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Diabetes and hypertension linked to cognitive decline in mid-life
SCIENCE AND MEDICINE
New vaccines for mycobacterial infections “desperately needed” he rate of new leprosy cases in India “remains disturbingly constant” and “every minute two people become sputum positive for Mycobacterium tuberculosis and one person dies”, pointed out K V Dasiklan (Lepra, India) in his opening address at the International Symposium on Mycobacterial Diseases (Calcutta, India; Jan 9–11). Mycobacterial infections including tuberculosis and leprosy, as well as M avium intracellulare complex infections in AIDS patients remain a major cause of morbidity and mortality worldwide, particularly in less-developed nations. The aim of the meeting was to discuss new approaches for
T
binding haemagglutinin protein “may play an important role in the dissemination of mycobacteria from the lungs to other tissues”, and could offer a potential target in attempts to limit systemic spread of infection. The meeting also focused on the development of effective vaccines for the developing world. “The world deperately needs a better vaccine against tuberculosis”, explains Des Collins (AgResearch, New Zealand), who called for both targeted and random mutagenesis studies to generate new vaccine candidates for in-vivo testing.
understanding the pathogenesis and control of mycobacterial infections. In his keynote lecture, Stewart Cole (Institute Pasteur, France) discussed the “numerous therapeutic and prophylactic applications” that are emerging following the sequencing of the tuberculosis and leprosy genomes. Such advances offer new targets for more effective drugs. Discussion also focused on the mechanisms by which mycobacteria interact with macrophages, a major target of infection, and the consequences of this on host immune responses and tissue damage. According to Camille Locht (Institute Pasteur, France) new evidence has emerged that the heparin-
Jon Friedland
Self-recognition located in right hemisphere, say neuroscientists elf-recognition is achieved mainly by right hemisphere processes, according to US researchers this week. “Keenan and colleagues have begun to unravel the physical foundations of consciousness itself, especially those aspects that are unique to our species”, comments Mark A Wheeler (Temple University, Philadelphia, PA, USA). The investigators studied five patients while they underwent a Wada test (in which amobarbital is injected into one of the carotid arteries to selectively anaesthetise either the left or the right hemisphere) for evaluation of surgery to treat epilepsy. During the Wada test the researchers showed the patients a photograph of a face generated by “morphing” the patient’s face with that of a famous celebrity.
“Following anaesthesia, the patient was asked which face was presented: the self face or the
Rights were not granted to include this image in electronic media. Please refer to the printed journal.
Which of the top faces was presented?
famous face”, explains Julian Keenan (Harvard Medical School, Boston, MA, USA), the lead investigator of the study. “With the right hemisphere anaesthetised, the
Julian Keenan
S
patients selected the famous face, with the left hemisphere anaesthetised the patients selected the self-face” (Nature 2001; 409: 305). If these data prove to be correct Wheeler thinks that they could help solve one of the enduring mysteries of neuropsychology, namely the role of the right prefrontal cortex. “While the left anterior cortex is critical for both language output and logical reasoning, the right side has long been the ‘silent area’, with no obvious, compelling contribution to human cognition. The assignment of self-consciousness to this region will ultimately be over-simplistic, but may also prove an important stage in motivating additional, similar experiments.” James Butcher
Diabetes and hypertension linked to cognitive decline in mid-life iddle-aged adults who have diabetes and/or high blood pressure are at increased risk for cognitive decline, report a multicentre team of US researchers. The findings should serve as a “powerful impetus” for aggressive recognition and treatment of these conditions before age 60, says lead author David Knopman (Mayo Clinic, Rochester, MN, USA). Knopman and co-workers in the atherosclerosis risk in communities study tested the cognitive abilities of 10 963 individuals, aged between 47 and 70 years, at baseline and 6-years later using standard assessment tools. The average scores for all participants
M
THE LANCET • Vol 357 • January 20, 2001
declined over the study period, but people with diabetes and/or hypertension had greater, statistically significant declines compared with participants who did not have these conditions. Diabetes was associated with a greater decline for all the particpants studied, while hypertension was a risk factor for cognitive decline only for those over age 58 (Neurology 2001; 56: 42–48). “The bottom line for clinicians is that treating these diseases aggressively in middle age is important for preventing complications later in life”, emphasises Knopman. “Individuals would not notice the small changes we observed in the
study period, but we can extrapolate to what our subjects would look like had we been able to study them after 20 years, and infer that there would be losses of mental function that would be evident to them”, he warns. Does this mean that people with diabetes or hypertension are at increased risk for Alzheimer’s disease? Although the data from this study do not permit predictions about Alzheimer disease risk, he says, “if diabetes or hypertension lead to cognitive decline—regardless of the reason—over the next 20 years, that is not a good thing.” Marilynn Larkin
203
For personal use only. Not to be reproduced without permission of The Lancet.
New vaccines for mycobacterial infections “desperately needed” he rate of new leprosy cases in India “remains disturbingly constant” and “every minute two people become sputum positive for Mycobacterium tuberculosis and one person dies”, pointed out K V Dasiklan (Lepra, India) in his opening address at the International Symposium on Mycobacterial Diseases (Calcutta, India; Jan 9–11). Mycobacterial infections including tuberculosis and leprosy, as well as M avium intracellulare complex infections in AIDS patients remain a major cause of morbidity and mortality worldwide, particularly in less-developed nations. The aim of the meeting was to discuss new approaches for
T
binding haemagglutinin protein “may play an important role in the dissemination of mycobacteria from the lungs to other tissues”, and could offer a potential target in attempts to limit systemic spread of infection. The meeting also focused on the development of effective vaccines for the developing world. “The world deperately needs a better vaccine against tuberculosis”, explains Des Collins (AgResearch, New Zealand), who called for both targeted and random mutagenesis studies to generate new vaccine candidates for in-vivo testing.
understanding the pathogenesis and control of mycobacterial infections. In his keynote lecture, Stewart Cole (Institute Pasteur, France) discussed the “numerous therapeutic and prophylactic applications” that are emerging following the sequencing of the tuberculosis and leprosy genomes. Such advances offer new targets for more effective drugs. Discussion also focused on the mechanisms by which mycobacteria interact with macrophages, a major target of infection, and the consequences of this on host immune responses and tissue damage. According to Camille Locht (Institute Pasteur, France) new evidence has emerged that the heparin-
Jon Friedland
Self-recognition located in right hemisphere, say neuroscientists elf-recognition is achieved mainly by right hemisphere processes, according to US researchers this week. “Keenan and colleagues have begun to unravel the physical foundations of consciousness itself, especially those aspects that are unique to our species”, comments Mark A Wheeler (Temple University, Philadelphia, PA, USA). The investigators studied five patients while they underwent a Wada test (in which amobarbital is injected into one of the carotid arteries to selectively anaesthetise either the left or the right hemisphere) for evaluation of surgery to treat epilepsy. During the Wada test the researchers showed the patients a photograph of a face generated by “morphing” the patient’s face with that of a famous celebrity.
“Following anaesthesia, the patient was asked which face was presented: the self face or the
Rights were not granted to include this image in electronic media. Please refer to the printed journal.
Which of the top faces was presented?
famous face”, explains Julian Keenan (Harvard Medical School, Boston, MA, USA), the lead investigator of the study. “With the right hemisphere anaesthetised, the
Julian Keenan
S
patients selected the famous face, with the left hemisphere anaesthetised the patients selected the self-face” (Nature 2001; 409: 305). If these data prove to be correct Wheeler thinks that they could help solve one of the enduring mysteries of neuropsychology, namely the role of the right prefrontal cortex. “While the left anterior cortex is critical for both language output and logical reasoning, the right side has long been the ‘silent area’, with no obvious, compelling contribution to human cognition. The assignment of self-consciousness to this region will ultimately be over-simplistic, but may also prove an important stage in motivating additional, similar experiments.” James Butcher
Diabetes and hypertension linked to cognitive decline in mid-life iddle-aged adults who have diabetes and/or high blood pressure are at increased risk for cognitive decline, report a multicentre team of US researchers. The findings should serve as a “powerful impetus” for aggressive recognition and treatment of these conditions before age 60, says lead author David Knopman (Mayo Clinic, Rochester, MN, USA). Knopman and co-workers in the atherosclerosis risk in communities study tested the cognitive abilities of 10 963 individuals, aged between 47 and 70 years, at baseline and 6-years later using standard assessment tools. The average scores for all participants
M
THE LANCET • Vol 357 • January 20, 2001
declined over the study period, but people with diabetes and/or hypertension had greater, statistically significant declines compared with participants who did not have these conditions. Diabetes was associated with a greater decline for all the particpants studied, while hypertension was a risk factor for cognitive decline only for those over age 58 (Neurology 2001; 56: 42–48). “The bottom line for clinicians is that treating these diseases aggressively in middle age is important for preventing complications later in life”, emphasises Knopman. “Individuals would not notice the small changes we observed in the
study period, but we can extrapolate to what our subjects would look like had we been able to study them after 20 years, and infer that there would be losses of mental function that would be evident to them”, he warns. Does this mean that people with diabetes or hypertension are at increased risk for Alzheimer’s disease? Although the data from this study do not permit predictions about Alzheimer disease risk, he says, “if diabetes or hypertension lead to cognitive decline—regardless of the reason—over the next 20 years, that is not a good thing.” Marilynn Larkin
203
For personal use only. Not to be reproduced without permission of The Lancet.