuver changing environments. And forgetting facilitates decision making by allowing us to generalize past events to new ones.

Genes influence most diseases, researchers report

Aug 9, 2017

2016

A core assumption in the study of disease-causing genes has been that they are clustered in molecular pathways directly connected to the disease. But work by a group of researchers at the Stanford University School of Medicine suggests otherwise

The gene activity of cells is so broadly networked that virtually any gene can influence disease, the researchers found. As a result, most of the heritability of diseases is due not to a handful of core genes, but to tiny contributions from vast numbers of peripheral genes that function outside disease pathways.

Any given trait, it seems, is not controlled by a small set of genes. Instead, nearly every gene in the genome influences everything about us. The effects may be tiny, but they add up.

Jonathan Pritchard, PhD, Professor of Genetics and Biology, is the senior author, and graduate student Evan Boyle and postdoctoral scholar Yang Li, PhD, share lead authorship. Their work is described in a paper published in�Cell.

The researchers call their provocative new understanding of disease genes an “omnigenic model” to indicate that almost any gene can influence diseases and other complex traits. In any cell, there might be 50 to 100 core genes with direct effects on a given trait, as well as easily another 10,000 peripheral genes that are expressed in the same cell with indirect effects on that trait, said Pritchard, who is also a Howard Hughes Medical Institute investigator.

Each of the peripheral genes has a small effect on the trait. But because those thousands of genes outnumber the core genes by orders of magnitude, most of the genetic variation related to diseases and other traits comes from the thousands of peripheral genes. So, ironically, the genes whose impact on disease is most indirect and small end up being responsible for most of the inheritance patterns of the disease.

Pritchard’s omnigenic model promises to take basic biology in new directions and means biologists need to think a lot more about the structure of networks that link together those thousands of peripheral disease genes.

Extra-virgin olive oil preserves memory, protects brain against Alzheimer’s

Aug 8, 2017

1758

�The Mediterranean diet, rich in plant-based foods, is associated with a variety of health benefits, including a lower�incidence of dementia. Now, researchers at the Lewis Katz School of Medicine at Temple University (LKSOM) have identified a specific ingredient that protects against cognitive decline: extra-virgin olive oil, a major component of the Mediterranean diet. In a study published online June 21 in the�Annals of Clinical and Translational Neurology, the researchers show that the consumption of extra-virgin olive oil protects memory and learning ability and reduces the formation of amyloid-beta plaques and neurofibrillary tangles in the brain — classic markers of Alzheimer’s disease.

The Temple team, headed by senior investigator Domenico Praticò, MD, Professor in the Departments of Pharmacology and Microbiology and the Center for Translational Medicine at LKSOM identified the mechanisms underlying the protective effects of extra-virgin olive oil. It reduces brain inflammation and activates a process known as autophagy.

“Brain cells from mice fed diets enriched with extra-virgin olive oil had higher levels of autophagy and reduced levels of amyloid plaques and phosphorylated tau,” he said. The latter substance is responsible for neurofibrillary tangles, which might contribute to the nerve cell dysfunction in the brain that is responsible for Alzheimer’s memory symptoms.

To investigate the relationship between extra-virgin olive oil and dementia, the researchers used a well-established Alzheimer’s disease mouse model. Known as a triple transgenic model, the animals develop three key characteristics of the disease: memory impairment, amyloid plagues, and neurofibrillary tangles.

The researchers divided the animals into two groups, one that received a chow diet enriched with extra-virgin olive oil and one that received the regular chow diet without it. The olive oil was introduced into the diet when the mice were six months old, before symptoms of Alzheimer’s disease begin to emerge in the animal model.

In overall appearance, there was no difference between the two groups of animals. However, at age 9 months and 12 months, mice on the extra virgin olive oil-enriched diet performed significantly better on tests designed to evaluate working memory, spatial memory, and learning abilities.

Delayed Eating May Result In Weight Gain and Poor Fat Metabolism

Aug 7, 2017

1487

Results from first-time study on delayed eating versus daytime eating revealed that delayed eating may raise cholesterol, fasting glucose, insulin and triglyceride levels.

Results from a new research propose that eating late at night could be more harmful. When compared to eating early, long delayed eating can elevate insulin and cholesterol levels and can increase weight. Delayed eating at night could negatively affect fat metabolism and hormonal markers associated with heart disease, diabetes and other diseases, as per reports from the researchers' team at the Perelman School of Medicine at the University of Pennsylvania.

Namni Goel, PhD, lead author of the study who is a research associate professor of psychology in Psychiatry in the division of Sleep and Chronobiology, said that, we understand from our research that when you were sleep deprived, it impacts negatively on weight and metabolism in part because of late-eating, however these initial results, which control for sleep give a detailed information of early eating in the day time. Late-eating can increase a negative profile of energy, weight and hormone markers including higher glucose and insulin, which are associated in diabetes, and triglycerides and cholesterol which are connected with cardiovascular diseases and other health issues.�

Nine healthy weight adults were included for this study; they underwent two conditions, one of daytime eating and other of delayed eating for eight weeks. Daytime eating included three meals and two snacks between 8 a.m. and 7 p.m. Delayed eating group had three meals and two snacks between noon to 11 p.m. The sleep duration remained constant as 11 p.m. to 9 a.m. The washout period was two weeks to ensure that there was no carry over impact.

Metabolic rates and blood tests of the participants were recorded at Penn's Center for Human Phenomic Science, at the beginning of the study, after the first eating condition, including two-week washout and after second eating condition. This let the researchers to record the changes in metabolism, weight and energy utilized and made ensure the washout permitted all values to return to baseline before the second condition.

Delayed Eating Versus Daytime Eating

Researchers observed that when participants had delayed eating, compared to daytime eating, there was an increase in weight. Respiratory quotient also was raised, carbohydrate metabolism increased and fewer lipids were metabolized due to delayed eating. Other measures showed that negative metabolic profiles got increase in delayed eating conditions; these include insulin, cholesterol, fasting glucose and triglyceride levels.

With the help of 24-hour hormonal profile, researchers also observed that in daytime eating, the hormone for appetite stimulation, ghrelin, peaked in the daytime while leptin which makes you feel satiated peaked later. This suggested that participants received stimulation to ear earlier and felt satisfied longer and could also avoid overeating in the evening and at night.

Melatonin levels remained the same in both groups since the sleep-wake cycles were constant.

Kelly Allison, PhD, senior author on the study, who serves as an associate professor of psychology in Psychiatry and director of the Center for Weight and Eating Disorders, said that lifestyle changes are difficult thing to do but eating early may help you to avoid these health effects. We have detailed knowledge of how overeating impacts body weight and health, however currently we have a clear understanding of how the foods are processed in our body at various times of day for a long duration.�

This is the first long-term study observing the timing of eating patterns that also managed sleep-wake cycles, exercise, macronutrient intake, etc. to find the impacts of prolonged delayed eating at different times of the day.

Obstructive Sleep Apnea Can Lead To Hypertension and Diabetes

Aug 7, 2017

1916

According to studies, sleep apnea among young and middle aged adults is linked with increased health risks.

Preliminary reports from two studies propose that mild-to-moderate obstructive sleep apnea is linked to an increased risk of developing diabetes and hypertension.

What Is Sleep Apnea?

About 30 million adults in the United States have obstructive sleep apnea, says the American Academy of Sleep Medicine. In this chronic disorder, there will be repeated obstruction in the upper airway while the person is sleeping. The usual warning symptoms include snoring and too much daytime sleepiness.

Alexandros N. Vgontzas, MD, principal investigator and lead author, who serves as Professor in the Department of Psychiatry at Pennsylvania State University College of Medicine said, we discovered that even mild sleep apnea was highly linked with increased risk of developing hypertension by 4 times as in comparison with persons without sleep apnea. In the same way, moderate sleep apnea was linked with increased risk for diabetes development by nearly 3 times when compared to people without sleep apnea.�

Young and middle-aged adults were found to have strong links as per the results.

Yun Li, MD, postdoctoral scholar and lead author of the study said, our findings recommend that early diagnosis and treating mild-to-moderate sleep apnea is necessary to avoid future cardiometabolic disease in young and middle-aged adults. As the link between sleep apnea and metabolic abnormalities were stronger in this age group, importance should be given on annual monitoring of indices of metabolic disorders and lifestyle interventions including healthy diet, weight control, stress management and regular exercise.�

While earlier research has showed the link between severe sleep apnea and increased risk for developing diabetes and hypertension, information about mild-to-moderate sleep apnea were unknown.

These two studies involved the Penn State Adult Cohort, a random common population sample of 1,741 adults. Participants took a comprehensive medical history interview at baseline and were reviewed in a sleep center during an overnight sleep study. The participants who do not have hypertension or diabetes at baseline were evaluated after 10 years.

Frequent sexual activity can boost brain power in older adults

Aug 6, 2017

1652

More frequent sexual activity has been linked to improved brain function in older adults, according to a study by the Universities of Coventry and Oxford.

Researchers found that people who engaged in more regular sexual activity scored higher on tests that measured their verbal fluency and visuospatial ability.

The study, published in�The Journals of Gerontology, Series B: Psychological and Social Sciences, involved 73 people aged between 50 and 83.

Participants answered the questionnaire on how often (never, monthly or weekly), on average, they had engaged in sexual activity over the past 12 months and about their general health and lifestyle.

The 28 men and 45 women took part in a standardized test, which is used to measure different patterns of brain function in older adults, focusing on attention, memory, fluency, language and visuospatial ability.

This included verbal fluency tests in which participants had 60 seconds to name as many animals as possible, and say as many words beginning with F — tests which reflect higher cognitive abilities. Also included was copying a complex design and drawing a clock face from memory to determine their visuospatial ability.

It was these two sets of tests where participants who engaged in weekly sexual activity scored the highest, with the verbal fluency tests showing the strongest effect.

The results suggested that frequency of sexual activity was not linked to attention, memory or language. In these tests, the participants performed just as well regardless of whether they reported weekly, monthly or no sexual activity.

This study expanded on previous research from 2016, which found that older adults who were sexually active scored higher on cognitive tests than those who were not sexually active.

Lead researcher Dr. Hayley Wright, from Coventry University’s Centre for Research in Psychology, Behaviour and Achievement say that they can only speculate whether this is driven by social or physical elements and that further research could look at how biological elements, such as dopamine and oxytocin, could influence the relationship between sexual activity and brain function to give a fuller explanation of their findings.

Acetaminophen during pregnancy can inhibit masculinity

Aug 5, 2017

1405

Paracetamol (acetaminophen) is popular for relieving pain. But if you are pregnant, you should think twice before popping these pills according to the researchers in a new study. In an animal model, Paracetamol, which is the pain-relieving substance found in the pills, actually damages the development of male behaviours.

Previous studies have shown the paracetamol can inhibit the development of the male sex hormone testosterone in male foetuses, thus increasing the risk of malformation of the testicles in infants. But a reduced level of testosterone at the fetal stage is also significant for the behaviours of adult males, says Ph.D. David Møbjerg Kristensen, a researcher at the Department of Biomedical Sciences and the Novo Nordisk Foundation Center for Protein Research at the Faculty of Health and Medical Sciences.

“We have demonstrated that a reduced level of testosterone means that male characteristics do not develop as they should. This also affects sex drive. In a trial, mice exposed to paracetamol at the fetal stage were simply unable to copulate in the same way as our control animals. Male programming had not been properly established during their fetal development and this could be seen long afterward in their adult life. It is very worrying,” says Kristensen.

The dosage administered to the mice was close to the recommended dosage for pregnant women. Because the trials are restricted to mice, the results could be different to humans. However, the researchers’ certainty about the harmful effects of paracetamol means it would be unethical to undertake the same trials on humans.

“People should think carefully before taking any medicine. These days it has become so common to take paracetamol that we forget it is a medicine and all medicine has side effects. If you are ill, you should naturally take the medicine you need. After all, having a sick mother is more harmful to the fetus,” says Kristensen.

He emphasizes that pregnant women should continue to follow the guidelines given by their country’s health authorities and recommends people to contact their GP if in doubt about the use of paracetamol.

Video games can change your brain

Aug 3, 2017

1504

Studies investigating how playing video games can affect the brain have shown that they can cause changes in many brain regions

Scientists have collected and summarized studies looking at how video games can shape our brains and behavior. Research to date suggests that playing video games can change the brain regions responsible for attention and visuospatial skills and make them more efficient. The researchers also looked at studies exploring brain regions associated with the reward system, and how these are related to video game addiction.

Video games are becoming more common and are increasingly enjoyed by adults. The average age of gamers has been increasing, and was estimated to be 35 in 2016. Many committed gamers play on desktop computers or consoles, but a new breed of casual gamers has emerged, who play on smartphones and tablets at spare moments throughout the day. Video games are an increasingly common form of entertainment, but do they have any effect on our brains and behavior?

Over the years, the media have made various sensationalist claims about video games and their effect on our health and happiness. “Games have sometimes been praised or demonized, often without real data backing up those claims. Moreover, gaming is a popular activity, so everyone seems to have strong opinions on the topic,” says Marc Palaus, first author on the review, recently published in�Frontiers in Human Neuroscience.

Palaus and his colleagues wanted to see if any trends had emerged from the research to date concerning how video games affect the structure and activity of our brains. They collected the results from 116 scientific studies, 22 of which looked at structural changes in the brain and 100 of which looked at changes in brain functionality and/or behavior.

The studies show that playing video games can change how our brains perform, and even their structure. The brain regions involved in attention are also more efficient in gamers and require less activation to sustain attention on demanding tasks.

There is also evidence that video games can increase the size and efficiency of brain regions related to visuospatial skills.

Blood pressure lowering benefits patients with chronic kidney disease

Aug 2, 2017

1805

Results from a recent clinical trial indicate that intensive blood pressure lowering reduces chronic kidney disease (CKD) patients’ risks of dying prematurely or developing cardiovascular disease. The findings appear in an upcoming issue of the Journal of the American Society of Nephrology (JASN).

The appropriate target for blood pressure in patients with CKD and hypertension has been unclear. To examine the issue, researchers analyzed information from the Systolic Blood Pressure Intervention Trial (SPRINT), sponsored by the National Institutes of Health. SPRINT, which enrolled individuals aged greater than 50 years with systolic blood pressure of greater than 130 mmHg and at least one additional cardiovascular disease risk factor, compared targeting a systolic blood pressure to <120 mmHg vs. <140 mmHg for preventing cardiovascular complications and early death. The benefits of the lower target were apparent almost a year before the study was initially planned to end.

Alfred K. Cheung, MD (University of Utah) and company, found that individuals who had CKD at the start of the study experienced similar benefits as those without CKD. After a median follow-up of 3.3 years for 1330 CKD patients in the intensive group and 1316 in the standard group, the composite cardiovascular outcome (heart attack, acute coronary syndrome, acute decompensated heart failure, stroke, or heart-related death) occurred in 112 and 131 participants, respectively, translating to a 19% reduction in risk for intensive-group participants. Also, there were 70 deaths from any cause in the intensive group compared with 95 in the standard group, for a 28% reduction in risk.

Researchers found that older participants aged ?75 years benefited as much as those who were younger within this CKD subgroup. There was a slightly faster decline in kidney function in the intensive group, but no serious adverse events.

The author noted that, in people with CKD, lowering systolic blood pressure beyond the conventional goal reduced the risks of heart disease and death, but slightly hastened the decline in kidney function that often accompanies aging. These findings come from the largest randomized trial to date on the effects of blood pressure in patients with CKD.

Vegetable protein may protect against early menopause

Aug 1, 2017

1530

Study shows modest but significant lower risk

Results of a new study from epidemiologists at the University of Massachusetts Amherst and Harvard T.H. Chan School of Public Health suggest that long-term, high intake of vegetable protein from such foods as whole grains, soy, and tofu, may protect women from early menopause and could prolong reproductive function.

“A better understanding of how dietary vegetable protein intake is associated with ovarian aging may identify ways for women to modify their risk of early onset menopause and associated health conditions,” write first author Maegan Boutot, with her advisor, Professor Elizabeth Bertone-Johnson. Details appear in the current online edition of the�American Journal of Epidemiology.

According to the authors, early menopause or the cessation of ovarian function before age 45, affects about 10 percent of women and is associated with higher risk of cardiovascular disease, osteoporosis, and early cognitive decline. Few studies have evaluated the link between protein intake and menopause timing, and this is the first to look specifically at early menopause.

Researchers evaluated the relationship between diet and risk of early menopause among members of the Nurses’ Health Study II (NHS2), an ongoing prospective study of 116,000 women aged 25-42 when they entered it in 1989.

Participants were asked to report the frequency of consumption in a single serving of 131 foods, beverages and supplements over the previous year, from “never or less than once a month” to “6+ per day.” They observed that women consuming approximately 6.5 percent of their daily calories as vegetable protein had a significant 16 percent lower risk of early menopause compared to women whose intake was approximately 4 percent of calories.

Relatively few women in the study consumed high levels of vegetable protein and analyses was limited, women consuming 9 or more percent of their calories from vegetable protein had a hazard ratio of 0.41 (95 percent confidence interval = 0.19-0.88) compared to those eating less than 4 percent.

The authors suggest that more prospective studies of their findings are warranted, including soy-based and non-soy vegetable proteins comparison.

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