August 20, 2008, 8:21 PM CT

Childhood ear infections may predispose to obesity later in life

Scientists are reporting new evidence of a possible link between a history of moderate to severe middle ear infections in childhood and a tendency to be overweight during the later part of life. Their study suggests that prompt diagnosis and therapy of middle ear infections one of the most common childhood conditions requiring medical attention may help fight obesity in some people. The findings were presented today at the 236th National Meeting of the American Chemical Society (ACS).

Study leader Linda M. Bartoshuk, Ph.D., noted that chronic, repeated ear infections can damage the chorda tympani nerve, which passes through the middle ear and controls taste sensations. Damage to this nerve appears to intensify the desire for fatty or high-energy foods, which could result in obesity, she said.

Other research has shown that middle ear infections, or otitis media, are becoming more common in children. Childhood obesity is likewise on the rise and has reached epidemic levels, especially in the United States. Eventhough researchers have known for years that ear infections can lead to hearing loss in children that can result in speech and language impairment, a possible link between ear infections and obesity has been largely unexplored until now, said Bartoshuk, who is with the University of Florida's Center for Smell and Taste in Gainesville......... Posted by: JoAnn      Read more         Source

March 13, 2008, 9:12 PM CT

Link between common cold and ear infection

A new five-year study at the University of Texas Medical Branch at Galveston confirms the suspected close link between the two most common diseases of young children: colds and ear infections.

The study, which appears in the March 15 issue of Clinical Infectious Disease, confirmed the suspected close link between the two most common diseases of young children, viral colds and ear infections. It also identified the viruses linked to higher rates of ear infections.

Understanding how viruses and ear infections are linked will definitely help us find new ways to prevent ear infections, said Dr. Tasnee Chronmaitree, a pediatric infectious disease specialist who is the studys principal investigator. To break the link you must first understand it.

Ear infections are the driving force behind antibiotic resistance, a troubling medical issue, as physicians often administer antibiotics for the painful, persistent ailment.

Chonmaitree has studied otitis media (ear infection) for more than two decades. She said parents could best protect their children by avoiding exposure to sick children and to have their children vaccinated against influenza. She suggested that children in day care might face reduced exposure to viruses if they are enrolled in smaller day care facilities with fewer children......... Posted by: Sue      Read more         Source

January 28, 2008, 10:50 PM CT

Over-the-counter eardrops may cause hearing loss

A new study, led by scientists at The Montreal Childrens Hospital (MCH) of the MUHC, has revealed that certain over-the-counter earwax softeners can cause severe inflammation and damage to the eardrum and inner ear. The results of the study, recently published in The Laryngoscope, suggest that use of these medications should be discouraged.

Patients often complain that wax is blocking their ears and is causing discomfort and sometimes deafness, says Dr. Sam Daniel principal investigator of the study and director of McGill Auditory Sciences Laboratory at The Childrens. Over-the-counter earwax softeners are used to breakup and disperse this excess wax. However, the effects of these medications on the cells of the ear had not been thoroughly analyzed.

Because some of these products are readily available to the public without a consultation with or prescription from a physician, it is important to make sure they are safe to use. Our study shows that in a well-established animal model, one such product, Cerumenex, is in fact, toxic to the cells of the ear, says Dr. Daniel.

Dr. Daniel and his team studied the impact of Cerumenex on hearing. In addition, overall toxicity in the outer ear and changes in the nerve cells of the inner ear were analyzed.

Harmful effects to a number of of the cells were observed after only one dose, says Dr. Melvin Schloss co-author and MCH Director of Otolaryngology. We observed reduced hearing, severe inflammation, and lesions to the nerve cells......... Posted by: Sue      Read more         Source

January 21, 2008, 8:29 PM CT

Saline nasal wash helps improve children's cold symptoms

A saline nasal wash solution made from processed seawater appears to improve nasal symptoms and may help prevent the recurrence of respiratory infections when used by children with the common cold, as per a report in the recent issue of Archives of Otolaryngology, one of the JAMA/Archives journals.

Infections of the upper respiratory tract and sinus infections are common among children, as per background information in the article. Nasal irrigation with isotonic [balanced] saline solutions seems effective in such health conditions and is often used in a variety of indications as an adjunctive therapy, the authors write as background information in the article. Eventhough saline nasal wash is currently mentioned in several guidelines, scientific evidence of its efficacy is rather poor.

Ivo lapak, M.D., of Teaching Hospital Brno, Brno, Czech Republic, and his colleagues randomly assigned 401 children age 6 to 10 with cold or flu to two therapy groups, one receiving standard medicine and the other also receiving a nasal wash with a modified processed seawater solution. Patients were observed for a total of 12 weeks, from January to April 2006, during which health status, symptoms and medicine use were assessed at four visits over the course of the trial, the authors write. Acute illness was reviewed during the first two visits (up to three weeks), prevention during the following two visits (up to 12 weeks). The third visit, scheduled for week eight after study entry, could be conducted over the telephone......... Posted by: Sue      Read more         Source

December 4, 2007, 10:32 PM CT

Common treatments for sinus infections may not work

A comparison of common therapys for acute sinusitis that included an antibiotic and a topical steroid found neither more effective than placebo, as per a research studyin the December 5 issue of JAMA.

Acute sinusitis (sinus infection) is a common clinical problem with symptoms similar to other illnesses, and is often diagnosed and treated without clinical confirmation. Despite the clinical uncertainty as to a bacterial cause, antibiotic prescribing rates remain as high as 92 percent in the United Kingdom and 85 percent to 98 percent in the United States, as per background information in the article. Because there are no satisfactory studies of microbiological etiology from typical primary care patient practices, wide-scale overtreatment is likely occurring, the authors write. Concerns about wide-spread antibacterial use include increasing antibiotic resistance in the community. Anti-inflammatory drugs such as topical steroids are also used as a therapy and may be beneficial, but there has been limited research.

Ian G. Williamson, M.D., of the University of Southampton, England, and his colleagues conducted a double-blind randomized placebo-controlled trial to determine the effectiveness of the antibiotic amoxicillin and topical steroid budesonide in acute maxillary sinusitis (rhinosinusitis; inflammation of the nasal cavity and sinuses). The study included 240 adults with acute nonrecurrent sinusitis treated at 58 family practices between November 2001 and November 2005. Patients were randomized to 1 of 4 therapy groups: antibiotic and nasal steroid (500 mg of amoxicillin 3 times per day for 7 days and 200 g of budesonide in each nostril once per day for 10 days); placebo antibiotic and nasal steroid; antibiotic and placebo nasal steroid; placebo antibiotic and placebo nasal steroid......... Posted by: Sue      Read more         Source

November 14, 2007, 8:42 PM CT

Genes influence age-related hearing loss

Waltham, MAA new Brandeis University study of twins shows that genes play a significant role in the level of hearing loss that often appears in late middle age. The research, in the Journal of Gerontology: Medical Sciences, examined genetic and environmental factors affecting hearing loss in the frequency range of speech recognition.

This research confirms the importance of genetic factors in age-associated hearing loss, and the need for vulnerable individuals and their families to take extra care to prevent further hearing damage, said lead author Brandeis neuroscientist Arthur Wingfield.

The research suggests that middle-aged and older people with a genetic vulnerability to hearing loss should be especially careful about environmental risk factors such as harmful noise and medications whose side-effects could be detrimental to hearing.

The study examined 179 identical and 150 fraternal male twin pairs, ranging in age from 52 to 60 years, as part of the Viet Nam Era Twin Study of Aging (VETSA). About two-thirds of the hearing loss in the individual subjects better ears could be accounted for by genetic factors. In the subjects poorer ears, about one-half of the hearing loss was due to genes, the study concluded.

Wingfield, an expert on the relationship between memory performance and hearing loss in elderly adults, said that even mild hearing loss can indirectly lead to declines in cognitive performance because intellectual energy normally reserved for higher-level comprehension must be directed toward perceptual effort for accurately hearing speech......... Posted by: Sue      Read more         Source

October 31, 2007, 8:46 PM CT

Ears ringing?

Brain researchers at Johns Hopkins have discovered how cells in the developing ear make their own noise, long before the ear is able to detect sound around them. The finding, reported in this weeks Nature, helps to explain how the developing auditory system generates brain activity in the absence of sound. It also may explain why people sometimes experience tinnitus and hear sounds that seem to come from nowhere.

The research team made their discovery while studying the properties of non-nerve cells in the ears of young rats. These so-called support cells were believed to be silent bystanders not directly involved in nerve communication. However, to the scientists surprise, these cells showed robust electrical activity, similar to nerve cells. Further, this activity occurred spontaneously, without sound or any external stimulus.

Its long been thought that nerve cells that connect auditory organs to the brain need to experience sound or other nerve activity to find their way to the part of the brain responsible for processing sound, says the studys lead author, Dwight Bergles, Ph.D., an associate professor of neuroscience at Hopkins. So when we saw that these supporting cells could generate their own electrical activity, we suspected they might somehow be involved in triggering the activity mandatory for proper nerve wiring......... Posted by: Daniel      Read more         Source

October 16, 2007, 7:21 PM CT

Ear infection superbug resistant to all pediatric antibiotics

Scientists have discovered a strain of bacteria resistant to all approved drugs used to fight ear infections in children, as per an article would be published tomorrow in the Journal of the American Medical Association (JAMA). A pair of pediatricians discovered the strain because it is their standard practice to perform an uncommon procedure called tympanocentesis (ear tap) on children when several antibiotics fail to clear up their ear infections. The procedure involves puncturing the childs eardrum and draining fluid to relieve pressure and pain. Analyzing the drained fluid is the only way to describe the bacterial strain causing the infection.

Even after the ear tap and additional rounds of antibiotics, infections persisted in a small group of children in a Rochester, New York, pediatric practice, leading to ear tube surgery and, in one case, to permanent hearing loss. The physicians realized they may be dealing with a superbug and tested the children's ear tap fluid at the University of Rochester Medical Center. The tests showed that the superbug, called the 19A strain, could be killed only by an antibiotic (levofloxacin, Levaquin) approved for adults that had a warning in its label against use in children. With no other choice, they treated the children with crushed, adult-approved pills, and it worked......... Posted by: Mark      Read more         Source

October 10, 2007, 6:48 PM CT

MIT finds new hearing mechanism

MIT scientists have discovered a hearing mechanism that fundamentally changes the current understanding of inner ear function. This new mechanism could help explain the ear's remarkable ability to sense and discriminate sounds. Its discovery could eventually lead to improved systems for restoring hearing.

The research is described in the advance online issue of the Proceedings of the National Academy of Sciences the week of October 8.

MIT Professor Dennis M. Freeman, working with graduate student Roozbeh Ghaffari and research scientist Alexander J. Aranyosi, observed that the tectorial membrane, a gelatinous structure inside the cochlea of the ear, is much more important to hearing than previously thought. It can selectively pick up and transmit energy to different parts of the cochlea via a kind of wave that is different from that usually linked to hearing.

Ghaffari, the lead author of the paper, is in the Harvard-MIT Division of Health Sciences and Technology, as is Freeman. All three scientists are in MIT's Research Laboratory of Electronics. Freeman is also in MIT's Department of Electrical Engineering and Computer Science and the Massachusetts Eye and Ear Infirmary.

It has been known for over half a century that inside the cochlea sound waves are translated into up-and-down waves that travel along a structure called the basilar membrane. But the team has now observed that a different kind of wave, a traveling wave that moves from side to side, can also carry sound energy. This wave moves along the tectorial membrane, which is situated directly above the sensory hair cells that transmit sounds to the brain. This second wave mechanism is poised to play a crucial role in delivering sound signals to these hair cells......... Posted by: Sue      Read more         Source

October 8, 2007, 9:39 AM CT

Brain Center Responsible for Tinnitus

For the more than 50 million Americans who experience the phantom sounds of tinnitus -- ringing in the ears that can range from annoying to debilitating -- certain well-trained rats may be their best hope for finding relief.

Scientists at the University at Buffalo have studied the condition for more than 10 years and have developed these animal models, which can "tell" the scientists if they are experiencing tinnitus.

These researchers now have received a $2.9 million five-year grant from the National Institutes of Health to study the brain signals responsible for creating the phantom sounds, using the animal models, and to test potential therapies to quiet the noise.

The research will take place at the Center for Hearing and Deafness, part of the Department of Communicative Disorders and Sciences in the university's College of Arts and Sciences. Richard Salvi, Ph.D., director of the center, is principal investigator. Researchers from UB's Department of Nuclear Medicine and from Roswell Park Cancer Institute in Buffalo are major collaborators on portions of the project.

Tinnitus is caused by continued exposure to loud noise, by normal aging and, to a much lesser extent, as a side effect of taking certain anti-cancer drugs. It is a major concern in the military: 30 percent of Iraq and Afghanistan combat veterans suffer from the condition......... Posted by: Sue      Read more         Source

September 6, 2007, 9:37 PM CT

developing new method for hearing loss assessment

A Purdue University researcher is working on a new technique to diagnose hearing loss in a way that more accurately reflects real-world situations.

"The traditional way to assess speech understanding in people with hearing loss is to put them in a quiet room and ask them to repeat words produced by one person they can't see," said Karen Iler Kirk, a professor of speech, language and hearing sciences. "The goal of our research is to develop new tests that reflect more natural listening situations with visual cues, different background noises, voice quality, dialects and speaking rates. This is a more accurate way to predict how people perceive speech in the real world and, therefore, can help us determine appropriate treatment and interventions, such as cochlear implants.

"The better the diagnostic tool we have to make such decisions, the better we can serve our patients".

Kirk received a $2.8 million grant from the National Institute on Deafness and Other Communication Disorders for the five-year project to develop two new audiovisual and multi-talker sentence tests that expand upon the traditional spoken word recognition format that has been used since the 1950s. One test is for adults and the other for children. More than 1,000 people ages 4-65 will participate in the study......... Posted by: Sue      Read more         Source

July 31, 2007, 9:44 PM CT

Research Focuses On Vocal Cords

Damaged or diseased vocal cords can forever change and even silence the voices we love, from a family member's to a famous personality's.

Julie Andrews, who starred in such classics as The Sound of Music, is among the professional singers who have undergone surgery to remove callus-like growths that can form from overuse of these two small, stretchy bands of tissue housed in the larynx, or voice box. Sadly, Andrews may never fully recover her singing voice after surgery on her vocal cords in 1997.

Engineering pliable, new vocal cord tissue to replace scarred, rigid tissue in these petite, yet powerful organs is the goal of a new University of Delaware research project. It is funded by a five-year, $1.8 million grant from the National Institutes of Health's National Institute on Deafness and Other Communication Disorders.

Xinqiao Jia, UD assistant professor of materials science and engineering, is leading the project. Jia's research focuses on developing intelligent biomaterials that closely mimic the molecular composition, mechanical responsiveness and nanoscale organization of natural extracellular matrices--the structural materials that serve as scaffolding for cells. These novel biomaterials, combined with defined biophysical cues and biological factors, are being used for functional tissue regeneration......... Posted by: Sue      Read more         Source

July 25, 2007, 10:23 PM CT

Improving Accuracy Of Thyroid Hormone Testing

Scientists at Georgetown University Medical Center have developed a fast and accurate way to measure a major hormone released by the thyroid gland ? an advance they say may help in the therapy of a number of women who have overactive or underactive thyroid glands.

As per the American Association of Clinical Endocrinologists, approximately 27 million Americans have thyroid glands that produce too little of the hormone, thyroxine, a condition known as hypothyroidism, or else the gland produces too much, known as hyperthyroidism. Thyroxine regulates the body's metabolism, and hypothyroidism, linked to fatigue and weight gain, is much more common than hyperthyroidism, characterized by weight loss. More than eight out of 10 patients with thyroid disease are women, and nearly one out of 50 women in the United States is diagnosed with hypothyroidism during pregnancy.

In order to treat these conditions, physicians need to know how much synthetic thyroxine to either give patients or how much natural hormone should be blocked, and there have long been concerns that the common "immunoassay" test now in use worldwide is neither specific nor very accurate. To date, the immunoassay test has been used to measure those levels in women known to have abnormal levels of thyroid function based on a screening test......... Posted by: Sue      Read more         Source

July 23, 2007, 5:17 PM CT

After Implant Of Cochlear Device

Cochlear implantselectronic devices inserted surgically in the ear to allow deaf people to hearmay restore normal auditory pathways in the brain even after a number of years of deafness.

The results imply that the brain can reorganize sound processing centers or press into service latent ones based on sound stimulation. Jeanne Guiraud, PhD, and his colleagues at the University of Lyon, Edouard Herriot University Hospital, and Advanced Bionics, a firm that makes cochlear implants, worked with deaf subjects from 16 to 74 years old and observed that younger subjects and those with a shorter history of deafness showed changes that mirrored patterns in people with normal hearing more closely. The results were reported in the July 18 Journal of Neuroscience

"The results imply a restoration to some extent of the normal organization through the use of the cochlear implant, says Manuel Don, PhD, of the House Ear Institute in Los Angeles. They also claim to find ties between the degree of restored organization and a hearing task. Such ties are of enormous importance in evaluating cochlear implant benefits. Don was not involved in this study.

Guiraud and her team studied 13 profoundly deaf adults who had received cochlear implants, on average, eight months before the study. Electrical stimulation to the ear allowed the team to locate where in the brains auditory cortex various frequencies were processed and come up with a map for these tones. Their results demonstrated that in people who had cochlear implants for at least three months, normal frequency organization was somewhat restored......... Posted by: Sue      Read more         Source

July 16, 2007, 10:19 PM CT

Reanimating Paralyzed Faces

A surgical technique known as temporalis tendon transfer, in conjunction with intense physical treatment before and after surgery, may help reanimate the features of those with facial paralysis, as per a report in the July/recent issue of Archives of Facial Plastic Surgery, one of the JAMA/Archives journals.

The rehabilitation of facial paralysis is one of the greatest challenges faced by reconstructive surgeons today, the authors write as background information in the article. It is an unfortunate fact that there is no ideal procedure that leads to the return of fully normal facial function. Furthermore, every case of facial paralysis is different in the cause of the paralysis, the degree and location of the paralysis and the resulting condition of the facial musculature and surrounding soft tissue envelope. A number of patients have excessive movement in some areas of the face and no movement in others; as a result, surgeons treating this condition must be able to perform multiple types of procedures and understand the underlying neurologic dysfunction.

Patrick J. Byrne, M.D., and his colleagues at The Johns Hopkins University School of Medicine, Baltimore, report the results of seven facial paralysis patients treated with temporalis tendon transfer. This technique typically involves an incision beginning at the ear and ending 3 to 4 centimeters into the hairline at the temple. The temporalis muscle, a fan-shaped muscle on the side of the head, is cut at the point that it connects to the jawbone and released from the tissue surrounding it. Then, it is stretched to the point where the muscles of the mouth join together. The tendon that previously connected the temporalis muscle to the jawbone is cut free and then stretched horizontally for 3 to 4 centimeters; it is sutured to the surrounding muscles and deep skin tissue. Physical treatment to retrain facial muscles begins before the surgery and continues beginning seven days after the procedure......... Posted by: Daniel      Read more         Source

July 16, 2007, 10:17 PM CT

No Change InTaste After Tonsil Removal

In a small study of patients undergoing tonsillectomy, or removal of the tonsils, none reported an ongoing dysfunction in their sense of taste following the procedure, as per a report in the recent issue of Archives of OtolaryngologyHead & Neck Surgery, one of the JAMA/Archives journals.

Together with the sense of smell and nerve impulses in the mouth, the sense of taste contributes considerably to flavor perception during eating and drinking and thus plays a major role in the enjoyment of foods and beverages, as per background information in the article. The sense of taste shows little deterioration during aging but can be weakened by disease or medications. Accidental nerve damage during some medical procedures, including radiation therapy, middle ear surgery, dental or oral surgery or tonsillectomy, also can cause taste dysfunction.

Christian A. Mueller, M.D., of the University of Vienna, Austria, and his colleagues asked 65 tonsillectomy patients (42 females, 23 males; average age 28) to rate their own sense of smell and taste before surgery on a scale of zero to 100, where zero is no sense of taste or smell and 100 is an excellent sense of taste and smell. Taste function and sensitivity also was assessed one day before surgery with gustatory testing, during which taste strips for four concentrations of sweet, sour, salty and bitter were applied to both sides of the front and back areas of the tongue. Between 64 and 173 days after surgery, patients were asked to report any changes to their sense of taste or smell and again asked to rate them from zero to 100. Gustatory testing waccording toformed again on 32 patients......... Posted by: Sue      Read more         Source

June 7, 2007, 7:34 PM CT

Cochlear Implant Restores Hearing

Scientists at Georgetown University Medical Center and the National Institutes of Health (NIH) have, for the first time, used a "bionic" ear to restore hearing in a patient with von Hippel-Lindau disease. They say this advance offers new hope for individuals with the rare disorder, which can produce non-cancerous tumors in ears, as well as in the eyes, brain, and kidneys.

The advance was possible, scientists say, because their years of research into the disease showed that these tumors do not affect the cochlear nerve necessary for receipt of sound in the brain. The device they used is known as a cochlear implant, which stimulates the cochlear nerve with electrical impulses. It is predominately used to treat the deaf.

"Based on our understanding of how these tumors affect the inner ear, we felt that a cochlear implant could work, and it did," said the study's lead author, H. Jeffrey Kim, M.D., an assistant professor in the Department of Otolaryngology--Head and Neck Surgery, and a part-time investigator at the NIH, where the surgery waccording toformed. Two years after the surgery, the implant has significantly improved the quality of life of the patient, he said.

Based on this successful surgery, which was published as a case report in the recent issue of the journal Otology & Neurology, patients with von Hippel-Lindau disease with hearing loss may be now be candidates for a cochlear implant, Kim said. The disease, caused by inheritance of a mutated tumor suppressor gene, occurs in 1 out of 36,000 live births, and about 30 percent of these patients develop tumors in their ears--often in both. To date, the only option to help control these tumors is repeated surgery, which is often not successful, he said. Loss of hearing is sudden, and hearing aids don't help, Kim said......... Posted by: Sue      Read more         Source

March 27, 2007, 9:02 PM CT

One membrane, many frequencies

Modern hearing aids, though quite sophisticated, still do not faithfully reproduce sound as hearing people perceive it. New findings at the Weizmann Institute of Science shed light on a crucial mechanism for discerning different sound frequencies and thus may have implications for the design of better hearing aids.

Research by Dr. Itay Rousso of the Weizmann Institutes Structural Biology Department, which recently appeared in the Proceedings of the National Academy of Sciences (PNAS), suggests that a thin structure in the inner ear called the tectorial membrane responds to different frequencies. This membrane communicates between the outer hair cells (which amplify sound in the form of mechanical vibrations) and the inner hair cells (which convert these mechanical vibrations to electrical signals and pass them on to the brain via the auditory nerve). If certain genes for this membrane are missing or damaged, total deafness ensues.

Rousso and research student Rachel Gueta, together with scientists at the Ben-Gurion University of the Negev, wanted to explore the mechanical properties of the tectorial membrane. Using an atomic force microscope, which probes surfaces with a fine microscopic needle, they tested the resistance of the gel-like membrane at various points to assess precisely how rigid or flexible it was. To their surprise, the researchers observed that the level of rigidity varies significantly along the length of the membrane: One end of the membrane can be up to ten times more rigid than the other......... Posted by: Sue      Read more         Source

March 22, 2007, 10:37 PM CT

Viral enzyme recruited in fight against ear infection

Parents might one day give their children a weekly therapy with a nasal spray of virus enzymes to prevent them from getting a severe middle ear infection, based on results of a study done in mice by researchers from St. Jude Children's Research Hospital and The Rockefeller University in New York. Such a therapy would kill the disease-causing bacteria without the use of antibiotics, thereby avoiding the problem of antibiotic resistance. A report on this study appears in the recent issue of the online journal "PLoS Pathogens."

Middle ear infection, also called acute otitis media, is an inflammation of the middle ear space that can cause pain, fever, irritability, lack of appetite and vomiting. The middle ear is the space just before the eardrum. About half of all children carry the bacteria that cause acute otitis media, which migrate from the nose and throat to the middle ear after an initial influenza virus infection paves the way.

The researchers based their therapy on the ability of viruses called phages to break out of bacteria they infect by using a special enzyme to destroy the cell walls. Phages infect bacteria in a way that is similar to how viruses infect animal cells. Once inside, the virus hijacks the cells biochemical machinery and forces it to make a number of copies of the virus. After the new crop of viruses is made, a viral enzyme breaks apart the infected bacterial cell wall and allows the new viruses to escape and infect additional cells......... Posted by: Sue      Read more         Source

March 13, 2007, 10:20 PM CT

why we smell better when we sniff?

Unlike most of our sensory systems that detect only one type of stimuli, our sense of smell works double duty, detecting both chemical and mechanical stimuli to improve how we smell, as per University of Pennsylvania School of Medicine scientists in the recent issue of Nature Neuroscience.

This finding, plus the fact that both types of stimuli produce reaction in olfactory nerve cells, which control how our brain perceives what we smell, explains why we sniff to smell something, and why our sense of smell is synchronized with inhaling.

"The driving force for such synchronization remained a mystery for more than 50 years," says senior author Minghong Ma, PhD, Assistant Professor of Neuroscience. "These results help us understand how the mammalian olfactory system encodes and decodes odor information in the environment".

Scientists tested two different types of stimulation on olfactory neurons in mice: chemical stimuli, such as those used in making perfumes that have almond-like and banana-like scents, and mechanical stimuli, that is pressure carried by air flow to the nostrils while breathing.

The group did this first by puffing a chemical stimulus into the nose. As expected, this produced a reaction in the olfactory neurons, the primary sensory neurons in the nose that perceive odors. Scientists then puffed a solution without the chemical stimuli into the mouse's nose. This also produced a similar, but smaller reaction in the olfactory neurons. By decreasing pressure of the non-odor solution, they also observed that the reaction in the olfactory neurons was less, confirming that it was sensitive to mechanical stimulation......... Posted by: Sue      Read more         Source

March 13, 2007, 9:41 PM CT

Jet Engines Solve the Mysteries of the Voice

Eventhough researchers know about basic voice production-the two "vocal folds" in the larynx vibrate and pulsate airflow from the lungs-the larynx is one of the body's least understood organs.

Sound produced by vocal-fold vibration has been extensively researched, but the specifics of how airflow actually affects sound have not been shown using an animal model-until now.

Vortices, or areas of rotational motion that look like smoke rings, produce sound in jet engines. New research from the University of Cincinnati (UC) uses methods developed from the study of jet noise to identify similar vortices in an animal model.

Sid Khosla, MD, lead author of the study, says vortices may help explain why individual voices are different and can have a different richness and quality to their sound.

"If vortices didn't affect sound production, the voice would sound mechanical," says Khosla, assistant professor of otolaryngology. "The vortices can produce sound by many mechanisms. This complexity produces a sound that makes my voice different from yours."

Khosla and his team report their findings in the March edition of the Annals of Otology, Rhinology and Laryngology.

"Understanding how airflow patterns affect sound in a jet engine (aeroacoustics) helps us determine how we can reduce jet noise," says coauthor Ephraim Gutmark, PhD, a UC professor of aerospace engineering. "We can apply the same physical understanding of aeroacoustics to study normal and abnormal voice"......... Posted by: Sue      Read more         Source

March 12, 2007, 9:25 PM CT

Music Training 'Tunes' Human Auditory System

A newly published study by Northwestern University scientists suggests that Mom was right when she insisted that you continue music lessons -- even after it was clear that a professional music career was not in your future.

The study, which will appear in the recent issue of Nature Neuroscience, is the first to provide concrete evidence that playing a musical instrument significantly enhances the brainstems sensitivity to speech sounds. This finding has broad implications because it applies to sound encoding skills involved not only in music but also in language.

The findings indicate that experience with music at a young age in effect can "fine-tune" the brain's auditory system. "Increasing music experience appears to benefit all children -- whether musically exceptional or not -- in a wide range of learning activities," says Nina Kraus, director of Northwestern's Auditory Neuroscience Laboratory and senior author of the study.

"Our findings underscore the pervasive impact of musical training on neurological development. Yet music classes are often among the first to be cut when school budgets get tight. That's a mistake," says Kraus, Hugh Knowles Professor of Neurobiology and Physiology and professor of communication sciences and disorders.

"Our study is the first to ask whether enhancing the sound environment -- in this case with musical training -- will positively affect the way an individual encodes sound even at a level as basic as the brainstem," says Patrick Wong, primary author of "Musical Experience Shapes Human Brainstem Encoding of Linguistic Pitch Patterns." An old structure from an evolutionary standpoint, the brainstem once was thought to only play a passive role in auditory processing......... Posted by: Janet      Read more         Source

February 15, 2007, 6:28 AM CT

Low-pitch Treatment For Tinnitus

For those who pumped up the volume one too a number of times, UC Irvine scientists may have found a therapy for the hearing damage loud music can cause.

Fan-Gang Zeng and his colleagues have identified an effective way to treat the symptoms of tinnitus, a form of hearing damage typically marked by high-pitched ringing that torments more than 60 million Americans. A low-pitched sound, the scientists discovered, applied by a simple MP3 player suppressed and provided temporary relief from the high-pitch ringing tone linked to the disorder.

Tinnitus is caused by injury, infection or the repeated bombast of loud sound, and can appear in one or both ears. It's no coincidence that a number of rock musicians, and their fans, suffer from it. Eventhough known for its high-pitched ringing, tinnitus is an internal noise that varies in its pitch and frequency. Some therapys exist, but none are consistently effective.

Zeng presented his study Feb. 13 at the Middle Winter Research Conference for Otolaryngology in Denver.

"Tinnitus is one of the most common hearing disorders in the world, but very little is understood about why it occurs or how to treat it," said Zeng, a professor of otolaryngology, biomedical engineering, cognitive sciences, and anatomy and neurobiology. "We are very pleased and surprised by the success of this treatment, and hopefully with further testing it will provide needed relief to the millions who suffer from tinnitus"......... Posted by: Sue      Read more         Source

November 6, 2006, 7:53 PM CT

Most Ear Infections Host Both Bacteria And Viruses

Ear infections are among the most common diseases seen in pediatric practice. They have generally been considered bacterial diseases and are therefore commonly treated with antibiotics. New research, reported in the December 15 issue of Clinical Infectious Diseases and currently available online, provides evidence that viruses are found in a great a number of ear infection cases and may complicate therapy.

The scientists used a variety of laboratory techniques to identify the pathogen that caused ear infections, known clinically as acute otitis media (AOM), in 79 young children. They found bacteria in 92 percent of the cases, viruses in 70 percent, and both bacteria and viruses in 66 percent.

As per Aino Ruohola, MD, PhD, from the Turku University Hospital in Finland and lead author of the study, "the major finding of the study is that acute otitis media is a coinfection of bacteria and viruses in the great majority of children. This is actually logical since acute otitis media is virtually always connected to viral respiratory infection".

Antibiotics, which are effective against the bacteria that cause AOM, have no effect on the viruses found in AOM infections. Therefore, the standard therapy for AOM--antibiotics--can be, at best, partially effective in the majority of cases. "Based on this and prior research," said Dr. Ruohola, "it is possible that viruses cause a considerable proportion of clinical therapy failures. Thus, in these cases a new antibiotic is not necessarily the best choice eventhough bacteria resistant to common antibiotics are wide-spread."........

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