A Population-Based, Nationwide Longitudinal Study of Bipolar Disorder With Incident Dementia in Taiwan.

OBJECTIVE: Affective disorders are associated with increased risk of dementia, yet most studies focus on the association of major depressive disorder or depressive episodes of bipolar disorder with increased dementia risk. The association of manic/mixed episodes of bipolar disorder with increased dementia risk is unclear. PARTICIPANTS: Between January 1, 2001 and December 31, 2009, 20,535 individuals aged 45-80 years with bipolar disorder and 82,140 age- and sex-matched comparisons were enrolled and followed up to December 2011 in Taiwan. Those who developed dementia (ICD-9-CM codes: 290.0-290.4, 294.1-294.2, and 331.0-331.2) during the follow-up period were identified. DESIGN AND METHODS: Cox proportional hazards models were used to examine the relationship between manic/mixed/depressive episodes of bipolar disorder and incident dementia. We also assessed the association between the frequency of psychiatric admissions (total, manic/mixed, and depressive episodes per year) for bipolar disorder and dementia risk. RESULTS: Bipolar disorder was associated with increased risk of incident dementia (hazard ratio [HR]: 7.52, 95% confidence interval [CI]: 6.86-8.25). Greater frequency of manic/mixed (>2/year: HR: 4.50, 3.50-5.79; 1-2/year: HR: 3.17, 2.31-4.36) and depressive episodes (>2/year: HR: 7.84, 5.93-10.36; 1-2/year: HR: 2.93, 2.05-4.19) were associated with increased risk of incident dementia. CONCLUSIONS: Not only depressive episode of bipolar disorder, but manic/mixed episodes of bipolar play a role as a risk factor of incident dementia, especially for those patients with more than two manic/mixed episodes per year. These findings remind the clinicians the importance of preventing the relapse of bipolar disorder for the potential subsequent cognitive decline and disease.

Amplified surface plasmon resonance immunosensor for interferon-gamma based on a streptavidin-incorporated aptamer.

Interferon-gamma (IFN-γ) is associated with susceptibility to tuberculosis, which is a major public health problem worldwide. Although significant progress has been made with regard to the design of enzyme immunoassays for IFN-γ, this assay is still labor-intensive and time-consuming. We therefore designed a DNA aptamer hairpin structure for the detection of IFN-γ with high sensitivity and selectivity. A streptavidin DNA aptamer was incorporated into the IFN-γ binding aptamer probe for the amplified detection of the target molecules. Initially, the probe remained in the inactive configuration. The addition of IFN-γ induced the rearrangement of the aptamer structure, allowing the self-assembly of the active streptavidin aptamer conformation for the streptavidin molecular recognition. Under optimized conditions, the detection limit was determined to be 33 pM, with a dynamic range from 0.3 to 333 nM, both of which were superior to those of corresponding optical sensors. Because combined aptamers are composed of nucleic acids, this optical aptasensor provided the advantages of high sensitivity, simplicity, reusability, and no further labeling or sample pre-treatment.

Surface plasmon resonance detection of silver ions and cysteine using DNA intercalator-based amplification.

We report the development of a surface plasmon resonance sensor based on the silver ion (Ag(+))-induced conformational change of a cytosine-rich, single-stranded DNA for the detection of Ag(+) and cysteine (Cys) in aqueous solutions. In the free state, single-stranded oligonucleotides fold into double-helical structures through the addition of Ag(+) to cytosine­cytosine (C­C) mismatches. However, in the presence of Cys, which competitively binds to Ag(+), the formation of the C­Ag(+)­C assembly is inhibited, resulting in free-state, single-stranded oligonucleotides. To enhance sensitivity, the DNA intercalator, daunorubicin, was employed to achieve signal enhancement. The detection limit for Ag(+) was 10 nM with a measurement range of 50­2,000 nM, and the detection limit for Cys was 50 nM with a measurement range of 50­2,000 nM. This simple assay was also used to individually determine the spiked Ag(+) concentration in water samples and Cys concentrations in biological fluid samples.

An amplified surface plasmon resonance "turn-on" sensor for mercury ion using gold nanoparticles.

Inorganic mercury ion (Hg(2+)) has been shown to coordinate to DNA duplexes that feature thymine-thymine (T-T) base pair mismatches. This observation suggests that an Hg(2+)-induced conformational change in a single-stranded DNA molecule can be used to detect aqueous Hg(2+). Here, we have developed an analytical method using surface plasmon resonance (SPR) to develop a highly selective and sensitive detection technique for Hg(2+) that takes advantage of T-Hg(2+)-T coordination chemistry. The general concept used in this approach is that the "turn-on" reaction of a hairpin probe via coordination of Hg(2+) by the T-T base pair results in a substantial increase in the SPR response, followed by specific hybridization with a gold nanoparticle probe to amplify the sensor performance. Meanwhile, the limit of detection is 1 nM, which is lower than other recently developed techniques. A linear correlation is observed between the measured SPR reflectivity and the logarithm of the Hg(2+) concentration over the concentration range of 5-5000 nM. Additionally, the SPR system provides high selectivity for Hg(2+) in the presence of other divalent metal ions up to micromolar concentration levels. The proposed approach is also successfully utilized for the determination of Hg(2+) in water samples.