A competitive immunoassay for biotin detection using magnetic beads and gold nanoparticle probes.

Haptens are small molecules with low molecular weight that include biotin and many toxins in food. In this study, we used biotin as a model molecule for hapten detection. In this competitive immunoassay anti-biotin antibody-modified magnetic beads (Ab-MBs) and biotinylated thiol-DNA gold nanoparticles (biotin-GNPs) were used. The assay contains three reactions, the mixing of the sample and Ab-MBs, the capture of biotin-GNPs by Ab-MBs and the magnetic attraction. When biotin molecules were absent, the solution was transparent because biotin-GNPs bound to Ab-MBs which were caught by an external magnetic field. When biotin was present, the supernatant was red because the Ab-MBs bound to the analytes and the gold nanoparticles were still in solution. It was possible to complete all the operating steps in 15 min. The limit of detection (LOD) was 2 pmol. This rapid competitive-immunoassay has potential for application in detection of other haptens.

In vivo toxicologic study of larger silica nanoparticles in mice.

Silica nanoparticles (SiNPs) are being studied and used for medical purposes. As nanotechnology grows rapidly, its biosafety and toxicity have frequently raised concerns. However, diverse results have been reported about the safety of SiNPs; several studies reported that smaller particles might exhibit toxic effects to some cell lines, and larger particles of 100 nm were reported to be genotoxic to the cocultured cells. Here, we investigated the in vivo toxicity of SiNPs of 150 nm in various dosages via intravenous administration in mice. The mice were observed for 14 days before blood examination and histopathological assay. All the mice survived and behaved normally after the administration of nanoparticles. No significant weight change was noted. Blood examinations showed no definite systemic dysfunction of organ systems. Histopathological studies of vital organs confirmed no SiNP-related adverse effects. We concluded that 150 nm SiNPs were biocompatible and safe for in vivo use in mice.

Anthracene photodimerization in a bis-chromophoric hydrogen-bonding receptor.

The photochemistry and photophysics of a bis-anthracenyl hydrogen-bonding receptor (7-(3,5-bis((6-(4-(anthracen-9-yloxy) butanamido)pyridin-2-yl)carbamoyl)phenylhept-6-ynoate, 2) were investigated in a fluid solution. At room temperature, fluorescence and intersystem crossing compete with intramolecular dimerization to form head-to-head and head-to-tail photoproducts, whereas fluorescence is the principal deactivation pathway at low temperature. Time-resolved fluorescence spectroscopy evidences two excimer-like emitting states whose sensitivity to quenching by oxygen is considerably lower than that of intramolecular photodimerization (K(SV) = ca. 450 vs. <100 L mol(-1), respectively). Based on the temperature-dependence and quenching efficiency of photodimerization, a mechanism is proposed in which the ground-state conformation of the tether controls the formation of the HH vs. HT photodimers via a non-emissive intermediate.

Reversible control over molecular recognition in surface-bound photoswitchable hydrogen-bonding receptors: towards read-write-erase molecular printboards.

The synthesis of an anthracene-bearing photoactive barbituric acid receptor and its subsequent grafting onto azide-terminated alkanethiol/Au self-assembled monolayers by using an Cu(I) -catalyzed azide-alkyne reaction is reported. Monolayer characterization using contact-angle measurements, electrochemistry, and spectroscopic ellipsometry indicate that the monolayer conversion is fast and complete. Irradiation of the receptor leads to photodimerization of the anthracenes, which induces the open-to-closed gating of the receptor by blocking access to the binding site. The process is thermally reversible, and polarization-modulated IR reflection-absorption spectroscopy indicates that photochemical closure and thermal opening of the surface-bound receptors occur in 70 and 100 % conversion, respectively. Affinity of the open and closed surface-bound receptor was characterized by using force spectroscopy with a barbituric-acid-modified atomic force microscope tip.

A combined therapy using stimulating auricular acupoints enhances lower-level atropine eyedrops when used for myopia control in school-aged children evaluated by a pilot randomized controlled clinical trial.

OBJECTIVE: This study was designed to compare the reduction in myopia progression in patients treated with atropine eyedrops alone with patients treated with a combined treatment of atropine and stimulation of the auricular acupoints. METHODS: This study was a randomized single-blind clinical controlled trial. A total of 71 school-aged children with myopia, who fulfilled the eligibility criteria, were recruited. They were randomly assigned into three groups. These were 22 treated with the 0.25% atropine (0.25A) only, 23 treated with the 0.5% atropine (0.5A) only and 26 treated with 0.25% atropine together with stimulation of the auricular acupoints (0.25A+E). The differences in the post-treatment effects among these three groups were statistically assessed. The primary outcome parameter was myopia progression, which was defined as diopter change per year (D/Y) after cycloplegic refraction measurement. RESULTS: The mean myopia progression of the 0.25A group was 0.38+/-0.32 D/Y. No significant difference in mean myopia progression was found between the 0.5A (0.15+/-0.15 D/Y) and 0.25A+E (0.21+/-0.23 D/Y) groups. However, there was a markedly reduced myopia progression in the 0.25A+E group compared to the 0.25A group (p<0.05). Furthermore, there was no statistical difference among these three groups in axial length elongation (ALE) of eye during this stage of the investigation. CONCLUSIONS: This study demonstrates that there was efficacy in stimulating the auricular acupoints and this enhanced the action of 0.25% atropine as a means of myopia control. The result was an effect almost equal to that of 0.5% atropine alone. There is also a need that the ALE of the eye should be further investigated over a longer period using the combined therapy.

Preseptal and orbital cellulitis: a 10-year review of hospitalized patients.

BACKGROUND: Preseptal and orbital cellulitis range in severity from minor to potentially severe complications. The purpose of this study is to describe the clinical features of patients with preseptal or orbital cellulitis in one medical center in Taiwan, and to assess the effectiveness of treatments and the complications. METHODS: Patients admitted between 1996 and 2005 to Taipei Veterans General Hospital under the diagnosis of preseptal or orbital cellulitis were retrospectively reviewed. The demographics, administrative history, past history, clinical presentations, treatments, and complications were analyzed. RESULTS: In total, 94 patients fulfilling the diagnostic criteria for preseptal or orbital cellulitis were identified (67 had preseptal cellulitis, 27 had orbital cellulitis). While paranasal sinus disease was the most common predisposing cause in orbital cases, skin lesions in children and dacryocystitis in adults were the most common in preseptal cases. Microbiologic investigations showed variable results, but the most common pathogen isolated was Staphylococcus aureus. Cultures from eye swabs and local abscesses gave the highest positive yield. Blood cultures were taken in some patients, but the positive rate was extremely low. Treatments included intravenous antibiotics alone, or intravenous antibiotics combined with surgical drainage. Only one case had permanent ocular motility impairment after removal of the orbital foreign body. CONCLUSION: Despite the past history of potential morbidity and even mortality from orbital cellulitis, early diagnosis and prompt treatment with proper antibiotics and/or surgical intervention can achieve a good prognosis.

Relapsing Mooren's ulcer after amniotic membrane transplantation combined with conjunctival autografting.

PURPOSE: To report a patient with Mooren's ulcer that relapsed 2 months after amniotic membrane (AM) transplantation and conjunctival autografting and its subsequent retreatment. DESIGN: Interventional case report. METHODS: We performed multilayered AM transplantation and conjunctival autografting from the opposite healthy eye to treat a corneoscleral perforation caused by Mooren's ulcer in a 60-year-old woman. MAIN OUTCOME MEASURES: Reformation of the anterior chamber, absence of inflammation, and restoration of visual acuity. RESULTS: The perforated corneoscleral lesion was sealed successfully by the AM and conjunctiva graft and led to a stable condition for 2 months. Relapsing corneal edema, keratic precipitates, and cell infiltration occurred along the margin of the conjunctival graft with severe vessel engorgement. After removing the conjunctival graft and regrafting of additional AM, the lesion subsided for at least 1 year. CONCLUSIONS: Amniotic membrane transplants may be useful in treating corneal perforation of immunologic origin, but conjunctiva and its vessels may play a role in the process of peripheral corneal destruction of Mooren's ulcer.