The link between hair disorders and susceptibility to dental caries

Dentistry_Dermatology_Dental Hygiene_Infectious DiseaseAt the 93rd General Session and Exhibition of the International Association for Dental Research, researcher Olivier Duverger, National Institutes of Health-National Institute of Neurological Disorders and Stroke, Bethesda, Md., USA, presented a study titled “Hair Keratins as Structural Organic Components of Mature Enamel: The Link Between Hair Disorders and Susceptibility to Dental Caries.” The IADR General Session held in conjunction with the 44th Annual Meeting of the American Association for Dental Research and the 39th Annual Meeting of the Canadian Association for Dental Research.Hair and teeth are ectodermal appendages that share common developmental mechanisms. However, the major structural components making up hair and teeth are very distinct. The hair shaft is essentially made of keratin filaments that are highly cross-linked. Tooth enamel matrix is primarily composed of enamel proteins (amelogenin, ameloblastin) that are degraded and replaced by minerals during enamel maturation. Fully mineralized enamel contains a small fraction of cross-linked organic material that has not been fully characterized. In this study, researchers assessed the presence and functionality of a specific set of hair keratins in this organic fraction of enamel.

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Infants’ gut bacteria linked to food sensitization

sleeping-infantA recent study reveals new clues on how changes to the mix of bacteria in the gut of young babies may offer a way to predict the future development of food allergy or asthma.The finding is the work of researchers from the University of Alberta and University of Manitoba in Canada and is published in the journal Clinical & Experimental Allergy.The team found that infants with less diverse gut bacteria at 3 months were more likely to show sensitivity to certain foods like egg, milk and peanut by the age of 12 months.Two types of bacteria were of particular significance:Enterobacteriaceae and Bacteroidaceae. The researchers found infants that developed food sensitization had different levels of these bacteria compared with those that did not.The team used results of DNA analysis to classify bacteria in the stools of infants collected at 3 months and 12 months of age. From this, they could see which bacteria present early in life predicted the development of food sensitization at 1 year – as measured by a skin reaction test.
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Can a bacterial virus from Jerusalem sewage prevent root canal infections?

Dentistry_Infectious DiseaseScientists turn the tables on drug-resistant bacteria by infecting them with bacteriophages (bacterial viruses)

Every year, drug-resistant infections kill more than 50,000 people across Europe and the United States, and hundreds of thousands more around the world. According to the Review on Antimicrobial Resistance commissioned by the UK Prime Minister, failing to address the growing problem of drug-resistant infections could cause 10 million deaths a year and cost up to $100 trillion USD by 2050. (See Antimicrobial Resistance: Tackling a Crisis for the Health and Wealth of Nations)Now, researchers from the Hebrew University of Jerusalem’s Faculty of Dental Medicine propose a way to turn the tables on harmful bacteria that infect humans, by infecting them with tiny viruses called bacteriophages. In a strange twist, one such virus, cultivated from Jerusalem sewage, may help prevent infections following dental procedures.Just a few decades ago, antibiotics were considered wonder drugs. Ironically, because they worked so well, they were used too often, leading to the rise of drug-resistant bacteria. These untreatable pathogens evolved mutations enabling them to resist the antibiotics that doctors prescribe to fight them.One such pathogen is Enterococcus faecalis, a bacterium inhabiting the gastrointestinal tracts of humans. This life-threatening pathogen causes diseases ranging fromendocarditis (a potentially fatal heart infection) to bacteremia (harmful bacteria in the bloodstream), as well urinary tract infection, meningitis, and post-treatment root canal infections.

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Recent gut and urinary tract infections may curb risk of rheumatoid arthritis

Urology_Infectious DiseaseRecent gut and urinary tract infections may curb the risk of developing rheumatoid arthritis, suggests research published online in the Annals of the Rheumatic Diseases.One possible explanation could lie in the way in which these infections alter the types of bacteria resident in the gut (microbiome), say the researchers.They set out to look at the impact of different types of infection on the risk of developing rheumatoid arthritis in almost 6500 people living in south and central Sweden.Some 2831 of the entire sample had been newly diagnosed with rheumatoid arthritis between 1996 and 2009. The remaining 3570, who were randomly selected from the population, were healthy, but matched for age, sex, and area of residence with the patients.All participants were asked whether they had had any gut, urinary tract, or genital infections in the preceding two years. They were also asked if they had had prostatitis (inflamed prostate), or antibiotic treatment for sinusitis, tonsillitis/other throat infection, or pneumonia during this time.

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Study reveals how listeria breaches the placenta

GastroeneterologyA gut bacterium called Listeria (Listeria monocytogenes), which is often found in soft cheese, is known to present a risk to pregnant women. Listeria uses distinct tactics to breach the intestine and the placenta, using a protein called phosphoinositide-3 kinase (PI3-K), according to a study published in The Journal of Experimental Medicine.

Listeria has two proteins that help it cross mucosal tissue barriers. Both proteins, called internalins A and B, attach to tissue receptors and are needed for Listeria to invade the placenta, but protein A alone can propel Listeria across the intestine. What underlies these differences has remained unknown. For more information read here



Alterations in fatty acid synthesis linked to sepsis inflammation

Emergency Medicine_Infectious Disease

Sepsis is a leading cause of death for patients in intensive care units.

The excessive systemic inflammation in individuals with sepsis damages organs and can lead to death.

Therapeutic options for sepsis are limited and the factors that promote this excessive response to infection are poorly understood.

A new study in the Journal of Clinical Investigation identifies a metabolic pathway that underlies sepsis inflammation.

Augustine Choi and colleagues at Weill Cornell Medical College found that a mitochondrial uncoupling protein, UCP2, is elevated in patients with sepsis.

In mouse model of sepsis, lack of this protein improved survival.

The authors determined that expression of UCP2 induces fatty acid synthesis, which in turn activates inflammatory pathways.

The results of this study suggest that UCP2 should be further explored as a potential therapeutic target for inflammatory diseases.

Title: UCP2-induced fatty acid synthase promotes NLRP3 inflammasome activation during sepsis

Adapted by MNT from original media release


Could HIV make hearing worse?

Infectious Disease_Otolaryngology

Human immunodeficiency virus can be incredibly debilitating, leaving individuals vulnerable to serious illnesses. On top of this, researchers have now suggested that adults with the virus have poorer low- and high-frequency hearing than adults who do not have the disease.


The findings, published in JAMA Otolaryngology – Head and Neck Surgery, come after an evaluation of the pure-tone hearing thresholds of men and women, some with the human immunodeficiency virus (HIV+) and some without (HIV-).

HIV is a virus that impairs the immune system, making people with the condition increasingly susceptible to infection and disease. There is currently no cure, but HIV+ individuals can be given a combination of medicines called highly active antiretroviral therapy (HAART) to slow the spread of the virus.

Since HAART became widely used, there has been very little investigation into the relationship between HIV infection and hearing loss, according to the study authors.

“There have been limited data obtained on the effects of HIV-related medication use on hearing loss,” they write, “and in the few published studies, it is difficult to attribute the increases in hearing loss specifically to HIV medication use rather than age or cumulative noise exposure.”

Dr. Peter Torre III, of San Diego State University in California, and colleagues set out to determine whether HIV disease variables and HAART are associated with changes to pure-tone threshold levels – the softest sounds audible to individuals for the majority of the time.

Evaluating the pure-tone threshold averages

For the study, the researchers assessed the hearing of 262 men with an average age of 57 and 134 women with an average age of 48.

Of the men, 117 (44.7%) were HIV+, and of the women, 105 (78.4%) were HIV+. Participants were taken from the sites of the Multicenter AIDS Cohort Study and the Women’s Interagency HIV Study.

Pure-tone threshold levels were measured in both ears in a sound-treated room. The researchers tested a wide range of frequencies, from 250 Hz to 8,000 Hz.

The researchers discovered that high- and low-frequency pure tone averages (LPTA and HPTA) were significantly higher in the better ears of the HIV+ participants, indicating that their hearing was poorer than the HIV- participants.

Even after adjusting the findings for current CD4+ cell count, HIV viral load and long-term exposure to antiretroviral medication, the results remained the same.

“To our knowledge, this is the first study to demonstrate that HIV+ individuals have poorer hearing across the frequency range after many other factors known to affect hearing have been controlled for,” write the authors.

Poorer hearing also found in individuals with diabetes mellitus

“The participants were middle-aged,” write the authors, “so an HIV effect on LPTA was not expected, given the speculation that long-term [HAART] exposure or HIV itself contributes to premature aging.”

Although unexpected, the authors also note that hearing loss at both LPTA and HPTA has previously been observed to be more likely in adults with diabetes mellitus. “It is possible that both HIV infection and diabetes, being systemic diseases, could affect the neural function of the cochlea,” they suggest.

The study is limited by the fact that participants were only recruited from specific geographical areas, namely Baltimore, MA, and Washington, DC. For women, the ratio of HIV+ to HIV- participants was also uneven, and future studies could rectify these representational imbalances.

“Although we do not understand the mechanism of hearing loss found in our study, our results suggest that HIV+ individuals may have physiologic changes that mimic other chronic conditions that affect hearing levels,” conclude the authors.

Earlier this month, Medical News Today reported on a mouse study suggesting hearing loss could be prevented by a vitamin supplement that protects the nerves stimulating the cochlea.

Written by James McIntosh