Efficient Antimicrobial Effect of Alginate-Catechol/Fe2+ Coating on Hydroxyapatite toward Oral Care Application.

Reducing the formation of oral bacterial biofilms is critical to prevent common dental diseases. Though many strategies for restricting bacterial adhesion on tooth surfaces have been reported, a simple method for efficient oral bacteriostasis is still highly expected. Herein, we have proved a soft gel made of an alginate-catechol conjugate (SA-DA) and the ferrous cation (Fe2+) as an effective antibacterial coating on hydroxyapatite (HAP, a tooth model). As suggested by quartz crystal microbalance (QCM) measurements, SA-DA/Fe2+ coating possessed a high binding affinity to HAP without destruction by either immersion in artificial saliva or simulated tooth brushing. Significantly less protein (bovine serum albumin) and Streptococcus mutans (S. mutans, an oral bacterial model) could be found on HAP after coating with SA-DA/Fe2+, indicating that the prepared gel could resist well the adhesion of biofouling and microbes due to its hydrophilicity. Notably, such an antibacterial effect (around 70% S. mutans was inhibited) could be maintained for 3 d, which resulted from the extremely good stability of SA-DA/Fe2+ coating, as confirmed by QCM analysis. Our results may offer possibilities for developing applications in order to further improve oral hygiene.

Directions of Deep Brain Stimulation for Epilepsy and Parkinson's Disease.

BACKGROUND: Deep brain stimulation (DBS) is an effective treatment for movement disorders and neurological/psychiatric disorders. DBS has been approved for the control of Parkinson disease (PD) and epilepsy. OBJECTIVES: A systematic review and possible future direction of DBS system studies is performed in the open loop and closed-loop configuration on PD and epilepsy. METHODS: We searched Google Scholar database for DBS system and development. DBS search results were categorized into clinical device and research system from the open-loop and closed-loop perspectives. RESULTS: We performed literature review for DBS on PD and epilepsy in terms of system development by the open loop and closed-loop configuration. This study described development and trends for DBS in terms of electrode, recording, stimulation, and signal processing. The closed-loop DBS system raised a more attention in recent researches. CONCLUSION: We overviewed development and progress of DBS. Our results suggest that the closed-loop DBS is important for PD and epilepsy.

Molecular epidemiological study of dengue virus type 1 in Taiwan.

Taiwan has experienced several major outbreaks of dengue (DEN) virus since 1981. The predominant virus type involved has been dengue virus type one (DEN-1), which first appeared in 1987. To understand the molecular epidemiology of this virus, 15 strains of DEN-1 isolated during 1987-1991 and 1994-1995, including 11 epidemic strains, two sporadic strains, and two imported strains have been studied. Fragments of 490 nucleotides (nt) from the E/NS1 junction were amplified by reverse transcription-polymerase chain reaction and the nt sequences were determined. Of the 490 nt of the E/NS1 junction, 240 nt (nt 2282-2521) were aligned and compared. Nucleotide substitutions were found at 54 positions among 15 isolates. Most nt changes were synonymous substitutions, and only three amino acid changes were found. A total of 61 strains isolated worldwide were analyzed by the Neighbor-joining method, and separated phylogenetically into three distinct genotypes, I-III. Genotype I comprised isolates from Japan and Hawaii collected in the 1940s. Genotype II included most strains isolated from Asia in 1977-1995. Genotype III consisted of isolates from three continents in 1964-1995: Asia, the Americas, and Africa. Genotype III was divided further into two subgenotypes, IIIA and IIIB. Most recent isolates from Taiwan, except for the sporadic strain isolated in 1995, were similar genetically and have been classified as Genotype II.

Measles IgG seroprevalence prior to mass vaccination in Taiwan.

OBJECTIVES: Measles vaccine was licensed for use in Taiwan in 1968 and mass vaccination has been implemented since 1978. Serological surveys were conducted to characterize measles seroepidemiology prior to mass vaccination. METHODS: Measles IgG was quantitatively measured in 1564 serum samples collected from four populations (nationwide, urban, rural, and mountain areas) during 1974-80 with a commercial EIA kit. The nationwide samples covered age groups from 3 months to 19 years, but the other three samples only covered school-aged children. The cut-off value of seropositivity was set at 100 mIU/ml. RESULTS: In the nationwide samples, measles IgG seroprevalence decreased from 50% at 3-5 months to 13% at 6-11 months, then increased rapidly to 55% at 1-1.9 years and reached 98% at 7-7.9 years of age; this was maintained to young adulthood. In all four samples, seroprevalence also reached >97% in individuals >10 years of age. Semiquantitative analysis found that 24%(10/42) of 1-1.9-year-old children but only 4%(1/24) of 15-19-year-old adolescents had low level measles IgG (100-399 mIU/ml). In addition, the distribution of measles IgG level in 1-1.9-year-old children had two peaks at 200-399 and 1600-3199 mIU/ml, whereas only one peak at 1600-3199 mIU/ml had been found in 15-19-year-old adolescents. The median age of measles infection (i.e. 50% seroprevalence) in Taiwan was 1.4 and 2.1 years, respectively, before and after excluding individuals with measles IgG 100-399 mIU/ml that may have resulted from vaccination. CONCLUSIONS: Measles seroepidemiology in Taiwan in the 1970s seemed to be more similar to that in a developing country rather than in an industrialized country, and there was a low median age of infection.