Development and Evaluation of Buccal Films Based on Chitosan for the Potential Treatment of Oral Candidiasis.

In this work, chitosan films were prepared by a casting/solvent evaporation methodology using pectin or hydroxypropylmethyl cellulose to form polymeric matrices. Miconazole nitrate, as a model drug, was loaded into such formulations. These polymeric films were characterized in terms of mechanical properties, adhesiveness, and swelling as well as drug release. Besides, the morphology of raw materials and films was investigated by scanning electron microscopy; interactions between polymers were analyzed by infrared spectroscopy and drug crystallinity studied by differential scanning calorimetry and X-ray diffraction. In addition, antifungal activity against cultures of the five most important fungal opportunistic pathogens belonging to Candida genus was investigated. Chitosan:hydroxypropylmethyl cellulose films were found to be the most appropriate formulations in terms of folding endurance, mechanical properties, and adhesiveness. Also, an improvement in the dissolution rate of miconazole nitrate from the films up to 90% compared to the non-loaded drug was observed. The in vitro antifungal activity showed a significant activity of the model drug when it is loaded into chitosan films. These findings suggest that chitosan-based films are a promising approach to deliver miconazole nitrate for the treatment of candidiasis.

Prospective Epstein-Barr virus-related post-transplant lymphoproliferative disorder prevention program in pediatric allogeneic hematopoietic stem cell transplant: virological monitoring and first-line treatment.

BACKGROUND: In 28 pediatric allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients, we aimed to evaluate: (i) the impact of routine Epstein-Barr virus (EBV) DNA monitoring on the development of EBV-related post-transplant lymphoproliferative disorder (EBV-PTLD); (ii) the incidence of EBV infection and the potential risk factors; and (iii) the suitability of whole blood (WB) as clinical specimen to monitor the risk of patients to develop EBV-PTLD. METHODS: Quantitative real-time polymerase chain reaction assay was performed on WB samples for all patients. EBV DNA quantification also in peripheral blood mononuclear cells (PBMCs) samples was adopted for the patients at higher risk of developing EBV-PTLD (≥ 10,000 copies/mL WB). RESULTS: High EBV DNAemia levels were observed in 37.5% of the actively infected recipients (57.1%). Severe aplastic anemia, matched-unrelated donor transplant, the reduced-intensity conditioning regimen and, to a lesser extent, the in vivo T-cell depletion with anti-thymocyte immunoglobulin were associated with high viral load. A significant correlation between EBV DNA levels in WB and PBMC samples was obtained (r = 0.755, P < 0.001). A similar kinetics of EBV DNA in the 2 blood compartments was observed. Clinically, both specimen types appeared to be equally informative to assess the risk of patients to develop PTLD. On the basis of EBV DNAemia levels, in 3 patients (10.7%) immunosuppressive therapy was reduced and 1 patient (3.5%) received early treatment for probable EBV disease. No patients developed EBV-PTLD. CONCLUSION: WB proved to be a suitable clinical specimen to monitor EBV DNA load after allo-HSCT for the management of EBV infection and PTLD prevention.

Formulation and in-vitro efficacy of antifungal mucoadhesive polymeric matrices for the delivery of miconazole nitrate.

Oral candidiasis is the most common opportunistic infection affecting patients with the human immunodeficiency virus. Miconazole buccal tablets or miconazole gel are approved for the treatment of oropharyngeal candidiasis. However, buccal films present more flexibility and also offer protection for the wounded mucosa, reducing pain. Due to their small size and thickness, buccal films may improve patients' compliance, compared to tablets. Additionally, they may increase the relatively short residence time on the mucosa of oral gels, which are easily removed by saliva. Polymeric films loaded with miconazole nitrate were prepared by a casting/solvent evaporation methodology using chitosan, carbopol, gelatin, gum arabic, and alginate to form the polymeric matrices. The morphology of films was investigated by scanning electron microscopy; interactions between polymers were analyzed by infrared spectroscopy and drug crystallinity by differential thermal analysis and X-ray diffraction. Films were characterized in terms of thickness, folding endurance, tensile properties, swelling, adhesiveness, and drug release. Finally, the antifungal activity against cultures of the five most important fungal opportunistic pathogens belonging to Candida genus was investigated. The more appropriate formulations were those based on chitosan-gelatin and chitosan-carbopol which showed good mechanical properties and adhesiveness, a relative low swelling index, improved drug release, and showed better in vitro activity against Candida cultures than miconazole nitrate raw material. Thus, it will be possible to produce a new pharmaceutical form based on polymeric films containing chitosan and miconazole nitrate, which could be loaded with low drug concentration producing the same therapeutic effect against Candida cultures.

Congenital cytomegalovirus infection: patterns of fetal brain damage.

Cytomegalovirus (CMV) is the most prevalent infectious agent causing neurological dysfunction in the developing brain. This study analysed the different patterns of tissue damage, particularly in the brain, of fetuses with documented CMV infection. We studied 45 fetuses at 20-21 weeks of gestation with congenital CMV infection documented by invasive positive prenatal diagnosis. At the time of amniocentesis, abnormal ultrasound findings had been recorded for 13 of the 45 fetuses (29%). Histological and immunohistochemical characterization was performed on the placenta, brain, heart, lung, liver, kidney, and pancreas. The different degrees of brain damage were correlated with tissue viral load, inflammatory response, placental functionality, and extramedullary haematopoiesis. Even though a high CMV load was detected in all amniotic fluids, brain infection occurred in only 62% of the fetuses and with different degrees of severity. Tissues with a low viral load showed a globally weak inflammatory response, and fetuses had only mild brain damage, whereas tissues with a high CMV load showed prominent infiltration of the activated cytotoxic CD8(+) T-lymphocytes responsible for immune-mediated damage. Furthermore, severe placental infection was associated with diffuse villitis and necrosis, consistent with functional impairment and possible consequent hypoxic cerebral damage. Brain injury induced by CMV congenital infection may be the result of uncontrolled viral replication, immune-mediated damage by cytotoxic CD8(+) T-lymphocytes, and, in the presence of placental insufficiency, fetal hypoxia.

Monitoring cytomegalovirus T-cell immunity in small bowel/multivisceral transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) is a major cause of graft failure and posttransplantation mortality in intestinal/multivisceral transplantation. CMV infection exhibits a wide range of clinical manifestations from asymptomatic infection to severe CMV disease. STUDY'S PURPOSE: The purposes of this study were to assess the utility of measuring CMV-specific cellular immunity in bowel/multivisceral transplant recipients and to provide additional information on the risk of infection and development of CMV disease. METHODS: We studied 10 bowel/multivisceral transplant recipients to investigate the kinetics of CMV infection using real-time polymerase chain reaction (on blood and biopsy tissue samples) and CMV-specific T-cell reconstitution by Enzyme-linked ImmunoSPOT Assay (ELISPOT) that enumerates Interferon-gamma-secreting CMV-specific T cells upon in vitro stimulation with viral antigens (pp65 and IE-1). RESULTS: All patients were seropositive for CMV. According to the pattern of T-cell reconstitution occurring either within the first month after transplantation or later, patients were classified as early (n = 7) or late responders (n = 3). Clinically, early responder patients (3/7; 43%) experienced asymptomatic or mild CMV infections, whereas all late responders (3/3; 100%) developed moderate or severe CMV disease. A reduction in mean and peak CMV viral load was observed in early responders, whereas the onset time of infection did not differ significantly between early and late CMV responders. CONCLUSIONS: A good and early reconstitution of CMV-specific T-cell immune responses after transplantation is a critical determinant in controlling CMV infections. Simultaneous monitoring of CMV infection and CMV-specific T-cell immunity predicts T-cell-mediated control of CMV infection.

Early and late virological monitoring of cytomegalovirus, Epstein-Barr virus, and human herpes virus 6 infections in small bowel/multivisceral transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) are the major causes of graft failure and posttransplantation mortality among small bowel and multivisceral transplantations (SB/MVT). Little is known about human herpes virus 6 (HHV-6) infections in transplant recipients. STUDY PURPOSE: The purposes of this study were to analyze the clinical relevance of CMV, EBV, and HHV-6 infections after small bowel transplantation and to establish whether routine monitoring for HHV-6 infection should be recommended for the prevention of severe complications in this population. METHODS: Ten adult patients were monitored based on CMV, EBV, and HHV6 DNA quantifications in blood and biopsy tissue samples. Three patients were monitored for at least 5 months (early period) and 7 patients were monitored for 1 to 5 years after transplantation (late period). RESULTS: In the early period, despite prophylaxis all 3 patients developed symptomatic CMV infections: 1 fever/diarrhea, 1 enteritis and rejection, as well as 1 fever and pneumonia. Only 1 patient developed EBV and HHV-6 infections. The average time of onset of CMV infection was 3 months after transplantation and only 24 days for HHV6 infection. In the late period, of the 7 SB/MVT recipients only 1 developed an EBV infection at 2 years after transplantation. No CMV or HHV-6 infections were identified in any patient. CONCLUSIONS: CMV infection is a major cause of organ disease and rejection in the early period after transplantation. EBV infection in adult recipients must be considered also in the late period, particularly in association with severe immunosuppression. Because HHV-6 infection occurs earlier than CMV/EBV, it may serve as an indicator for more intense virological surveillance.

Flow injection analysis with on-line nylon powder extraction for room-temperature phosphorescence determination of thiabendazole.

A fast and very selective flow-through phosphorescence optosensor was designed and characterized for the determination of the fungicide thiabendazole in water samples. For the first time, thiabendazole was determined using a flow-through optosensor based on the phosphorescence signals obtained when it is retained in a solid support. While thiabendazole does not phosphoresce in packing materials commonly used to fill the flow-cell, significant emission signals are observed when it is retained on nylon powder in the presence of iodide and sulfite. The experimental set-up was based on a flow-injection manifold coupled to an on-line phosphorescence detector containing nylon powder packed in a conventional flow-cell. Potassium iodide and sodium sulfite were added to sample aliquots to improve the thiabendazole phosphorescence and injected in the flow manifold using water as carrier. After the phosphorescence emission was registered, the analyte was eluted from the packed nylon with a 65% (v/v) methanol-water mixture. Optimal instrumentation, experimental and flow conditions were evaluated. Using a sample volume of 2000 microL, the analytical signal showed a very good linearity in the range 12.9-110 ng mL(-1), with a detection limit of 4.5 ng mL(-1), and a sample throughput of about 14 samples per hour. The effects of the presence of concomitant species in the thiabendazole phosphorescence signal were studied, and a comparison with the fluorescence nylon-powder optosensor was carried out and discussed. Finally, the applicability of the proposed optosensor was tested in water samples, and satisfactory recoveries ranging between 97% and 105% were obtained.

A novel flow-through fluorescence optosensor for the determination of thiabendazole.

This paper presents the development of a new flow-injection system combined with solid-surface fluorescence detection for the determination of the widely used fungicide thiabendazole. Nylon powder was probed as a novel solid support for building the optosensor. The method is based on the on-line immobilization of thiabendazole onto nylon in a continuous flow system, followed by the measurement of its native fluorescence. Aqueous samples are directly injected in a water carrier, resulting in a very simple and economical method. The analytical figures of merit obtained using 1500 microL of sample and 75% methanol (v/v) as eluting solution were: linear calibration range from 8 to 120 ng mL(-1) (the lowest value corresponds to the quantitation limit), relative standard deviation, 0.9% (n=5) at a level of 64 ng mL(-1), limit of detection calculated according to 1995 IUPAC recommendations is to 2.8 ng mL(-1), and sampling rate of 14 samples h(-1). The potential interference from other agrochemicals, metal ions and common anions, and the viability of determining thiabendazole in real water samples were also evaluated.