Tin oxide nanoparticle formation using a surface modifying agent

This work presents results concerning the preparation of redispersible tin oxide nanoparticles achieved by using Tiron molecule ((OH)(2)C(6)H(2) (SO(3)Na)(2)) as surface modifying agent. The adsorption isotherm measurements show that an amount of 10 wt.% of Tiron is need to recover the SnO(2) nanoparticles surface with a monolayer. These nanoparticles can be easily redispersed in tetramethyl ammonium hydroxide at pH greater than or equal to11 until a powder concentration of 12 vol.% of tin. Under these conditions, hydrodynamic particle size is about 7 nm and increases until 52 nm at pH 6 due to the aggregation phenomenon. The time evolution of the viscoelastic properties indicates that the suspensions at pH 12.5, containing 12 vol.% tin oxide and 10 wt.% of surface modifier are kinetically stable. After thermal treatment at different temperature the powder characterisation evidences that the presence of Tiron monolayer at the nanoparticles surface increases the thermal stability of the porous texture and prevent the micropore size growth. This set of results contributes to satisfy the demand for more controlled synthesis of nanoparticles with high thermal stability as required for fabrication of ultrafiltration ceramic membranes. (C) 2004 Elsevier Ltd. All rights reserved.

Origin of nuclear and chromosomal alterations derived from the action of an aneugenic agent-Trifluralin herbicide

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

EPR of Mn as densifying agent in SnO2 powders

Electron Paramagnetic Resonance (EPR) spectra have been obtained at room temperature and at X-band in powders of SnO2 doped with Mn from 0.3 to 10% and submitted to heat treatment from 500 to 900 °C. Mn ions are probably located at particle surfaces as Mn2+, evidenced by its single EPR line which narrows by the exchange interaction effect due to particle growth observed by the BET technique. In samples doped above 1% formation Of Mn3O4 is detected on particle surfaces and a small quantity of Mn is thermally diffused into the bulk as Mn4+. Powders compacted and sintered at 1300 °C confirmed that Mn2+ ions remain at grain boundaries acting as densifying agent.

A comparative evaluation of open loop and closed loop drug administration strategies in the treatment of AIDS.

In recent years, many researchers in the field of biomedical sciences have made successful use of mathematical models to study, in a quantitative way, a multitude of phenomena such as those found in disease dynamics, control of physiological systems, optimization of drug therapy, economics of the preventive medicine and many other applications. The availability of good dynamic models have been providing means for simulation and design of novel control strategies in the context of biological events. This work concerns a particular model related to HIV infection dynamics which is used to allow a comparative evaluation of schemes for treatment of AIDS patients. The mathematical model adopted in this work was proposed by Nowak & Bangham, 1996 and describes the dynamics of viral concentration in terms of interaction with CD4 cells and the cytotoxic T lymphocytes, which are responsible for the defense of the organism. Two conceptually distinct techniques for drug therapy are analyzed: Open Loop Treatment, where a priori fixed dosage is prescribed and Closed Loop Treatment, where the doses are adjusted according to results obtained by laboratory analysis. Simulation results show that the Closed Loop Scheme can achieve improved quality of the treatment in terms of reduction in the viral load and quantity of administered drugs, but with the inconvenience related to the necessity of frequent and periodic laboratory analysis.

Subgingival utilization of a 1% chlorhexidine collagen gel for the treatment of periodontal pockets. A clinical and microbiological study.

This study evaluates the effect of subgingival irrigation with a 1% chlorhexidine collagen gel in periodontal pockets as an adjunct procedure to scaling and root planing (SRP). Thirty-seven sites with probing depth (PD) of 5-7 mm and BANA positive in 6 patients with chronic periodontal disease were selected. Sites were assigned to different treatment groups consisting of SRP only (group 1), SRP + irrigation with collagen gel (group 2), or SRP + irrigation with collagen gel containing 1% chlorhexidine (group 3). Subgingival irrigation was performed after initial SRP and at 7, 14 and 21 days. Clinical measurements including PD, plaque index (PI), gingival index (GI), gingival recession (GI), bleeding on probing (BOP) and clinical attachment level (CAL) were performed at the selected sites at baseline, 60 and 90 days and the BANA test was performed on plaque samples from the same sites at baseline and 90 days. There was an improvement in clinical parameters in all groups with a significantly greater decrease in GI and bleeding in the chlorhexidine group. There was a greater reduction of BANA positive sites in groups 2 and 3. The authors concluded that 1% chlorhexidine collagen gel is a promising adjunct to SRP in the treatment of adult periodontitis.

Lethal photosensitization in microbiological treatment of ligature-induced peri-implantitis: a preliminary study in dogs

This pilot study evaluated, by culture testing, the effectiveness of lethal photosensitization for the microbiological treatment of peri-implantitis in dogs. Experimental peri-implantitis was induced by ligature placement for 2 months. Following ligature removal, plaque control was instituted by scrubbing with 0.12% chlorhexidine daily for 12 months. Subsequently, mucoperiosteal flaps were elevated for scaling the implant surface. Microbial samples were obtained with paper points before and after treatment of implant surfaces by means of 100 microg/ml toluidine blue O (TBO,) and were exposed, for 80 s, to light with a wavelength of 685 nm from a 50 mW GaAlAs diode laser. The mean initial and final bacterial counts were 7.22 +/- 0.20 and 6.84 +/- 0.44 CFU/ml, respectively for TVC (P < 0.0001); 6.19 +/- 0.45 and 3.14 +/- 3.29 CFU/ml for P. intermedia/nigrescens (P = 0.001); 5.98 +/- 0.38 and 1.69 +/- 2.90 CFU/ml for Fusobacterium spp. (P = 0.001); and 6.07 +/- 0.22 to 1.69 +/- 2.94 CFU/ml for beta-hemolytic Streptococcus (P = 0.0039). It may be concluded that lethal photosensitization resulted in a reduction of the bacterial count. Complete elimination of bacteria was achieved in some samples.

Conservative treatment of a radicular cyst in a 5-year-old child: A case report

The present report describes the management of a radicular cyst in a 5-year-old child. The treatment comprised extraction of the primary teeth involved followed by marsupialization. A removable appliance with a resin extension penetrating into the cystic cavity was used to help decompress the lesion. This treatment allowed rapid healing of the lesion and eruption of the permanent incisors without the need for orthodontic treatment.

Systemic use of metronidazole in the treatment of chronic periodontitis: a pilot study using clinical, microbiological, and enzymatic evaluation

The aim of the present parallel, double-blind investigation was to evaluate the effect of using systemic metronidazole alone or associated to scaling and root planing on adult chronic periodontal disease, monitored at baseline, 30, 60 and 90 days. Twelve subjects were divided into three groups: the first group (Group I - 22 sites) was submitted to scaling and root planing (SRP) alone; the second group (Group II - 30 sites) received SRP and 250 mg of metronidazole (3 times a day for 10 days), and the third group (Group III - 31 sites) was treated with metronidazole alone. The clinical parameters evaluated were probing depth (PD), clinical attachment level (CAL), plaque index (PlI), gingival index (GI) and bleeding upon probing (BP). Microbiological (BANA test) and enzymatic (Pocket Watch) tests were also performed. All three proposed treatments produced significant improvements in clinical conditions of subjects, from baseline, 30, 60 and 90-day period, except for clinical attachment level. The results obtained by microbiological and enzymatic tests did not show statistical differences among the groups for the 90-day period (r = 0.7924 and r = 0.7757, respectively). In relation to clinical parameters, statistical differences among groups were observed only for the gingival index (p = 0.0261) between Groups I and II, and probing depth (p = 0.0124) between Group I and the others. We conclude that the use of systemic metronidazole did not produce additional effects on the microbiological conditions of these patients with chronic periodontal disease.

Argon laser for treatment of benign eyelid tumors

Small lesions located in the skin might be treated using the laser system. The purpose of this is to report the therapy of benign eyelid tumors using argon laser. Forty-four benign eyelid tumors were treated using argon blue-green laser with spot size of 500 μm, power from 1000 to 1200 mW and 0.3 second exposure time. The eyelid tumors were located mainly in the upper eyelid (65.9%) and the skin tag was the most frequent treated lesion (43.2%). The average number of laser shots to treat the lesions was 165. There was not observed any complication and all patients were satisfied with the results. The authors are considering the argon laser a benefit therapeutic method to treat benign tumors located in the eyelids.

Treatment of developmental defect of upper lip with carbon dioxide laser radiation (CO2): First surgical time

With the exception of the cleft lip, developmental defects (DD) of the lip are rare. The upper lip originates from the ectomesenchyme and is formed by the merging of the nasal medial and lateral processes with the maxillary process. Disturbances during this formation period can cause DD with functional and/or esthetic repercussions. We present a case of DD of the upper lip in a patient with a history of progressive growth of the left lateral portion of the upper lip that occurred from the time of birth until the age of 22 years. Clinical examination revealed hypertrophy of the area from the left philtral columns to the left commissure of the lip, extending the portion of the surface mucosa creating a flaccid and asymptomatic tissue mass. All other buccal structures appeared to be within normal limits and without any evidence of defects or deformities. In the surgical planning we decided to carry out corrective surgery in two phases. The first phase accomplished a conservative excision of the total abnormal labial tissue mass with a CO2 laser radiation (5 W in continuous mode, bunch diameter φ = 0.6 mm with a power density of 768 W/cm2 and fluency of 0.231 J/cm2) being careful to preserve the vermilion portion of the lip. Postsurgical clinical evaluations were done every three days until the skin sutures were removed and then every seven days until two months post surgery. While the entire mass of excessive tissue could not be completely removed, the removal of the excessive mucosal tissue produced a very good outcome relative to lip function, with a good esthetic result without scarring, and good tissue mobility. The results showed that the CO2 laser is an extremely useful instrument that can provide excellent control of the surgical field and allow for healing that produces excellent functional and esthetic results. © 2005 Taylor & Francis.

Bezafibrate for the treatment of hypertriglyceridemia in HIV1-infected patients on highly active antiretroviral therapy

The use of highly active antiretroviral therapy (HAART) in HIV-infected patients has been associated with the development of risk factors for cardiovascular diseases (CD) including dyslipidemia and insulin resistance, hypertriglyceridemia being the most frequent metabolic disturbance in these patients. Fibrates are indicated when hypertriglyceridemia is accentuated and persists for over six months. We evaluated the efficacy and safety of bezafibrate for the treatment of hypertriglyceridemia in HIV-infected individuals on HAART. All patients received 400mg/day of bezafibrate and were evaluated three times: Mo (pre-treatment), M1 (one month after treatment), and M2 (six months after treatment). Fifteen adult individuals, eight males and seven females with mean age = 41.2 ± 7.97 years and triglyceride serum levels ≥400mg/dL were included in the study. Smoking, alcohol ingestion and sedentarism rates were 50%, 6.66% and 60%, respectively. Family history of CD, hypertension and diabetes mellitus was reported in 33.3%, 40% and 46.7% of the cases, respectively, while dyslipidemia was reported by only 13.3%. More than half of the patients were using a protease inhibitor plus a nucleotide analog transcriptase inhibitor. Eutrophy and tendency toward overweight were observed at all three study time points. There were significant reductions in triglyceride serum levels from Mo to M1 and from Mo to M2. No significant changes were observed in the serum levels of creatine phosphokinase, hepatic enzymes, CD4 +, CD8 + and viral load. Therefore, bezafibrate seems to be safe and effective for the reduction of hypertriglyceridemia in HIV-infected patients on HAART. © 2006 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.

Clinical evaluation of an ointment with 10% metronidazole and 2% lidocaine in the treatment of alveolitis.

AIM: In this study, the authors evaluate the use of a 10% metronidazole and 2% lidocaine ointment, using a lanolin base and mint as flavoring, to treat alveolitis in humans. METHODS: Twenty-five patients, with a diagnosis of alveolitis, were treated in the following way: locoregional anesthesia; surgical cleaning of the socket with alveolar curettes; saline solution irrigation with a 20 ml disposable syringe; and complete filling of the socket with the ointment. RESULTS: The analysis of the results showed that the painful symptoms were severe before and on the day of the treatment in 17 (68%) of the 25 patients treated. Post-treatment analysis presented 2 patients (18%) with severe painful symptoms after 24 h of the treatment and complete remission of painful symptoms after 48 h of the treatment with the ointment. CONCLUSIONS: Based on the results, it is possible to conclude that the 10% metronidazole and 2% lidocaine ointment, with mint flavoring and lanolin as a base, can be used to treat alveolitis.

Information for the diagnosis and treatment of root resorption due to tooth replantation.

A favorable prognosis after tooth avulsion depends on some variables, such as the extra-alveolar period and storage medium. Vitality of the periodontal ligament cells is considered a critical factor for a successful outcome without root resorption. The dental surgeon is provided with clinical information and radiographic findings to establish a diagnosis and may rely on current available guidelines. Once trauma has occurred, treatment must be quick and effective, and periodic follow-up must be performed. Clinical, radiographic, and histologic characteristics for each type of root resorption due to tooth replantation are presented, with the aim to provide information for the diagnosis and treatment of healing complications.

Treatment of pulmonary thromboembolism in patients with systemic blood pressure stability and right ventricular dysfunction

Pulmonary thromboembolism (PTE) ranges from incidental, clinically unimportant thromboembolism to massive embolism with sudden death. Its treatment is well established in two groups of patients: heparin for those with normal systemic blood pressure without right ventricular dysfunction (RVD) and thrombolysis for those with RVD and circulatory shock. In an intermediate group of patients with systemic blood pressure stability combined with RVD, which is usually associated with worse outcome, the treatment is controversial. There are authors who strongly suggest thrombolysis while others contraindicate this procedure and recommend anticoagulation with heparin. This is a narrative review that includes clinical trials comparing thrombolysis and heparin for the treatment of PTE patients with systemic blood pressure stability and RVD published since 1973. The results show that there are only four trials on this subject with less than 500 patients. Many PTE patients with systemic blood pressure stability and RVD might benefit from thrombolysis but, on the other hand, the risk for hemorrhagic events may be increased. Large randomized clinical trials are required to clarify this. © 2008 Bentham Science Publishers Ltd.