Fate of GdF3 nanoparticles-loaded PEGylated carbon capsules inside mice model: a step toward clinical application.

The successful translation of nanostructure-based bioimaging and/or drug delivery system needs extensive in vitro and in vivo studies on biocompatibility, biodistribution, clearance, and toxicity for its diagnostic applications. Herein, we have investigated the in vitro cyto-hemocompatibility, in vivo biodistribution, clearance, and toxicity in mice after systemic administration of GdF3 nanoparticles loaded PEGylated mesoporous carbon capsule (GdF3-PMCC)-based theranostic system. In vitro cyto-hemocompatibility study showed a very good biocompatibility up to concentration of 500 µg/ml. Biodistribution studies carried out from 1 h to 8 days showed that GdF3-PMCC was found in major organs, such as liver, kidney, spleen, and muscle till 4th day and it was negligible in any tissue after 8th day. The clearance study was carried out for a period of 8 days and it was observed that the urinary system is the main route of excretion of GdF3-PMCC. The tissue toxicity study was done for 15 days and histopathological analysis indicated that the GdF3-PMCC based theranostic system does not have any adverse effect in tissues. Thus, PMCCs are nontoxic and can be applied as theranostic agents in contrast to the other carbon-based systems (PEGylated carbon nanotubes and PEGylated graphene oxide) which showed significant toxicity.

Effect of fluoride slow-release glass devices on salivary and gingival crevicular fluid levels of fluoride: A pilot study.

Objectives: To estimate the effect of fluoride slow-release glass devices on the levels of fluoride in a pooled sample of human gingival crevicular fluid and in human saliva. Materials and Methods: Ten healthy adult volunteers wore fluoride slow-release glass devices for 3 months in a longitudinal experimental clinical pilot study. Whole unstimulated human saliva and gingival crevicular fluid were collected using paper points at baseline, after 2 weeks and at 3 months and analysed for their fluoride levels using ion chromatography and fluoride electrode. Results: No adverse effects were reported, and the Löe Plaque and Gingival Index remained low (0.22). The saliva determination of fluoride using the fluoride electrode showed an increase after 3 months from 0.02 ± 0.04 ppm to 0.06 ± 0.12 ppm, whereas the ion chromatography showed an increase from 0.15 ± 0.10 ppm to 0.44 ± 0.36 ppm. The fluoride levels in a pooled sample of gingival crevicular fluid from four intraoral sites were determined using the ion chromatography, and the results showed that after 3 months, the fluoride levels were still low (0.71 ± 0.34 ppb) similar to those at baseline (0.74 ± 0.31 ppb). Conclusions: The fluoride concentration in a pooled sample of gingival crevicular fluid was reported to be low with a range from 0.46 to 0.75 ppb and was not changed by placement of fluoride slow-release glass devices. The fluoride concentration in unstimulated human saliva showed an increase after 3 months when the fluoride slow-release glass devices were attached when determined with both the fluoride electrode (from .02 ± 0.04 ppm to 0.06 ± 0.12 ppm) and ion chromatography (from 0.15 ± 0.10 ppm to 0.44 ± 0.36 ppm).

Pro-neurogenic, Memory-Enhancing and Anti-stress Effects of DF302, a Novel Fluorine Gamma-Carboline Derivative with Multi-target Mechanism of Action.

A comparative study performed in mice investigating the action of DF302, a novel fluoride-containing gamma-carboline derivative, in comparison to the structurally similar neuroprotective drug dimebon. Drug effects on learning and memory, emotionality, hippocampal neurogenesis and mitochondrial functions, as well as AMPA-mediated currents and the 5-HT6 receptor are reported. In the step-down avoidance and fear-conditioning paradigms, bolus administration of drugs at doses of 10 or 40 mg/kg showed that only the higher dose of DF302 improved long-term memory while dimebon was ineffective at either dosage. Short-term memory and fear extinction remained unaltered across treatment groups. During the 5-day predation stress paradigm, oral drug treatment over a period of 2 weeks at the higher dosage regimen decreased anxiety-like behaviour. Both compounds supressed inter-male aggression in CD1 mice, the most eminent being the effects of DF302 in its highest dose. DF302 at the higher dose decreased floating behaviour in a 2-day swim test and after 21-day ultrasound stress. The density of Ki67-positive cells, a marker of adult neurogenesis, was reduced in the dentate gyrus of stressed dimebon-treated and non-treated mice, but not in DF302-treated mice. Non-stressed mice that received DF302 had a higher density of Ki67-positive cells than controls unlike dimebon-treated mice. Similar to dimebon, DF302 effectively potentiated AMPA receptor-mediated currents, bound to the 5-HT6 receptor, inhibited mitochondrial permeability transition and displayed cytoprotective properties in cellular models of neurodegeneration. Thus, DF302 exerts multi-target effects on the key mechanisms of neurodegenerative pathologies and can be considered as an optimized novel analogue of the neuroprotective agent dimebon.

Porphyrin shell microbubbles with intrinsic ultrasound and photoacoustic properties.

Porphyrin-phospholipid conjugates were used to create photonic microbubbles (MBs) having a porphyrin shell ("porshe"), and their acoustic and photoacoustic properties were investigated. The inclusion of porphyrin-lipid in the MB shell increased the yield, improved the serum stability, and generated a narrow volumetric size distribution with a peak size of 2.7 ± 0.2 µm. Using an acoustic model, we calculated the porshe stiffness to be 3-5 times greater than that of commercial lipid MBs. Porshe MBs were found to be intrinsically suitable for both ultrasound and photoacoustic imaging with a resonance frequency of 9-10 MHz. The distinctive properties of porshe MBs make them potentially advantageous for a broad range of biomedical imaging and therapeutic applications.

[The experimental search of immunological criteria for identifying stages of development of chronic fluoride intoxication].

The experiment has shown the staging of the development of immune response to the chronic fluoride intoxication. Diagnostic criteria of the initial compensation stage are: leukocytosis against the background of reduced number of lymphocytes and increased one of monocytes; high levels of ceruloplasmin in blood plasma, a progressive increase in TNFalpha and cytokine IL-10. At the decompensation stage there are: leukocytosis with increased number of neutrophils; low levels of ceruloplasmin and the cytokines IL-1beta, IL-4 and the high level of TNFalpha, IL-6, IL-10. At the stage of exhaustion there are: leukopenia against the background of lymphocytosis, a high level of Hp, the low values of the level of IgM, IgG.

[Significance of urinary uracil measurement following administration of DPD inhibitory fluoropyrimidine(DIF)products].

Individual differences in 5-FU metabolism are mainly attributed to individual differences in the activity of DPD, an enzyme that can metabolize more than 85% of 5-FU. Because urinary uracil is a reflection of DPD activity, it is measured to predict and prevent the occurrence of side effects caused by pyrimidine-type chemotherapeutic agents. From urinary uracil values measured in 84 gastrointestinal cancer patients, 0-60 mmol/g.creatinine was set as a standard. In patients whose urinary uracil values exceeded the standard, 5-FU tended to be accumulated when S-1, a DIF product, was administered and side effects, such as anorexia, vomiting and diarrhea occurred immediately after the start of S-1 administration. If an appropriate DIF product is selected and its dosage set based on the patient's urinary uracil value, the occurrence of side effects would be reduced. Subsequently, a continuation of medication would be possible.

Analysis of hydrofluoric acid penetration and decontamination of the eye by means of time-resolved optical coherence tomography.

So far the study of chemical burns has lacked techniques to define penetration kinetics and the effects of decontamination within biological structures. In this study, we aim to demonstrate that high-resolution optical coherence tomography (HR-OCT) can close this gap. Rabbit corneas were exposed ex vivo to 2.5% hydrofluoric acid (HF) solution, and microstructural changes were monitored in the time domain by OCT imaging. HF application and penetration resulted in shrinkage of the corneal thickness, interpreted as a result of osmolar changes and of loss of water-binding capacity, and a substantial increase in OCT signal amplitudes. The effectiveness of different rinsing solutions on the chemical burn was also evaluated. With tap water and with 1% calcium gluconate, the deep corneal stroma remained clear until the end of the rinsing period but became opaque afterwards. With Hexafluorine, the cornea remained clear for 60 min after rinsing ceased. We conclude that HR-OCT can assist in the clinical evaluation of an ex vivo eye irritation test, and that decontamination of an HF burn using Hexafluorine is efficient.

Hexafluorine vs. standard decontamination to reduce systemic toxicity after dermal exposure to hydrofluoric acid.

INTRODUCTION: Dermal exposure to hydrofluoric acid (HF) may cause severe burns and systemic toxicity. Hexafluorine (Prevor, France) is a product marketed as an emergency decontamination fluid for HF skin and eye exposures. Documentation concerning Hexafluorine is scanty, and a recent study indicates that its ability to reduce HF burns is at most equal to that of water. OBJECTIVE: The present study was conducted to evaluate Hexafluorine's capacity to reduce HF-induced systemic toxicity. METHODS: Sprague Dawley rats were anesthetized, catheterized in the left femoral artery, and shaved on their back. A filter paper (3.5 x 6 cm) was soaked in 50% HF and applied on the back of each rat for 3 min. Thirty seconds after removal of the paper, a 3-min rinsing with either 500 mL Hexafluorine (group H), 500 mL water (group W), or 500 mL water followed by a single application of 2.5% calcium gluconate gel (group Ca) was carried out. Blood samples were analyzed for ionized calcium and potassium (before injury and 1, 2, 3, and 4 h after) and also for ionized fluoride (1, 2, and 4 h after injury). RESULTS: The animals developed hypocalcemia, hyperkalemia, and hyperfluoridemia after the HF exposure. The only significant difference observed among the groups was in serum potassium at 1 h between group Ca and group W. However, there was a constant trend toward milder hypocalcemia and less pronounced hyperkalemia in group Ca compared to the other groups. There were no differences in the electrolyte disturbances between the Hexafluorine-treated animals and those treated with water only. Five of 39 animals died before completion of the experiment as a result of the HF exposure, one from group Ca and two from each of the other two groups. CONCLUSION: In this experimental study, decontamination with Hexafluorine was not more effective than water rinsing in reducing electrolyte disturbances caused by dermal exposure to hydrofluoric acid.

Selection of 2'-fluoro-modified RNA aptamers for alleviation of cocaine and MK-801 inhibition of the nicotinic acetylcholine receptor.

The nicotinic acetylcholine receptor (nAChR) belongs to a group of five structurally related proteins that regulate signal transmission between approximately 10(12) cells of the mammalian nervous system. Many therapeutic agents and abused drugs inhibit the nAChR, including the anti-convulsant MK-801 and the abused drug cocaine. Many attempts have been made to find compounds that prevent inhibition by cocaine. Use of transient kinetic techniques to investigate the inhibition of the receptor by MK-801 and cocaine led to an inhibition mechanism not previously proposed. The mechanism led to the development of combinatorially synthesized RNA ligands that alleviate inhibition of the receptor. However, these ligands are relatively unstable. Here we determined whether much more stable 2'-fluoro-modified RNA ligands can be prepared and used to study the alleviation of receptor inhibition. Two classes of 2'-fluoro-modified RNA ligands were obtained: One class binds with higher affinity to the cocaine-binding site on the closed-channel form and, as predicted by the mechanism, inhibits the receptor. The second class binds with equal or higher affinity to the cocaine-binding site on the open-channel form and, as predicted by the mechanism, does not inhibit the receptor, and does alleviate cocaine and MK-801 inhibition of the nAChR. The stability of these 2'-fluoro-RNAs expands the utility of these ligands.

Composição percentual e quantificação de flúor incorporado ao cemento e dentina em raízes de molares permanentes recém extraídos e submetidos ao polimento convencional e aplicações tópicas de produtos comerciais fluoretados

Para o desenvolvimento do trabalho, foram utilizados 3 (três) produtos comerciais, contendo flúor na composição: fosfoflúor (solução), Fluorident (gel) e pasta profilática (inodon). Esses compostos fluoretados foram aplicados topicamente em 30 raízes de molares permanentes inferiores. As variações quantitativas entre os diferentes grupos estudados, apresentam maior incorporação de flúor (cemento-dentina), para o grupo tratado com o composto Fluorident em relação aos demais grupos

Resultado del estudio de aplicación de laca de flúor. Experiencia después de 4 y medio años / Result of the study on application of fluorine shellac. Experiences after four and a half years

Se seleccionaron 350 niños de uno y otro sexos, cuyas edades oscilaban entre los 6 y los 12 años, para realizarles investigaciones a largo plazo. En ellas se registró disminución de la prevalencia de las caries del 39 porciento. Se recomienda la utilización de laca de flúor como una medida efectiva y de fácil aplicación desde el punto de vista organizativo, para la prevención colectiva de las caries dentales(AU)