HBsAg mutants cause increasing concern

HBsAg mutants cause increasing concern

SCIENCE AND MEDICINE T ranscendental meditation seems to decrease atherosclerosis and may lower the risk of heart attack and stroke in hypertensive ...

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SCIENCE AND MEDICINE

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ranscendental meditation seems to decrease atherosclerosis and may lower the risk of heart attack and stroke in hypertensive adults, report US researchers. “We’re excited because it’s the first time that a stress-reduction approach alone—without changes in diet, exercise, drugs, or surgery —has been shown to regress this disease”, says co-author Robert Schneider (Maharishi University of Management, Fairfield, IA, USA). In the study, a group of hypertensive African Americans received training in transcendental meditation—the repetition of a sound (mantra) to achieve a state of “restful alertness”—or conventional heart-disease education. After 6–9 months, carotid intima–media thickness increased by 0·054 mm in the education group, but decreased by 0·098 mm in the meditation group; this reduction was similar to that achieved by lipid-lowering drugs and extensive lifestyle changes (Stroke 2000; 31: 568–73). “Some people say that all relaxation methods are equally effective, but we know from related studies that this is not true”, notes Schneider. “The type of stressreduction technique is critical.” Limited funding led to fewer people (60 of 138) completing the meditation programme than expected, he adds. But this high attrition rate may not be unusual. A review of 20 behavioural-medicine programmes by Michael Addis and Mary Davis (Clark University, Worcester, MA, USA) indicates that about one in three participants drop out before completing such programmes (Ann Behav Med 2000; 21: 339–49). “A large percentage of people either don’t get the services or drop out early on and don’t benefit much”, says Addis. But Davis warns that the drop-out rate may be misinterpreted, because some people gain sufficient self-management skills without completing an entire programme. “Just because someone doesn’t come back after several sessions doesn’t mean they didn’t benefit. These strategies might be working and people may be using them, so don’t count them out”, she concludes. Marilynn Larkin

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Periodontal problems in Down’s syndrome he severe periodontal inflammation often seen in children with Down’s syndrome is directly linked to increased concentrations of oral bacteria, say researchers at Osaka University, Japan. Several factors have been implicated in the periodontal problems of patients with Down’s syndrome, including poor oral hygiene, an impaired immune system, fragile periodontal tissue, and early senescence. However, little is known about the oral flora in these patients. Atsuo Amano and colleagues used PCR and DNA probe techniques to study oral bacterial populations in subgingival plaque samples from 60 children with Down’s syndrome and 60 age-matched controls. Only patients with good oral hygiene were admitted to the study. Nevertheless, several bacterial species —eg, Porphyromonas gingivalis, which

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is known to cause gingival inflammation—occurred only in the Down’s syndrome group; other periodontal pathogens were found at higher concentrations in this group of children. The numbers of bacterial species increased with age, and the severity of the periodontal inflammation was directly related to increased concentrations of pathogens (J Periodontol 2000; 71: 250–56). “This study is very interesting”, says Raman Bedi, director of the WHO Collaborating Centre for Disability, Culture and Oral Health. “But it is early days yet, and the sample size is quite small. What would be useful now is a longitudinal study, since bacteria in the mouth are very transitory. Such a study might lead to better prevention strategies and treatments for these patients.” Sue Silver

HBsAg mutants cause increasing concern nated individuals in several other epatitis B virus (HBV) vaccinacountries, he said, and an intrafamiltion programmes have reduced ial analysis indicates that it can be carrier rates and acute morbidity in transmitted vertically or horizontally endemic regions of the world, and to immune individuals and to carriers have an excellent safety track of wild-type HBV. record, explained Lindsay Martinez, Although mutarepresentative of the tions in the HBV Director-General of DNA polymerase WHO, at the Interhave previously national Congress been detected after on Viral Hepatitis long-term antiviral held in Singapore therapy with nucleo(Feb 16–19). side analogues, But now viruses mutations in HBsAg with mutations in are also now being the “a” determinant found. Viruses carof the surface antirying these mutagen (HBsAg) are tions may not be being found in detected with stanvaccinees, carrier dard immuno-based populations after A changing target for vaccination assays for HBV, antiviral nucleoside warned Arie Zuckerman (Royal Free drug therapy, and liver transplant Hospital, London, UK), and this recipients treated with hepatitis B could lead to HBV being undetected immunoglobulin, reported Stephen in blood supplies. Hopefully, he said, Locarnini of the Victorian Infectious this problem will be solved by Diseases Reference Laboratory, improving existing detection kits and North Melbourne, Australia, and by implementing new technology Chong Jin Oon of Singapore General such as DNA chips. Hospital. Worryingly, the neutralisIn the light of these and other finding antibodies raised by vaccination ings, delegates closed the congress by may not be effective against these calling for epidemiological monitormutants. ing of HBsAg mutants to be continAccording to Oon, the Gly145Arg ued and for further assessment of mutant is the most common posttheir association with liver diseases. vaccination HBsAg mutation seen in infants in Singapore. This mutant is increasingly being detected in vacciWei Ning Chen

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Meditation may reduce heart attack and stroke risk

THE LANCET • Vol 355 • March 4, 2000