The pharmacokinetics of 38% silver diamine fluoride in healthy children with dental caries: a quasi-experimental study.

PURPOSE: Silver diamine fluoride (SDF) is a medication used for the arrestment of dental caries. This study aims to determine the pharmacokinetics (PK) of silver and fluoride following SDF application in healthy children with dental caries. METHODS: A total of 15 subjects, aged 4 to 10 years, with at least one cavity on a primary tooth, were recruited for this study. Urine samples were collected at baseline, first 24 h (F1) and second 24 h (F2) after SDF treatment for analysis of silver and fluoride content. Hair samples were also collected at baseline and at 7, 14, 30, 60, 75, and 90 days after SDF treatment to analyze silver content. RESULTS: Participants with under or over-collection of urine, or failure to provide urine collection were excluded for fluoride analysis. As a result, eight subjects' urine samples were eligible for fluoride analysis. Significant correlations were observed between baseline urinary fluoride levels and F1/F2 levels. Pairwise comparisons from Friedman's test showed significant differences between baseline and F1 fluoride levels. For silver analysis, 15 subjects were studied. F1 urinary silver levels were higher than baseline and F2 levels. Subsequent to SDF treatment, hair silver levels displayed fluctuations around the baseline. None of the participants reported adverse effects, and all caries teeth ceased progression within 30 days. CONCLUSIONS: The urinary fluoride levels after SDF treatment, although higher, were not clinically significant. Urinary and hair silver levels were negligible. Therefore, SDF appears safe to be used among children.

Modelling porous structures by penalty approach in the extended finite element method.

In this study, a methodology for studying porous structures was proposed. The extended finite element method (XFEM) in conjunction with a penalty approach was used to model the porous structures. The holes were considered to have very small Young's modulus, thus they could be treated as inclusions in a matrix. The level set method was applied to describe the internal boundaries of the holes. Various porous structures were investigated. A practical example of the porous structures, which was the microstructure of a trabecular bone, was examined to show the capability of the proposed methodology. The aim of the study was to demonstrate that various complicated porous structures can be modelled efficiently by the XFEM without any major modification to the existing formula.

Mutant p53 drives invasion in breast tumors through up-regulation of miR-155.

Loss of p53 function is a critical event during tumorigenesis, with half of all cancers harboring mutations within the TP53 gene. Such events frequently result in the expression of a mutated p53 protein with gain-of-function properties that drive invasion and metastasis. Here, we show that the expression of miR-155 was up-regulated by mutant p53 to drive invasion. The miR-155 host gene was directly repressed by p63, providing the molecular basis for mutant p53 to drive miR-155 expression. Significant overlap was observed between miR-155 targets and the molecular profile of mutant p53-expressing breast tumors in vivo. A search for cancer-related target genes of miR-155 revealed ZNF652, a novel zinc-finger transcriptional repressor. ZNF652 directly repressed key drivers of invasion and metastasis, such as TGFB1, TGFB2, TGFBR2, EGFR, SMAD2 and VIM. Furthermore, silencing of ZNF652 in epithelial cancer cell lines promoted invasion into matrigel. Importantly, loss of ZNF652 expression in primary breast tumors was significantly correlated with increased local invasion and defined a population of breast cancer patients with metastatic tumors. Collectively, these findings suggest that miR-155 targeted therapies may provide an attractive approach to treat mutant p53-expressing tumors.

Optofluidic variable-focus lenses for light manipulation.

This paper presents a planar optofluidic lens for light manipulation utilizing a combination of optofluidic biconvex lens with micromixer. Three light manipulation techniques including tunable optical diverging, collimating and focusing are realized by altering the refractive index of the optofluidic variable-focus lenses formed by solid polydimethylsiloxane (PDMS) walls and tunable liquid lens body. The optical power from the laser input can be increased or decreased with the tuning of the variable-focus lenses' refractive indexes. The optical power adjustment capabilities are demonstrated and characterized. The combinations of benefits of all lens' optical manipulation capabilities, greater mechanical stability, significant increase of optofluidic device's life time and seamless integration with other lab-on-a-chip functionalities provide a promising and versatile optofluidic compartment to integrate with lab-on-a-chip excitation and sensing applications. Optofluidic lens-including system for tunable fluorescence sensing is demonstrated showing 186% increase in detected fluorescence intensity.

Psoriasiform dermatitis in a case of newly diagnosed locally advanced pyriform sinus tumour: Bazex syndrome revisited.

Acrokeratosis paraneoplastica of Bazex is a rare but important paraneoplastic dermatosis, usually manifesting as psoriasiform rashes over the acral sites. It often precedes diagnosis of the associated malignancy, usually that of upper aerodigestive tract squamous cell carcinoma. We present the case of a patient with a newly diagnosed pyriform sinus tumour and associated acrokeratosis paraneoplastica. To the best of our knowledge, this is the first reported case in the local literature.

Flow cytometric assessment of distinct physiological stages within Cryptosporidium parvum sporozoites post-excystation.

Cryptosporidium parvum are protozoan parasites responsible for outbreaks of gastrointestinal disease worldwide. Within the apical complex of this organism reside numerous vesicular secretory organelles and their discharge has been identified as essential for sporozoite motility, cell attachment and penetration. Traditionally, investigation of apical organelle discharge has relied on microscopic and immunochemical hybridization techniques. In this study we demonstrate for the first time how flow cytometry, in combination with vital dye staining, provides an avenue for discrimination of distinct physiological events occurring within Cryptosporidium sporozoites post-excystation. Time-course studies of freshly excysted sporozoites were carried out at 37 degrees C in cell-free medium, stained with the fluorescent dyes SYTO9/PI, DiBAC4(3), Fluo-4 AM or FM1-43 and analysed by flow cytometry. Significant decreases in sporozoite plasma membrane permeability and increased membrane depolarization were found to be accompanied by concomitant increases in intracellular calcium. Subsequent to these changes, large increases in exocytosed vesicular membrane were apparent. In addition, by measuring side and forward angle light scatter we were able to assess changes in internal granularity and size of sporozoites post-excystation. These observations were suggestive of rapid mobilization, utilization and discharge of apical organelles within sporozoites, which we relate to changes in sporozoite infectivity, ATP levels and total secreted soluble protein.

Flexible exportation mechanisms of arthrofactin in Pseudomonas sp. MIS38.

AIMS: To obtain further insights into transportation mechanisms of a most effective biosurfactant, arthrofactin in Pseudomonas sp. MIS38. METHODS AND RESULTS: A cluster genes arfA/B/C encodes an arthrofactin synthetase complex (ArfA/B/C). Downstream of the arfA/B/C lie genes encoding a putative periplasmic protein (ArfD, 362 aa) and a putative ATP-binding cassette transporter (ArfE, 651 aa), namely arfD and arfE, respectively. The arfA/B/C, arfD, and arfE form an operon suggesting their functional connection. Gene knockout mutants ArfD:Km, ArfE:Km, ArfD:Tc/ArfE:Km, and gene overexpression strains MIS38(pME6032_arfD/E) and ArfE:Km(pME6032_arfD/E) were prepared and analysed for arthrofactin production profiles. It was found that the production levels of arthrofactin were temporally reduced in the mutants or increased in the gene overexpression strains, but they eventually became similar level to that of MIS38. Addition of ABC transporter inhibitors, glibenclamide and sodium ortho-vanadate dramatically reduced the production levels of arthrofactin. This excludes a possibility that arthrofactin is exported by diffusion with the aid of its own high surfactant activity. CONCLUSIONS: ArfD/E is not an exclusive but a primary exporter of arthrofactin during early growth stage. Reduction in the arthrofactin productivity of arfD and arfE knockout mutants was eventually rescued by another ABC transporter system. Effects of arfD and arfE overexpression were evident only for 1-day cultivation. Multiple ATP dependent active transporter systems are responsible for the production of arthrofactin. SIGNIFICANCE AND IMPACT OF THE STUDY: Pseudomonas bacteria are characterized to be endued with multiple exporter and efflux systems for secondary metabolites including antibiotics, plant toxins, and biosurfactants. The present work demonstrates exceptionally flexible and highly controlled transportation mechanisms of a most effective lipopeptide biosurfactant, arthrofactin in Pseudomonas sp. MIS38. Because lipopeptide biosurfactants are known to enhance efficacy of bioactive compounds and arfA/B/C/D/E orthologous genes are also found in plant pathogenic P. fluorescens and P. syringae strains, the knowledge would also contribute to develop a technology controlling plant diseases.

A review of the adverse effects of laser hair removal.

Laser hair removal is ever increasing in popularity. Technology is fast advancing, and there are increasingly excessive commercial claims that laser hair removal in all skin types is free of side effects. The aim of this study is to review the evidence from published literature regarding the incidence of adverse effects after laser and light systems for hair removal. A review of the current published literature on the ill effects reported after laser/light-assisted depilation was conducted. Overall incidence of adverse effects after laser/light hair removal appears to be low, with very uncommon permanent sequelae. The two largest studies to date have shown that acute and transient side effects do occur. Higher incidence of pigmentary alterations is associated with the shorter wavelength lasers (up to 19%), particularly with darker skin types, compared with lower incidence using the neodymium-yttrium-aluminium-garnet laser (2-3%). Both studies did not show any long-term side effects or scarring. Laser/light hair removal, carried out by trained professionals, is a safe procedure with a very low incidence of permanent sequelae. The majority of adverse effects are transient and minor. They are more common in darker skin. Longer wavelength devices reduce the risk in darker skin.

The treatment of port-wine stains with the pulsed-dye laser at 2-week and 6-week intervals: a comparative study.

BACKGROUND: The pulsed-dye laser (PDL) is the treatment of choice for port-wine stains (PWS). Multiple treatments are usually necessary, with standard treatment intervals ranging between 6 and 12 weeks. However, there are no studies on the effect of treating PWS at different time intervals, and the ideal time interval between treatments has not yet been agreed. It is uncertain whether treatment is more effective if administered at shorter time intervals. OBJECTIVES: To establish whether the treatment of PWS with the variable pulse width 595-nm (V-beam) PDL at 2-week intervals achieves better results, with no difference in the complication rate, than treatment given at 6-week intervals. METHODS: We prospectively investigated 15 patients with PWS. Each patient had the whole PWS treated at initial visit. Half of the PWS was randomly allocated to be treated at 2 weeks and the other half at 6 weeks from initial visit. Both halves of the PWS thus were treated twice in total, once at the initial visit and the second treatment either at 2 weeks or 6 weeks from initial visit. At 12 weeks an observer blinded to treatment allocation clinically evaluated the results. The outcome measure was lightening of the PWS as measured with a reflectance spectrophotometer. Complications were recorded throughout the study period. RESULTS: Of the 15 patients, 13 completed the study. Three patients had two PWS each treated separately, giving a total of 16 treated PWS sites. In 11 sites (69%), the 2-week interval treatment resulted in greater reduction in reflectance than the 6-week interval treatment. Using the nonparametric Wilcoxon matched-pair signed rank test, the 2-week treatment interval site resulted in greater reduction in reflectance measurements compared with the 6-week treatment interval site (P < 0.01). This agreed closely with independent observer assessment judging that the 2-week treatment interval resulted in better lightening of the PWS than the 6-week treatment interval (P = 0.003). There were no adverse reactions from the treatments. CONCLUSIONS: Preliminary data suggest that a treatment interval of 2 weeks is well tolerated by patients and resulted in greater lightening of the PWS in the majority, compared with a standard 6-week interval. It also has the potential to reduce the total duration of a course of treatment significantly.

Effects of juvenile hormone analogs on new reproductives and colony growth of Pharaoh ant (Hymenoptera: Formicidae).

Two juvenile hormone analogs (JHAs), pyriproxyfen and S-methoprene, were impregnated into dried tuna fish and fed to colonies of Monomorium pharaonis (L.) at very low concentrations (1.0, 2.0, 3.0, 4.0, and 5.0 microg/ml). Its effects on the production of sexuals and colonial growth were observed. Colonies treated with pyriproxyfen yielded sexuals with physical abnormalities. Both female and male sexuals developed bulbous wings, decreased melanization, and died shortly after emergence. Sexuals emerged from colonies treated with S-methoprene did not possess anomalous characteristics. Both pyriproxyfen and S-methoprene did not have significant effects on colonial growth because of the low concentrations of the baits. A commercial bait containing 0.3% S-methoprene (Bioprene-BM) also was evaluated for its efficacy on Pharaoh's ant colonies. Results showed that Pharaoh's ant colonies succumbed to the lethal effects of S-methoprene. Colony members were reduced significantly. Production of queens also decreased significantly in treated colonies and treated queens were unable to lay eggs. JHAs are slow acting and eliminate ant colonies at a relatively slow rate. At low concentrations, pyriproxyfen recorded baffling results, i.e., bulbous wings and demelanized exoskeleton, and it is vital that further studies are initiated to solidify these findings.

Calciphylaxis in a patient with alcoholic liver disease in the absence of renal failure.

Calciphylaxis is a rare, potentially life-threatening syndrome characterized by progressive microvascular and superficial soft tissue calcification, usually seen in patients with chronic renal failure. We describe an unusual case of calciphylaxis in a patient with alcoholic liver disease and normal renal function who responded well to conservative wound care.

Identification and molecular characterisation of the complete genome of a Singapore isolate of hepatitis C virus: sequence comparison with other strains and phylogenetic analysis.

The complete genomic sequence of a Singapore isolate of the hepatitis C virus (HCV) was obtained from serum of an individual chronically infected with HCV. Nine overlapping cDNA clones covering the entire viral genome was amplified by reverse-transcription-polymerase chain reaction (RT-PCR), This isolate (HCV-S1) comprised 9,609 nucleotides (nt), including 341 nt of the complete 5' untranslated region (5' UTR), a single open reading frame of 3,011 amino acids (aa) and 235 nt of the complete 3' UTR. Its genotype was identified as type lb from analyses of its sequences in the 5' UTR, NS3 and NS5B regions. When compared against nine reported HCV isolates, the overall aa homology of HCV-SI was closest with an Australian strain, HCV-A (94%) and a Japanese strain, HCV-JT (93.9%). Phylogenetic analysis revealed that it was most closely related to the Taiwan strain, HCV-TW and another Japanese strain, HCV-K1-R1.