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Scientists have developed a rapid, highly accurate test to detect antibodies against the spike protein of SARS-CoV-2 in human serum, opening a new avenue for understanding the full extent of the pandemic and evaluating the effectiveness of vaccines.
In the 18 months since the emergence of Covid-19 pandemic, great strides have been made in discovering and inventing various approaches to track and control the spread of the SARS-CoV-2 virus. Rapid and accurate diagnosis has always been vital in this regard. The gold standard since the beginning of the pandemic has been the RT-PCR method; however, it is time-consuming, labor-intensive, and requires sophisticated equipment, and can only detect the presence of viral RNA in the samples.
A team of scientists from Japan, including Professor Manabu Tokeshi of Hokkaido University’s Faculty of Engineering, have developed a 20-minute test to detect and quantify antibodies against SARS-CoV-2 in human serum. Their findings were published in the journal Biosensors and Bioelectronics.
It is estimated that between 40% to 45% of individuals infected with SARS-CoV-2 are asymptomatic — despite being infected, they do not develop any symptoms of the disease. Identifying individuals who may have had asymptomatic Covid-19 is important to understanding the full extent of the pandemic. RT-PCR can only detect the presence of the viral RNA in samples; individuals who have recovered from the pandemic will only have antibodies to the virus, which RT-PCR cannot detect.
There are commercially available tests to detect the presence of antibodies against SARS-CoV-2; however, the majority of these tests are inaccurate. Lateral flow immunoassay is one of the most common tests for diagnosis of Covid-19 based on antibody detection. While rapid, it is a qualitative method, and cannot be used for the quantification of antibodies. Further, the method does not scale well, resulting in a low cost efficiency.
The scientists developed a method of detecting antibodies against SARS-CoV-2 in human serum using a method called non-competitive fluorescence polarization immunoassay (FPIA). This method is not just rapid, but can also be used to quantify the antibodies. FPIA has been used in the food and medical industry; the team has previously made many innovations to the method and associated equipment, including the development of a portable fluorescence polarization analyzer.
FPIA requires fluorescently-labelled recombinant SARS-CoV-2 spike proteins (F-RBD) and human serum to be mixed together for the test. Individuals who have been infected with or vaccinated against SARS-CoV-2 will have anti-spike protein antibodies in their serum. When these antibodies bind to F-RBD, polarised light is emitted, while F-RBD alone emits depolarized light. By measuring the degree of polarisation using a fluorescence polarization analyser, the concentration of antibodies can be determined. The scientists optimised the test and evaluated it using samples of human serum from individuals diagnosed with Covid-19 and from those who had not been infected by SARS-CoV-2.
The test was demonstrated to be highly accurate, quick and easy to perform, with high throughput. This test requires about 20 minutes to complete, compared to about 2 hours for other tests; furthermore, the equipment required for the test is highly portable, weighing only 4.3 kg. Taken all together, these features make the test an excellent option for detecting and quantifying antibodies against SARS-CoV-2. The test can now be used for two purposes: screening large populations to determine the exact extent of the pandemic, and from evaluating the effectiveness of SARS-CoV-2 vaccines based on the antibody response.
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At this very moment, the billions of neurons in your brain are using their trillions of connections to enable you to read and comprehend this sentence.
Now, by studying the neurons involved in the sense of smell, researchers from Kyushu University’s Faculty of Medical Sciences report a new mechanism behind the biomolecular bonsai that selectively strengthens these connections.
How neuronal circuits remodel themselves over time, especially during early development, is an open question in neurobiology. At the start of neuronal development, neurons form excessive amounts of connections that are gradually eliminated as others are strengthened.
Studying a type of olfactory neuron known as a mitral cell in mice, the research team found that the protein BMPR-2 is one of the key regulators of selective stabilization of neuron branching and that the strengthening only happens when the branch receives signals from other neurons.
“A main reason we use olfactory neurons is because they are easy to access and study, and mitral cells develop only a single branch,” explains Shuhei Aihara, first author of the study published in Cell Reports.
“When an olfactory neuron detects a specific molecule that we smell, it sends the signal to a specific ‘way station’ in the brain’s olfactory bulb called a glomerulus. That signal is then relayed to the brain through mitral cells. One mitral cell receives signals for one specific smell.”
At a very early stage in development, these mitral cells send branches into many glomeruli. As time progresses, these branches — known as dendrites — are pruned away to leave only a single, strong connection. The research team set out to uncover what kind of molecular cues caused one branch to be favored over others.

The mitochondrion has garnered quite the reputation for its role as the “powerhouse of the cell.” These tiny, but mighty organelles play various life-sustaining roles, from powering our own cells and organs to fueling chemical and biological processes. But when they aren’t working properly, a number of rare diseases can occur.
Mitochondrial diseases are a group of debilitating genetic disorders that affect one in 5,000 people throughout the world, most of them being children. Along with these diseases come a variety of health concerns including, but not limited to, heart disease, developmental and cognitive disabilities, respiratory issues, poor growth, and even premature death. As of this moment, there is no cure.
But recent work published in the journals Mitochondrion and BMC Molecular and Cell Biology by Aloka Abey Bandara, a research associate professor in the Department of Biomedical Sciences and Pathobiology in the Virginia-Maryland College of Veterinary Medicine, and his team offers mitochondrial disease patients and their parents a glimmer of hope.
Along with a team of Virginia Tech researchers across Blacksburg and Roanoke, Bandara has successfully created live cell models that mimic mitochondrial disease cells. These cells will lay the groundwork for drug studies and future studies into mitochondrial diseases.
“Our cell models will allow us to see what exactly happens to the cells and its processes when a child develops mitochondrial disease. In addition to these factors, we will be able to conduct further study into the toxicity and effectiveness of novel drug candidates,” said Bandara, who is also an affiliated faculty member of the Fralin Life Sciences Institute.
Our bodies produce life-sustaining energy from the food we eat and the air we breathe. Oxygen and nutrients, like glucose, travel throughout the body’s organs, tissues, and cells until they arrive at their final destination: the mitochondria. When the nutrients reach the inner membrane of the mitochondria, a unique series of protein complexes, called the electron transport chain, kicks into gear.

University of Otago scientists have opened the door to improved treatment of brain dysfunction which causes psychosis.
Dr Ryan Ward, of the Department of Psychology, says he and a team of researchers have been working on ways to model schizophrenia symptoms in animal models.
“Psychosis is a debilitating aspect of schizophrenia and, while current drugs treat it well, they have horrendous side effects which lead to poor quality of life for patients. Research which can identify specific mechanisms of the dysfunction can provide more precise drug targets for treatment, improving patient outcomes and quality of life. “We have been particularly interested in modelling symptoms which have historically been difficult. One that is particularly difficult to model in non-humans is psychosis, because of the challenge of assessing subjective internal state.
“We have recently broken new ground, thanks to the Masters thesis work of Wayne Meighan, by combining a rat model of schizophrenia risk with a procedure which allows a very sensitive screening for subjective internal state,” he says.
In a study published in the Journal of Psychopharmacology, researchers measured the ability of rats which model a risk factor for schizophrenia to tell the difference between a drug (ketamine) and saline.
Dr Ward says the critical aspect is that the dose of ketamine used causes schizophrenia-like psychosis in humans.
“We found that our model was impaired at discriminating the drug from saline only at doses that cause psychosis in humans. We believe this means that the subjective internal state of these models is similar to the state induced in human psychosis.
“This opens up a way to model in non-humans symptoms that were previously thought to be only measurable in humans, such as psychosis. The finding may greatly enhance our ability to pinpoint brain mechanisms of these symptoms and lead to more effective treatments,” he says.
Dr Ward says figuring out how to model psychiatric disease is often about being able to ask the question in the right way.
“In our case, we demonstrated that it is possible to ask an animal how it ‘feels’ in a rigorous way.
“These types of studies open the door for further work in which we may be able to identify specific brain dysfunction that produces psychosis, improving future treatments.”
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Combined perceptions of the risk and availability of cannabis influence the risk of cannabis use more than perceived risk and perceived availability alone, according to a new study at Columbia University Mailman School of Public Health. Researchers observed that those who perceived cannabis as low-risk and available were more likely to report using the drug in the past year and almost daily compared to those individuals who perceived cannabis as high-risk and unavailable. This is the first study to consider the joint effects of perceived risk and perceived availability. The results are published in the journal Drug and Alcohol Dependence.
“Our study described the evolution of joint perceptions of cannabis risk and availability from 2002-2018 and estimated the relationship between combined perceptions and past-year cannabis use, frequent use, and cannabis use disorder,” said Natalie Levy, MPH, doctoral student in the Department of Epidemiology at Columbia Mailman School, and first author. “Studying perceived risk and availability in conjunction revealed more nuanced patterns than considering each perception in isolation..”
Using data on 949,285 participants from the National Surveys on Drug Use and Health from 2002-2018, researchers observed that the prevalence of perceiving cannabis use as low-risk doubled over this period while the prevalence of perceiving cannabis as available increased only marginally. When looking at joint categories of perceived risk and perceived availability, they found that prevalence of perceiving cannabis as both low-risk and available increased, from 17 percent in 2002 to 36 percent in 2018 while the proportion of the population perceiving cannabis as high-risk and available or high-risk and unavailable declined. By 2018, a larger proportion of the population perceived marijuana as low-risk and available (36 percent) than both high-risk and available and high-risk and unavailable, at 26 percent and 27 percent, respectively.
Individuals who perceived cannabis as low-risk were six times more likely to have used cannabis in the past-year than individuals who perceived the drug as high-risk. Similarly, individuals who perceived cannabis as available were five times more likely to have used cannabis in the past year than individuals who perceived it as unavailable. However, individuals who perceived marijuana as both low-risk and available were 22 times more likely to have used the drug in the past year than those who perceived cannabis as high-risk and unavailable.
In 2018, most individuals who reported no past-year cannabis use perceived cannabis as high-risk, whether or not they distinguished between its availability or non-availability. In contrast, the majority of individuals who used cannabis in the past year perceived the drug as low-risk and available and this perception rose to even higher levels among those reporting frequent use.
Cannabis perceptions also differed by gender. Overall, a larger proportion of males viewed cannabis as lower risk and more available compared with females, but patterns differed by age. “We found minimal differences in perceptions by gender in the 12-17-year age group while among all those 18 years of age and older, the prevalence of perceiving cannabis as low-risk and available was higher for males than females; perceiving cannabis as high-risk and unavailable was more common among females in every year,” noted Levy.
“Our results provide an important starting point for exploring specific hypotheses regarding the effects of perceptions on individual cannabis outcomes and highlight the importance of exploring perceived risk and availability together,” said Silvia Martins, MD, PhD, Columbia Mailman School associate professor of Epidemiology, director of the Substance Use Epidemiology Unit of the Department of Epidemiology, and senior author. “For example, our findings suggest that prevention efforts that focus only on the risks of cannabis use may be less effective among individuals who perceive cannabis as easily available.
“Trends in perceptions — especially among younger age groups — may also identify priority groups for intervention,” observed Levy. “Further understanding of these relationships is particularly important in light of rapidly changing cannabis policies, a contextual factor that may influence perceptions of both risk and availability of cannabis and subsequent use.”

Heart problems in children hospitalized with multisystem inflammatory syndrome (MIS-C) — an inflammatory condition triggered by COVID — were mostly gone within a few months, a new study by researchers at Columbia University Vagelos College of Physicians and Surgeons and NewYork-Presbyterian has found.
The study published in Pediatrics about 45 MIS-C patients is the first in North America to report on longitudinal cardiac and immunologic outcomes in children hospitalized with MIS-C.
“We’ve learned that COVID causes a spectrum of illness in children. Some are asymptomatic or mildly symptomatic and a small number of kids who develop MIS-C become critically ill, requiring admission to the ICU,” says Kanwal M. Farooqi, MD, assistant professor of pediatrics at Columbia University Vagelos College of Physicians and Surgeons and first author of the study. “It is a relief that this study shows that most of the severe heart and immunologic manifestations we saw in kids with MIS-C resolved rapidly.”
MIS-C is a rare condition triggered by SARS-CoV-2 infection that causes widespread inflammation throughout the body. Many children with MIS-C were asymptomatic or had mild COVID symptoms at first but weeks later developed a variety of nonrespiratory symptoms including abdominal pain, skin rashes, heart abnormalities, and, in some cases, vasodilatory shock (extremely low blood pressure).
Some of the first MIS-C cases in the United States were seen in spring 2020 by Columbia pediatricians at NewYork-Presbyterian Morgan Stanley Children’s Hospital.
“It was both challenging and scary, because we didn’t know how these patients would do long term, especially in terms of cardiac and immunologic abnormalities, which were the most prominent issues at the time,” says Farooqi, who is also a pediatric cardiologist at NewYork-Presbyterian Morgan Stanley Children’s Hospital.

Patients who experience long COVID have reported more than 200 symptoms across 10 organ systems*, in the largest international study of ‘long-haulers’ to date, led by UCL scientists together with a patient-led research collaborative.
For the study, published in the Lancet’s EClinicalMedicine, patient researchers who connected through the Body Politic online COVID-19 support group created a web-based survey designed to characterise the symptom profile and time course in patients with confirmed or suspected long COVID, along with the impact on daily life, work, and return to health.
With responses from 3,762 eligible participants from 56 countries, the researchers identified a total of 203 symptoms in 10 organ systems; of these, 66 symptoms were tracked for seven months. The most common symptoms were fatigue, post-exertional malaise (the worsening of symptoms after physical or mental exertion), and cognitive dysfunction, often called brain fog.
Of the diverse range of symptoms, others included: visual hallucinations, tremors, itchy skin, changes to the menstrual cycle, sexual dysfunction, heart palpitations, bladder control issues, shingles, memory loss, blurred vision, diarrhea, and tinnitus.
The research team, who have all had or continue to have long COVID, are now calling for clinical guidelines on assessing long COVID to be significantly widened beyond currently advised cardiovascular and respiratory function tests to include neuropsychiatric, neurological, and activity intolerance symptoms.
Furthermore, with large numbers of long haulers ‘suffering in silence’, the authors advocate that a national screening programme, accessible to anyone who thinks they have long COVID, should be undertaken. Given the heterogeneous (diverse) make-up of symptoms that affect multiple organ systems, it is only by detecting the root cause that patients will receive the correct treatment.

A small regulatory RNA found in many problematic bacteria, including Escherichia coli, appears to be responsible for managing the response of these bacteria to environmental stresses. Professor Charles Dozois from Institut national de la recherche scientifique (INRS) and doctoral student Hicham Bessaiah see a promising avenue for more effective treatment of antibiotic-resistant bacteria. Their results have been published in the journal PLOS Pathogens.
In conducting their work, the researchers and their team observed that the elimination of this regulatory RNA sequence had an effect on urinary tract infections related to E. coli. These infections are among the world’s most common, especially in women, but they are sometimes hard to treat due to antibiotic resistance.
E. coli is normally found in the intestinal flora, but when it migrates to the bladder, the conditions there are completely different. The bacteria have to withstand the environmental stressors in order to cause a bladder infection. “Without the regulatory RNA, the bacteria is more sensitive to changes in the environment and loses its infectious capacity,” explained the doctoral student.
Inhibiting the RNA sequence
The idea is to block the RNA and make the bacteria less infectious, especially in the case of chronic infection, which can lead to increased resistance to treatment. If the bacteria are less resistant to stress, it will be more vulnerable to the host’s immune response. Regulation of the systems that make it virulent will also be disrupted.
“People with recurrent urinary tract infections take antibiotics regularly. This leads to resistance and limits treatment options, which is why it’s important to find alternatives,” explained Professor Dozois.
The relationship between virulence and stress isn’t unique to urinary tract infections. The regulatory RNA sequence studied by the researchers is also found in a number of other major pathogenic bacteria. Given that the RNA seems to impact multiple functions, the research group is working to better understand the mechanisms of regulation before pursuing additional research on antibiotic-resistant strains of bacteria.
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Materials provided by Institut national de la recherche scientifique – INRS. Note: Content may be edited for style and length.

Resistance to antibiotics is common and often deadly among children with pneumonia in Bangladesh, according to a new study coauthored by researchers from Massachusetts General Hospital (MGH) with colleagues at the International Centre for Diarrhoeal Disease Research, Bangladesh (abbreviated as icddr,b). This study, which appears in the journal Open Forum Infectious Diseases, offers an early warning that a pandemic of potentially deadly antibiotic resistance is under way and could spread around the globe.
The study was led by Mohammod Jobayer Chisti, MD, PhD, a senior scientist in icddr,b’s Nutrition and Clinical Services Division. Chisti was inspired to conduct the research when he observed that the hospital affiliated with icddr,b was admitting more and more young children with pneumonia who were highly resistant to treatment with standard antibiotics. “At our hospital, dozens of kids died of pneumonia between 2014 and 2017, despite receiving the World Health Organization’s recommended antibiotics and enhanced respiratory support,” says Chisti.
Pneumonia is an infection of the lungs that causes fluid and pus to fill air sacs, producing cough, fever, trouble breathing, and other symptoms. Without effective treatment, the infection can be fatal; pneumonia is the most common cause of death in young children, according to the World Health Organization. In small children, pneumonia can be caused by viruses, but certain types of bacteria are common sources of infection, too. In the United States and other high-income countries, Staphylococcus (“staph”), Streptococcus (“strep”), and Haemophilus influenzae are the most common bacterial causes of pneumonia, which usually respond well to antibiotic therapy. Vaccines for the latter two have saved countless lives worldwide.
However, when Chisti and his colleagues examined health records of more than 4,000 children under age five with pneumonia admitted to their hospital between 2014 and 2017, they found that a very different pattern of bacterial infections was occurring. The usual staph and strep infections that commonly cause pneumonia in the United States and elsewhere were relatively rare. Among the children who had a positive culture, gram-negative bacteria were responsible for 77 percent of the infections, including Pseudomonas, E. coli, Salmonella and Klebsiella.
“That’s totally different than what I’m used to in my practice in Boston,” says Jason Harris, MD, MPH, co-first author of the study and chief of the division of Pediatric Global Health at the Massachusetts General Hospital for Children. Unfortunately, he adds, “the gram-negative bacteria we saw in these kids are notorious for being antibiotic resistant.” To wit: Some 40 percent of the gram-negative bacterial infections in this study resisted treatment with first- and second-line antibiotics that are routinely used to treat pneumonia. More alarming, children who had antibiotic-resistant bacterial infections were 17 times more likely than others without bacterial infections to die.
Harris believes that these results are clear evidence that longstanding concerns that antibiotic resistance will become a deadly menace are no longer theoretical — the problem has taken root. “These kids are already dying early because of antibiotic-resistant bacteria, from what would be a routine infection in other parts of the world,” says Harris. “And this was at one hospital in Bangladesh. Extrapolate these findings across a country of 163 million people, and then to a larger region where antibiotic resistance is emerging, and the overall numbers are probably huge.”
There is an urgent need to address factors that are promoting antibiotic resistance in Bangladesh, says Tahmeed Ahmed, PhD, executive director of icddr,b and senior author of the study. For starters, antibiotics can be purchased without a prescription in the country and many people use them to self-treat conditions such as dysentery, cold, cough and fever. Misuse of antibiotics promotes the spread of bacteria that resist the medications. “We may be able to reduce this emerging bacterial resistance by improving antibiotic stewardship, particularly in the outpatient setting,” says Ahmed. Lab testing for diagnosis of bacterial infections is also inadequate in the country. “What’s more, lack of access to clean water and adequate sanitation helps spread bacteria that are resistant to antibiotics,” adds Ahmed. Improvements in health care infrastructure and policy changes to rein in the misuse of antibiotics are essential, he argues, though Ahmed notes that Bangladesh’s health care system also needs better access to more advanced antibiotic therapies for resistant infections.
If these and other steps aren’t taken now, it’s only a matter of time before the problem of widespread deadly antibiotic resistance spreads around the world, notes Harris. “We know that acquisition of antibiotic resistance is very common in travelers, and that when highly resistant bacteria crop up in one part of the world, they ultimately crop up everywhere,” he says, comparing the problem to another current global health care crisis. “If COVID-19 was a tsunami, then emerging antibiotic resistance is like a rising flood water. And it’s kids in Bangladesh who are already going under.”
Harris is also an associate professor of pediatrics at Harvard Medical School.
This research was funded by unrestricted support to icddr,b from the governments of Bangladesh, Canada, Sweden and the United Kingdom. Harris receives funding from the National Institutes of Health.

Las personas que regularmente hacen ejercicios para fortalecer los músculos tienen entre 20 y 30 por ciento menos probabilidades de ser obesas con el tiempo.Levantar pesas un par de veces a la semana podría ayudarnos a prevenir la obesidad, según un nuevo e interesante estudio sobre el ejercicio de resistencia y la grasa corporal. Esta investigación muestra que quienes completan ejercicios de entrenamiento muscular de cualquier tipo tienen de un 20 a un 30 por ciento menos probabilidades de llegar a ser obesos que las personas que no los hacen, independientemente de si practican ejercicios aeróbicos o no.Los hallazgos indican que el entrenamiento con pesas podría ser más relevante para el control de peso de lo que muchos esperábamos y levantar un poco de peso nos podría ayudar a no subirlo después.La incidencia de obesidad en Estados Unidos está al alza, pues alrededor del 40 por ciento de los adultos cumplen con los criterios estandarizados para ser considerados obesos. Se prevé que esa cifra aumente a más de un 50 por ciento para fines de esta década.Por desgracia, pocos de nosotros perderemos los kilos de más que ya tenemos. La mayoría de las personas que pierde más del cinco por ciento de su peso corporal lo recupera a los cinco años.Por eso, es posible que la manera más eficaz de tratar la obesidad sea previniéndola. Y hacer ejercicio con frecuencia ayuda bastante. Muchos estudios muestran que la gente que camina con frecuencia o que hace actividades como correr, andar en bicicleta, nadar o practicar algún ejercicio aeróbico suele subir menos kilos al envejecer que las personas sedentarias, y tiene menos riesgo de llegar a ser obesa.Sin embargo, no se tiene tanta información sobre si los ejercicios de entrenamiento con pesas también influyen en el peso. Algunas investigaciones pasadas sugieren que el entrenamiento de resistencia ayuda a que las personas retengan masa muscular cuando intentan bajar de peso. Pero no queda muy claro si también podrían controlar la subida de peso a largo plazo y prevenir la obesidad.Así que, para el nuevo estudio, publicado en junio en PLOS Medicine, un grupo de investigadores de la Universidad Estatal de Iowa en Ames, Iowa, y otras instituciones, decidieron estudiar la posible relación entre las pesas y la circunferencia de las personas. Al inicio, se abocaron a la base de datos, que es grande y muy útil, compilada por el Aerobics Center Longitudinal Study, un famoso proyecto que había realizado un seguimiento del estado médico, de salud y la condición física de decenas de miles de pacientes que visitaron la clínica Cooper en Dallas entre 1987 y 2005. Los hombres y mujeres se sometieron a numerosas pruebas durante sus visitas recurrentes a la clínica.En esta ocasión, los investigadores de Iowa usaron los registros de más o menos 12.000 de los participantes, la mayoría de los cuales eran de mediana edad. Ninguno era obeso cuando se unió al Aerobics Center, según su índice de masa corporal, o IMC (esta medida calcula de manera indirecta la grasa corporal según la altura y el peso de la persona. Puedes calcular tu IMC aquí).Estos hombres y mujeres habían completado la típica serie de mediciones de salud y estado físico durante sus visitas a la clínica y también llenaron un cuestionario de ejercicio que indagaba, entre otras cosas, en el entrenamiento con pesas. Se les preguntaba si hacían “ejercicios de fortalecimiento muscular” y, en caso afirmativo, con qué frecuencia y durante cuántos minutos a la semana.Después, los investigadores empezaron a cotejar los datos, comparando los pesos y otras medidas de las personas entre cada visita a la clínica. Usando el IMC como medida, alrededor del siete por ciento de los hombres y mujeres se habían vuelto obesos en los seis años siguientes a su primera visita a la clínica.Pero el IMC es una aproximación poco precisa de la constitución corporal y no siempre es una medida exacta de la obesidad. Por eso, los investigadores también examinaron los cambios en el grosor de la cintura y el porcentaje de grasa corporal para determinar si se habían vuelto obesos. Según el criterio de un diámetro de cintura superior a 100 centímetros para los hombres y 90 para las mujeres, o un porcentaje de grasa corporal superior al 25 por ciento para los hombres y el 30 por ciento para las mujeres, hasta el 19 por ciento de los participantes desarrollaron obesidad con el paso de los años.RELATED: https://www.nytimes.com/es/2021/05/21/espanol/IMC-formula.htmlSin embargo, los investigadores descubrieron que el levantamiento de pesas cambió esos resultados, pues redujo de modo considerable el riesgo de que alguien pudiera ser obeso, sin importar qué parámetro de medición usaran. Los hombres y las mujeres que declararon haber fortalecido sus músculos varias veces a la semana, durante un total de una o dos horas semanales, tuvieron un 20 por ciento menos de probabilidades de padecer obesidad con el paso de los años, en función del IMC, y un 30 por ciento menos, en función del grosor de la cintura o del porcentaje de grasa corporal.Los beneficios no cambiaron cuando los investigadores controlaron las variables de edad, sexo, tabaquismo, la salud general y ejercicio aeróbico. La gente que hacía algún ejercicio aeróbico y levantaba pesas tenía muchas menos probabilidades de llegar a ser obesa. Pero lo mismo ocurría con los que solo levantaban pesas y decían hacer poco o casi nada de ejercicio aeróbico.Los resultados sugieren que “puedes obtener muchos beneficios de levantar pesas, aunque no lo hagas mucho”, afirma Angelique Brellenthin, profesora de kinesiología en la Universidad Estatal de Iowa, quien estuvo a cargo del nuevo estudio.Desde luego, la investigación fue observacional y no demuestra que el entrenamiento de resistencia prevenga el aumento de peso, solo que ambos factores están relacionados. Tampoco consideró la dieta, la genética ni los hábitos de salud de las personas, los cuales podrían incidir en el riesgo de padecer obesidad.Tal vez lo más importante es que no nos dice cómo influye el fortalecimiento muscular en el peso, aunque es probable que el entrenamiento de resistencia aumente y mantenga la masa muscular, indica Brellenthin. Al ser un tejido activo en términos metabólicos, el músculo quema calorías y aumenta de manera leve nuestra tasa metabólica. Curiosamente, el efecto deseable de añadir masa muscular también puede explicar por qué menos levantadores de pesas se consideraban obesos cuando los investigadores utilizaron el IMC como medida. El IMC no distingue el músculo de la grasa, señala Brellenthin. Si se añade músculo al cuerpo con el entrenamiento de pesas, el IMC puede aumentar.Sin embargo, el mensaje principal del estudio es que es probable que un poco de entrenamiento con pesas ayude a controlar el peso, a la larga. “Así que mi consejo sería incorporar algunos ejercicios de resistencia antes o después de que salgas a tu caminata diaria”, sugiere Brellenthin. O inscríbete a un gimnasio o clase en línea. O prueba una rutina sencilla de resistencia que puedas hacer en casa, como el ciclo de ejercicios de 7 minutos de pie.